Antitrust Reform and Big Tech Firms

August 13, 2021 – November 21, 2023 R46875

Antitrust Reform and Big Tech Firms
September 13, 2023
Antitrust has become a hot topic. After decades as a mostly technocratic discipline, competition
policy now commands the attention of lawmakers, academics, and the general public.
Jay B. Sykes
Legislative Attorney
One of the driving forces behind this trend has been the rise of a handful of large technology

firms: Facebook (now Meta Platforms), Google, Amazon, and Apple. While these “Big Tech”
companies have affected the daily lives of billions, they are also accused of obtaining and
For a copy of the full report,
solidifying dominant positions through anticompetitive conduct.
please call 7-5700 or visit
www.crs.gov.
Meta is currently defending a Federal Trade Commission (FTC) lawsuit that seeks to unwind its
acquisitions of the photo-sharing service Instagram and the messaging app WhatsApp.
Google is embroiled in litigation with the Department of Justice (DOJ), state attorneys general, and private plaintiffs over
alleged exclusionary conduct related to its search engine, app distribution on Android mobile devices, and its
digital-advertising businesses.
The FTC and a putative class of private plaintiffs have accused Amazon of stifling competition among online marketplaces.
The lawsuits allege that Amazon has excluded rivals by implementing policies that punish sellers for discounting their
products on other websites. The FTC’s complaint also claims that Amazon has tied its Prime subscription program to the use
of its fulfillment services, hindering the development of independent fulfillment providers that could make selling on other
marketplaces more attractive.
Several of Apple’s practices have attracted scrutiny, including the firm’s restrictions on the distribution of iOS apps, its use
of competitively sensitive information derived from third-party app developers, and its treatment of its proprietary apps.
Some lawmakers have also expressed concern about the large number of acquisitions that the Big Tech firms have
undertaken over the past decade. In particular, they have worried about the possibility that some of these transactions
eliminated sources of potential or nascent competition.
Many of these concerns have prompted calls for legal reform. Some commentators have argued that ex post adjudication is
ill-equipped to grapple with competition issues in platform markets that have tipped in favor of a single dominant firm. Other
critiques of the existing framework focus on specific doctrinal rules or the alleged shortcomings of the consumer-welfare
standard—a general normative benchmark that has heavily influenced current law.
For their part, defenders of existing law have emphasized the differences between the Big Tech firms. This heterogeneity,
they contend, counsels in favor of the fact-specific approach employed by current doctrine and against categorical regulatory
treatment. Supporters of the consumer-welfare standard argue that it provides a principled and coherent decision-making
framework, in contrast to alternative regimes that would embrace more amorphous goals.
While some reform proposals would adopt special competition regulations for large tech platforms, others would work within
existing antitrust law by adjusting burdens of proof and changing certain doctrinal requirements.
The regulatory route raises questions of how to scope the relevant regulations and select an appropriate regulator to
administer them. On the issue of scope, two general models have emerged. One would allow a regulator to designate covered
platforms that offer specified services and meet certain quantitative and qualitative criteria. Designated firms would then be
subject to the same set of special competition regulations. The other approach is more targeted and would apply special
regulations to individual markets.
As a substantive matter, proposals to reform the competition laws governing Big Tech firms fall into five categories:
(1) ex ante conduct rules, (2) structural separation and line-of-business restrictions, (3) special merger rules,
(4) interoperability and data-portability mandates, and (5) changes to general antitrust doctrine.
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Contacts
Author Information ........................................................................................................................ 77

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n 2012, a prominent scholar lamented the diminished significance of antitrust in the United
States.1 Although there was once a flourishing antitrust movement, he argued, the subject
appeared to attract little interest from lawmakers, academics, and the public.2 Political
I candidates rarely mentioned competition issues, opinion polls reflected indifference toward
economic concentration, and the enforcement agencies seemed to operate with a narrow
view of antitrust’s goals.3
Things have changed. In the past several years, antitrust has resurfaced as a topic of both popular
and political concern.4 The White House has issued an executive order outlining a
“whole-of-government” approach to competition policy;5 advocates of reform have been
appointed to lead the Federal Trade Commission (FTC) and the Department of Justice’s (DOJ’s)
Antitrust Division;6 and Congress has considered a suite of proposals to overhaul various aspects
of antitrust doctrine.7
In the words of one commentator, antitrust now “stands at its most fluid and negotiable moment
in a generation.”8 The subject has not had such political salience, another contends, since 1912.9
Interest in reform has been wide-ranging: “[e]verything is up for grabs, and nothing is free of
scrutiny.”10
One of the driving forces behind this trend has been the rise of a handful of large technology
firms: Facebook (now Meta Platforms), Google, Amazon, and Apple. In 2020, a House
subcommittee released a detailed report (the HJC Report) concluding that the four companies had
obtained and solidified dominant positions through anticompetitive conduct.11 These “Big Tech”
firms have also faced antitrust lawsuits from regulators and private plaintiffs, both in the United
States and abroad.12
This report provides an overview of antitrust issues involving the four Big Tech firms and related
proposals for legislative reform. It is divided into four parts. First, the report provides an
introduction to basic antitrust principles. Second, it reviews selected antitrust allegations against
the Big Tech companies. Third, it discusses conceptual issues with proposals to reform the

1 Maurice E. Stucke, Reconsidering Antitrust’s Goals, 53 B.C. L. REV. 551, 553 (2012).
2 Id. at 553-56.
3 Id.
4 Daniel A. Crane, Antitrust’s Unconventional Politics, 104 VA. L. REV. ONLINE 118, 118-21 (2018).
5 Exec. Order No. 14,036, Promoting Competition in the American Economy, 86 Fed. Reg. 36,987, 36,989 (July 14,
2021).
6 Brent Kendall, Senate Confirms Jonathan Kanter as Justice Department Antitrust Chief, WALL ST. J. (Nov. 16, 2021),
https://www.wsj.com/articles/senate-confirms-jonathan-kanter-as-justice-department-antitrust-chief-11637104400;
David McCabe & Cecilia Kang, Biden Names Lina Khan, a Big-Tech Critic, as F.T.C. Chair, N.Y. TIMES (June 15,
2021), https://www.nytimes.com/2021/06/15/technology/lina-khan-ftc.html.
7 See, e.g., American Innovation and Choice Online Act, S. 2033, 118th Cong. (2023); Prohibiting Anticompetitive
Mergers Act of 2022, S. 3847, 117th Cong. (2022); Platform Competition and Opportunity Act, S. 3197, 117th Cong.
(2021); Trust-Busting for the Twenty-First Century Act, S. 1074, 117th Cong. (2021); Competition and Antitrust Law
Enforcement Reform Act of 2021, S. 225, 117th Cong. (2021); Ending Platform Monopolies Act, H.R. 3825, 117th
Cong. (2021).
8 Crane, supra note 4, at 118.
9 Carl Shapiro, Antitrust in a Time of Populism, 61 INT’L J. INDUS. ORG. 714, 715 (2018).
10 ALAN J. DEVLIN, REFORMING ANTITRUST 265 (2021).
11 INVESTIGATION OF COMPETITION IN DIGITAL MARKETS, MAJORITY STAFF REPORT AND RECOMMENDATIONS, SUBCOMM.
ON ANTITRUST, COMMERCIAL AND ADMIN. L. OF THE H. COMM. ON THE JUDICIARY 12-17 (2020) [hereinafter “HJC
REPORT”]. This report lists the Big Tech firms in the same order as the subcommittee’s report.
12 See infra “The Big Tech Firms: A Summary of Selected Antitrust Allegations.”
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competition laws governing Big Tech. Fourth, the report analyzes the substance of specific
categories of reform proposals.
Antitrust Law: The Basics
The antitrust laws aim to protect economic competition by prohibiting unreasonable restraints of
trade,13 exclusionary conduct by dominant firms,14 and mergers and acquisitions that may
“substantially” lessen competition or “tend to create a monopoly.”15
The following subsections provide a high-level overview of antitrust doctrine to lay the
groundwork for later discussions of competition issues in tech markets and proposals for legal
reform.
Restraints of Trade
Section 1 of the Sherman Act prohibits “every” contract or conspiracy “in restraint of trade.”16
Despite this categorical language, the Supreme Court has interpreted Section 1 to bar only
unreasonable restraints of trade that harm competition.17
Applying this general standard, the Court has identified some types of agreements that are so
likely to be anticompetitive that they are deemed per se illegal, meaning courts need not inquire
into their effects in individual cases.18 Restraints in this category include agreements among
competitors (“horizontal” agreements) to fix prices,19 divide markets,20 and restrain output.21
While some types of agreements are per se illegal under Section 1, most restraints are evaluated
using a standard called the “rule of reason.”22 Under the rule of reason, courts conduct
fact-specific assessments of a defendant’s market power and the details of a challenged agreement
to determine a restraint’s competitive effects.23
This inquiry typically proceeds via a three-step burden-shifting framework. In that framework,
the plaintiff has the initial burden to prove that the challenged restraint has a substantial
anticompetitive effect.24 Plaintiffs can make this showing directly or indirectly. Direct evidence of
anticompetitive harm involves “proof of actual detrimental effects on competition,” such as
reduced output, increased prices, or decreased quality.25 The indirect route involves proof of
market power,26 plus “some evidence that the challenged restraint harms competition”—for

13 15 U.S.C. § 1.
14 Id. § 2.
15 Id. § 18.
16 Id. § 1.
17 Texaco Inc. v. Dagher, 547 U.S. 1, 5 (2006).
18 Id.
19 United States v. Socony-Vacuum Oil Co., 310 U.S. 150, 218 (1940).
20 N. Pac. R.R. Co. v. United States, 356 U.S. 1, 5 (1958).
21 NCAA v. Bd. of Regents of Univ. of Okla., 468 U.S. 85, 100 (1984).
22 Ohio v. Am. Express Co. (Amex), 138 S. Ct. 2274, 2283-84 (2018).
23 Id. at 2284.
24 Id.
25 Id. (cleaned up).
26 The Supreme Court has offered various definitions of “market power,” many of which are related to a firm’s ability
(continued...)
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example, evidence that the restraint is the type of restriction that tends to produce anticompetitive
outcomes.27
If the plaintiff makes a prima facie case of anticompetitive harm, the burden shifts to the
defendant to show a procompetitive justification for the challenged restraint.28 For example, a
defendant might argue that the restraint increases output, creates operational efficiencies, makes a
new product available, enhances product quality, or broadens consumer choice.29
If the defendant makes this showing, the burden shifts back to the plaintiff to demonstrate that the
relevant procompetitive benefits could be reasonably achieved through less anticompetitive
means.30 Some courts have also added a fourth step in which they balance a restraint’s
anticompetitive and procompetitive effects.31
Although most agreements are evaluated under this framework, courts have also recognized a
third standard that lies between the full rule of reason and per se illegality. This intermediate
approach—often called “quick look” review—has been applied to agreements that are not per se
unlawful but nevertheless exhibit characteristics that make their likely anticompetitive effects
clear.32 Different courts have described quick-look analysis in different ways.33 The basic idea,
however, is that the plaintiff in a quick-look case can discharge its initial burden without the type
of detailed evidence of competitive harm required under the full rule of reason.34 Defendants in
quick-look cases, meanwhile, have the opportunity to offer procompetitive justifications for their
conduct, distinguishing quick-look review from per se analysis.35

to profitably charge prices higher than those that would exist in a competitive market—that is, a market with many
buyers and sellers, homogeneous products, perfect information, no barriers to entry or exit, and no transaction costs.
LAWRENCE A. SULLIVAN, ET AL., THE LAW OF ANTITRUST: AN INTEGRATED HANDBOOK 47-48 (4th ed. 2023). Those
definitions sweep quite broadly, however, because virtually every firm selling a differentiated product has some market
power in this sense; perfect competition is a theoretical abstraction that seldom—if ever—exists in the real world. Id. at
47. Commentators have thus observed that, in practice, the legal concept of market power appears to demand a
substantial degree of pricing power. DANIEL FRANCIS & CHRISTOPHER JON SPRIGMAN, ANTITRUST: PRINCIPLES, CASES,
AND MATERIALS 73 (2023). As discussed below, courts typically assess allegations of market power by evaluating
structural factors like a firm’s market share and any entry barriers in the relevant market. Id. at 116. A market share of
less than 30% is typically insufficient for market power. Id. In contrast, a share of 44% has been deemed sufficient
when accompanied by evidence that entry barriers are high and that competitors cannot readily expand their output. Id.
Higher shares have also supported an inference of market power when paired with evidence of entry barriers. Id.
(collecting cases). The process for defining antitrust markets is discussed below.
27 Amex, 138 S. Ct. at 2284.
28 Id.
29 Law v. NCAA, 134 F.3d 1010, 1023 (10th Cir. 1998).
30 Amex, 138 S. Ct. at 2284.
31 See, e.g., Epic Games, Inc. v. Apple, Inc., 67 F.4th 946, 993-94 (9th Cir. 2023) (recognizing that Supreme Court
precedent “neither requires nor disavows” a fourth step, while interpreting Ninth Circuit precedent to require a fourth
balancing step); see also Michael A. Carrier, The Rule of Reason: An Empirical Update for the 21st Century, 16 GEO.
MASON L. REV. 827, 827 (2009) (concluding that courts reached a fourth “balancing” step in 4% of rule-of-reason cases
decided between 1977 and 1999).
32 Herbert Hovenkamp, The Rule of Reason, 70 FLA. L. REV. 81, 122-31 (2018) [hereinafter “Hovenkamp, The Rule of
Reason”]. Often, “quick look” analysis is described as a type of rule-of-reason analysis, rather than a third standard of
review, on the theory that the rule of reason represents a sliding scale that imposes different requirements based on the
context. See id. at 123-24 (rejecting the idea that quick-look review represents a third “silo” of antitrust analysis that is
distinct from the rule of reason).
33 Id. at 122.
34 FRANCIS & SPRIGMAN, supra note 26, at 191.
35 Id.
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Monopolization
While Section 1 of the Sherman Act governs agreements between firms, Section 2 prohibits
dominant companies from engaging in concerted or unilateral exclusionary conduct by making it
unlawful to monopolize, attempt to monopolize, or conspire to monopolize.36
The monopolization offense has two elements:
1. the possession of monopoly power; and
2. “the willful acquisition or maintenance of that power as distinguished from
growth or development as a consequence of a superior product, business acumen,
or historical accident.”37
The second element is often referred to as “exclusionary” or “anticompetitive” conduct.38
Monopoly Power
The Supreme Court has explained that a firm possesses monopoly power if it has the ability to
“control prices or exclude competition.”39 Although that standard is similar to many descriptions
of market power,40 the Court has clarified that monopoly power under Section 2 of the Sherman
Act requires “something greater” than market power under Section 1.41 Courts have thus
concluded that monopoly power entails a large degree of market power.42
Some courts have held that monopoly power can be established through direct evidence of
supra-competitive prices and restricted output.43 However, this type of direct proof is rarely
available.44 As a result, courts typically evaluate allegations of monopoly power by examining
structural factors like a defendant’s market share and any entry barriers in the relevant market.45
These inquiries require a plaintiff to define the scope of the relevant market—an exercise that
turns on the range of items that are reasonable substitutes for one another.46
There are two general approaches to market definition. One approach—the hypothetical
monopolist test (HMT)—attempts to identify the smallest grouping of products over which a

36 15 U.S.C. § 2.
37 United States v. Grinnell Corp., 384 U.S. 563, 570-71 (1966).
38 See, e.g., EINER ELHAUGE, UNITED STATES ANTITRUST LAW AND ECONOMICS 211 (3d ed. 2018).
39 United States v. E.I. du Pont de Nemours & Co., 351 U.S. 377, 391 (1956).
40 See, e.g., Fortner Enters. v. U.S. Steel Corp., 394 U.S. 495, 503 (1969) (defining market power as “the ability of a
single seller to raise price and restrict output”).
41 Eastman Kodak Co. v. Image Tech. Servs., Inc., 504 U.S. 451, 481 (1992).
42 See, e.g., Bacchus Indus., Inc. v. Arvin Indus., Inc., 939 F.2d 887, 894 (10th Cir. 1991); Deauville Corp. v. Federated
Dep’t Stores, Inc., 756 F.2d 1183, 1192 n.6 (5th Cir. 1985). As noted, the legal concept of “market power” in practice
appears to involve a substantial degree of “market power” as that concept is used in economic theory. See supra
note 26. One commentator has thus observed that monopoly power requires “a substantial degree of a sort of power that
is itself defined to exist only when substantial.” Einer Elhauge, Defining Better Monopolization Standards, 56 STAN. L.
REV. 253, 259 (2003).
43 Broadcom Corp. v. Qualcomm Inc., 501 F.3d 297, 307 (3d Cir. 2007); PepsiCo, Inc. v. Coca-Cola Co., 315 F.3d 101,
107 (2d Cir. 2002) (per curiam); Conwood Co. v. U.S. Tobacco Co., 290 F.3d 768, 783 n.2 (6th Cir. 2002).
44 United States v. Microsoft Corp., 253 F.3d 34, 51 (D.C. Cir. 2001) (per curiam). Direct proof of market power is
rarely available for a variety of reasons. Perhaps most significantly, it can be difficult to identify and measure a firm’s
marginal costs. PHILLIP AREEDA, ET AL., ANTITRUST ANALYSIS: PROBLEMS, TEXT, AND CASES 529 (7th ed. 2013).
45 Microsoft, 253 F.3d at 51.
46 United States v. E.I. du Pont de Nemours & Co., 351 U.S. 377, 395 (1956).
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single seller could exercise significant market power.47 Under a version of the HMT known as the
SSNIP test, this inquiry starts with the product at issue in a given case and asks whether a
hypothetical monopolist selling that product could profitably increase its price by a significant
amount (typically 5%-10%) for a non-transitory period of time (typically one year or more).48 If
the answer is yes, then the product represents a relevant antitrust market. However, if consumer
substitution would render such a price increase unprofitable, the SSNIP test prescribes that the
market must be expanded to include substitute products. This process continues until the point at
which a “small but significant non-transitory increase in price” for one of the products would be
profitable.49
A second approach to market definition involves an evaluation of qualitative similarities and
differences between products and services. This methodology is derived from the Supreme
Court’s 1962 decision in Brown Shoe Co. v. United States, which identified a series of “practical
indicia” that may be relevant to an evaluation of a market’s boundaries.50 These qualitative factors
include industry or public recognition of separate markets, a product’s peculiar characteristics and
uses, unique production facilities, distinct customers, distinct prices, sensitivity to price changes,
and specialized vendors.51
The HMT and Brown Shoe’s qualitative inquiry both attempt to determine the range of substitutes
that constrain a firm’s exercise of market power,52 and judicial decisions often employ both
approaches in defining markets.53
As mentioned, once a market has been defined, courts typically assess claims of monopoly power
by evaluating a defendant’s market share and other structural factors like entry barriers.54 When
entry barriers are present, a market share in excess of 70% can establish a prima facie case of

47 Gregory J. Werden, The 1982 Merger Guidelines and the Ascent of the Hypothetical Monopolist Paradigm, 71
ANTITRUST L.J. 253, 253-54 (2003).
48 FRANCIS & SPRIGMAN, supra note 26, at 68.
49 Id. The SSNIP test runs into a well-recognized baseline problem in cases where a firm is alleged to be charging
monopoly prices. In those cases, a SSNIP above prevailing prices may prove unprofitable not because a candidate
market is too small to confer significant pricing power on a hypothetical monopolist, but because the defendant is
already fully exploiting its monopoly power. The use of prevailing prices to define markets in such circumstances is
often called the “Cellophane fallacy,” because the Supreme Court committed this alleged error in a 1956
monopolization case involving cellophane and other packaging materials. E.I. du Pont de Nemours & Co., 351 U.S. at
400-01. Regulators and courts can avoid this problem by using competitive prices rather than prevailing prices as the
baseline for evaluating whether a SSNIP would be profitable. AREEDA, ET AL., supra note 44, at 552; see also DEP’T OF
JUST. & FED. TRADE COMM’N, HORIZONTAL MERGER GUIDELINES § 4.1.2 (2010) [hereinafter “HORIZONTAL MERGER
GUIDELINES”] (acknowledging that use of the SSNIP test may require this modification in certain cases). That
approach, however, raises the same difficulties with determining competitive prices that often bedevil attempts to
establish market power with direct evidence. AREEDA, ET AL., supra note 44, at 552. A widely referenced textbook
notes that the courts “have avoided tackling this issue and mostly act as if raising price above competitive levels were a
self-evidently meaningful and applicable standard.” Id.
50 370 U.S. 294, 325 (1962).
51 Id.
52 FRANCIS & SPRIGMAN, supra note 26, at 74. The above discussion focuses on one component of market definition:
the relevant product market. In certain cases—for example, where transportation costs are high or consumers prefer a
local provider—geography may also represent an important aspect of market definition. Id. at 111.
53 E.g., United States v. Bertelsmann SE & Co., 2022 WL 16949715 at *12-13, 19-20 (D.D.C. 2022); United States v.
H&R Block, Inc., 833 F. Supp. 2d 36, 50-60 (D.D.C. 2011); Olin Corp. v. FTC, 986 F.2d 1295, 1298-99 (9th Cir.
1993).
54 See, e.g., U.S. Anchor Mfg., Inc. v. Rule Indus., Inc., 7 F.3d 986, 999 (11th Cir. 1993).
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monopoly power.55 Courts rarely find monopoly power, by contrast, when a firm’s market share is
less than 50%.56 Shares between 50% and 70% present “the greatest uncertainty,”57 with some
courts deeming shares in that range to be insufficient absent additional evidence.58
To establish monopoly power, plaintiffs also typically must show that a defendant’s dominant
position is likely to be durable—for example, with evidence of significant barriers to entry.59
Entry barriers may include legal and regulatory requirements, control of an essential resource,
entrenched buyer preferences, and economies of scale.60 In some digital markets, entry barriers
may also emerge from network effects (which cause a product’s utility to increase as it gains
more users) and significant switching costs (high costs that users of a product would face in
switching to a substitute).61
Exclusionary Conduct
As noted, the second element of a monopolization claim is exclusionary conduct. The Supreme
Court has described this element as involving “the willful acquisition or maintenance of
[monopoly] power as distinguished from growth or development as a consequence of a superior
product, business acumen, or historical accident.”62
As a general standard, many have found that description unhelpful. Firms often “willfully” try to
obtain monopoly status by developing superior products and by deploying business acumen.63
Moreover, in offering the above formulation, the Supreme Court did not define “business
acumen,” leaving little guidance as to when practices like aggressive price cutting, bundling
separate products, or refusing to share property with rivals represent savvy strategy as opposed to
unlawful exclusion.64
While academics have made several attempts to develop an alternative general standard, courts
have not decisively embraced any of them.65 Instead, the doctrine contains a variety of tests that

55 1 ABA SECTION OF ANTITRUST LAW, ANTITRUST DEVELOPMENTS 230 (9th ed. 2022) [hereinafter “ANTITRUST
DEVELOPMENTS”] (collecting cases).
56 Id. at 231.
57 Id. at 231-32.
58 United States v. Dentsply Int’l, Inc., 399 F.3d 181, 187 (3d Cir. 2005) (“Absent other pertinent factors, a share
significantly larger than 55% has been required to establish prima facie [monopoly] power.”); PepsiCo, Inc. v.
Coca-Cola Co., 315 F.3d 101, 109 (2d Cir. 2002) (“Absent additional evidence, such as an ability to control prices or
exclude competition, a 64 percent market share is insufficient to infer monopoly power.”); Colo. Interstate Gas Co. v.
Natural Gas Pipeline Co. of Am., 885 F.2d 683, 694 n.18 (10th Cir. 1989) (noting that “lower courts generally require a
minimum market share of between 70% and 80%” to support a finding of monopoly power); Exxon Corp. v. Berwick
Bay Real Estate Partners, 748 F.2d 937, 940 (5th Cir. 1984) (per curiam) (noting that “monopolization is rarely found
when the defendant’s share of the relevant market is below 70%”); United States v. Aluminum Co. of Am., 148 F.2d
416, 424 (2d Cir. 1945) (Hand, J.) (indicating that it is “doubtful” that a share of 64% is sufficient for monopoly
power); but see Tops Mkts., Inc. v. Quality Mkts, Inc., 142 F.3d 90, 99 (2d Cir. 1998) (indicating that a share between
50% and 70% can “occasionally” show monopoly power if other factors support the inference).
59 See, e.g., Lenox MacLaren Surgical Corp. v. Medtronic, Inc., 762 F.3d 1114, 1123-25 (10th Cir. 2014); W. Parcel
Express v. United Parcel Serv. of Am., Inc., 190 F.3d 974, 975 (9th Cir. 1999).
60 Rebel Oil Co., Inc. v. Atlantic Richfield Co., 51 F.3d 1421, 1439 (9th Cir. 1995).
61 FTC v. Facebook, Inc., 581 F. Supp. 3d 34, 51 (D.D.C. 2022).
62 United States v. Grinnell Corp., 384 U.S. 563, 570-71 (1966).
63 See, e.g., Daniel Francis, Making Sense of Monopolization, 84 ANTITRUST L.J. 779, 779-80 (2022).
64 Elhauge, supra note 42, at 263.
65 DEP’T OF JUST., COMPETITION AND MONOPOLY: SINGLE-FIRM CONDUCT UNDER SECTION 2 OF THE SHERMAN ACT 33
(2008) (withdrawn in 2009) [hereinafter “DOJ MONOPOLIZATION REPORT”].
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govern specific categories of conduct, along with a burden-shifting framework that is similar to
the usual rule-of-reason inquiry in Section 1 cases.
The following sections review efforts to develop a unified theory of monopolization and several
of the conduct-specific tests that courts have adopted in place of such a theory.
The Debate over a General Monopolization Standard
Courts have held that a wide range of behavior can violate Section 2 of the Sherman Act. As discussed below, a
monopolist can—depending on the circumstances—violate Section 2 by entering into exclusive contracts with
customers or suppliers, tying or bundling separate products, aggressively cutting prices to deter entry, or refusing
to deal with competitors. Other conduct can also constitute monopolization even if it does not fall neatly into any
particular doctrinal category. See LePage’s, Inc. v. 3M, 324 F.3d 141, 152 (3d Cir. 2003). This diversity has raised a
question: is there a unifying principle that explains when conduct wil qualify as “exclusionary,” as opposed to
representing legitimate “competition on the merits”?
Commentators have proposed different answers. One option—the “profit sacrifice” or “no economic sense”
test—comes in several varieties. The basic idea, however, is that conduct is “exclusionary” only if it would have no
rational purpose other than to exclude rivals. SULLIVAN, ET AL., supra note 26, at 112.
Under the “profit sacrifice” version of this theory, unilateral conduct would be deemed anticompetitive only if it
entails a sacrifice of short-term profits, which the defendant intends to recoup with monopoly prices after
eliminating its rivals. Id. The “no economic sense” variant is potentially broader. It would condemn conduct that
(1) has a tendency to eliminate competition, and (2) would make no economic sense but for that tendency.
Gregory J. Werden, Identifying Exclusionary Conduct Under Section 2: The “No Economic Sense” Test, 73 ANTITRUST L.J.
413, 418 (2006).
These approaches are motivated by a desire to avoid chil ing procompetitive behavior and may offer greater
certainty than the types of balancing tests employed in some monopolization cases. The “profit sacrifice” test has
been criticized for failing to account for cases of costless or cheap exclusion, where a monopolist can exclude
rivals at little expense. While the “no economic sense” test may avoid this objection, some commentators have
faulted it for failing to capture conduct that causes serious anticompetitive harm while creating minor economic
benefits. SULLIVAN, ET AL., supra note 26, at 115. Neither test has been adopted as a general monopolization
standard, but their influence is particularly clear in the doctrine governing predatory pricing and refusals to deal.
An alternative approach would provide that conduct is “exclusionary” if and only if it is likely to exclude from the
defendant’s market an equally or more efficient competitor. RICHARD A. POSNER, ANTITRUST LAW 194-95 (2d. ed.
2001). Like the “profit sacrifice” and “no economic sense” theories, the “equally efficient competitor” test may
avoid the uncertainties that accompany open-ended balancing tests, while stil protecting a monopolist’s efficient
rivals. The test’s critics have argued that competition from less efficient rivals is often desirable, including in cases
where an upstart firm has not yet acquired the scale or expertise to match the incumbent’s efficiency.
Administering this approach may also prove challenging, especial y in cases that do not involve price predation.
DOJ MONOPOLIZATION REPORT, supra note 65, at 44. While the test is grounded in principles from
predatory-pricing cases, it has not been elevated to the status of a general Section 2 standard.
A third theory involves the type of balancing test alluded to above, which is similar to the usual rule-of-reason
inquiry under Section 1. Under this approach, conduct qualifies as “exclusionary” based on its net effect on
consumer welfare. Steven C. Salop, Exclusionary Conduct, Effect on Consumers, and the Flawed Profit-Sacrifice Standard,
73 ANTITRUST L.J. 311, 330 (2006). Because it entails a totality-of-the-circumstances inquiry into competitive harm,
a balancing test may avoid the allegations of underinclusiveness that have been leveled against alternative
approaches. On the other hand, commentators have criticized open-ended balancing for being administratively
costly and making it difficult for firms to predict whether their behavior is permissible, which may deter
procompetitive conduct. DOJ MONOPOLIZATION REPORT, supra note 65, at 37-38. Many courts have employed an
effects-balancing framework in Section 2 cases, but—like other theories—it has not risen to the level of an
all-purpose test. ANTITRUST DEVELOPMENTS, supra note 55, at 325.
Predatory Pricing
Some monopolization cases involve allegations that a defendant aggressively cut prices in an
attempt to exclude rivals from the market—a practice commonly known as predatory pricing.
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Predation has been described as “a play in two acts.”66 In the first stage of a predation scheme, a
firm charges unsustainably low prices to drive rivals from the market or deter entry.67 In the
second, the firm attempts to recoup the losses incurred in the first stage by raising prices to
monopoly levels.68
Predatory pricing has played a notable role in antitrust history and was a part of the federal
government’s landmark monopolization case against the Standard Oil Company, which was
broken up in 1911.69 The practice was also a common target of antitrust enforcement through the
1960s,70 when some courts evaluated predation claims by focusing on whether the defendant
intended to harm rivals.71
Today, matters are different. Beginning in the 1950s, academics affiliated with what came to be
known as the Chicago School of antitrust analysis mounted a critique of prevailing theories of
predatory pricing.72 They claimed, among other things, that predation is typically an irrational
strategy, because monopoly prices charged during the recoupment period will often invite entry,
which will in turn drive prices down to competitive levels.73 Chicago School scholars also
contended that monopolists will usually suffer greater losses from a price war than their
competitors, because large firms tend to make more sales than smaller ones.74 Other academics
from what is often called the modern Harvard School later offered arguments for a less
interventionist posture that were grounded in institutional concerns about the ability of courts to
distinguish predatory pricing from vigorous price competition.75
These criticisms proved highly influential.76 In the 1970s and 1980s, many lower courts took a
more restrictive approach to predation claims, often requiring plaintiffs to show that the
defendant’s prices fell below its costs rather than inquiring into the defendant’s intent.77 The
Supreme Court ultimately ratified this approach in its 1993 Brooke Group decision, which held
that predation plaintiffs must establish that (1) the defendant charged below-cost prices, and
(2) there is a “dangerous probability” that the defendant will recoup its losses by raising prices
upon the elimination of competitors.78

66 FRANCIS & SPRIGMAN, supra note 26, at 341.
67 Id.
68 Id.
69 Standard Oil Co. v. United States, 221 U.S. 1 (1911).
70 William E. Kovacic, The Intellectual DNA of Modern U.S. Competition Law for Dominant Firms: The
Chicago/Harvard Double Helix, 2007 COLUM. BUS. L. REV. 1, 44 (2007).
71 Elhauge, supra note 42, at 268 & n.47 (collecting cases).
72 See, e.g., ROBERT H. BORK, THE ANTITRUST PARADOX: A POLICY AT WAR WITH ITSELF 149-55 (1978); John S.
McGee, Predatory Price Cutting: The Standard Oil (N.J.) Case, 1 J. L. & ECON. 137 (1958).
73 The Chicago critique is controversial. Economists have identified a variety of circumstances in which predation can,
in theory, be a rational business strategy—for example, where entry entails large fixed costs, a dominant firm develops
a predatory reputation, capital markets are imperfect, or predation can deny rivals minimum efficient scale. CHIARA
FUMAGALLI, ET AL., EXCLUSIONARY PRACTICES: THE ECONOMICS OF MONOPOLISATION AND ABUSE OF DOMINANCE 16-45
(2018).
74 McGee, supra note 72, at 140. Price discrimination can mitigate this effect. For example, a monopolist may be able
to limit its losses from predation by cutting prices only in certain markets. FUMAGALLI, ET AL., supra note 73, at 17.
75 See, e.g., Phillip Areeda & Donald F. Turner, Predatory Pricing and Practices Under Section 2 of the Sherman Act,
88 HARV. L. REV. 697 (1975).
76 One commentator has argued that the Areeda-Turner paper “has a strong claim to be the most influential law review
article ever written on an antitrust topic.” Kovacic, supra note 70, at 45.
77 Id. at 45-50.
78 Brooke Grp. Ltd. v. Brown & Williamson Tobacco Corp., 509 U.S. 209, 222-24 (1993).
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These requirements have proven difficult to satisfy. Since the Brooke Group decision, successful
predatory-pricing claims have been rare.79
Refusals to Deal
Another category of potentially exclusionary conduct involves refusals to deal with rivals. In
general, firms—including monopolists—have the right to choose their business partners.80 In
certain cases, however, courts have held that declining to do business with competitors can harm
competition without justification and thus violate the Sherman Act.
In Aspen Skiing Co. v. Aspen Highlands Skiing Corp., for example, the Supreme Court held that a
monopolist of downhill skiing services in Aspen, Colorado violated Section 2 by terminating an
“all-Aspen” ski ticket that it had offered with the plaintiff.81 The defendant also made it difficult
for the plaintiff to replicate the “all-Aspen” package, refusing to sell the plaintiff lift tickets or
accept bank-guaranteed vouchers included in the plaintiff’s replacement ticket package.82 After
concluding that the defendant had failed to offer a plausible efficiency justification for its
conduct, the Supreme Court affirmed a verdict of Section 2 liability.83
However, the Court later cabined the scope of its decision in Aspen Skiing, explaining that the
case lies “at or near the outer boundary” of monopolization law.84 The Court offered this guidance
in Verizon Communications Inc. v. Trinko, in which it held that Verizon did not violate Section 2
by refusing to provide interconnection services to a rival local telephone service provider.85 The
Court distinguished Aspen Skiing on the ground that the monopolist in the latter decision had
terminated “a voluntary (and thus presumably profitable) course of dealing” with the plaintiff,
which suggested a willingness to sacrifice short-term profits for an anticompetitive end.86 The
Court also emphasized that the monopolist in Aspen Skiing refused to deal with its rival even if
compensated at the prices it charged to other customers, which also revealed an anticompetitive
purpose.87 Because those factors were not present in Trinko, the Court held that Verizon’s conduct
did not fall within Aspen Skiing’s “limited exception” to the principle that firms are free to refuse
to deal with their competitors.88
Based on the Supreme Court’s reasoning in Trinko, some lower courts have concluded that
refusal-to-deal plaintiffs must establish that a defendant’s refusal entailed a sacrifice of short-term

79 SULLIVAN, ET AL., supra note 26, at 121; DEVLIN, supra note 10, at 184; Lina M. Khan, Amazon’s Antitrust Paradox,
126 YALE L.J. 710, 730 & n.107 (2017) [hereinafter “Khan, Amazon’s Antitrust Paradox”].
80 See United States v. Colgate & Co., 250 U.S. 300 (1919).
81 472 U.S. 585, 593-94 (1985).
82 Id.
83 Id. at 608-11.
84 Verizon Commc’ns Inc. v. L. Offs. of Curtis V. Trinko, LLP, 540 U.S. 398, 409 (2004).
85 Id. at 409-16.
86 Id. at 409.
87 Id.
88 Id.
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profits for an exclusionary purpose.89 Some courts have also required plaintiffs to establish this
type of profit sacrifice with proof that the defendant terminated a voluntary course of dealing.90
Many circuit courts have also accepted a specific theory of refusal-to-deal liability called the
“essential facilities” doctrine, which the Supreme Court has declined to either recognize or
repudiate.91 To prevail under the essential-facilities doctrine, plaintiffs must establish
1. the control of an “essential facility” by a monopolist;
2. an inability to “practically or reasonably” duplicate the facility;
3. the denial of the use of the facility to a competitor; and
4. the feasibility of providing access to the facility.92
While that doctrine remains on the books as a formal matter,93 two commentators have described
the Supreme Court’s treatment of it as inflicting “death by dicta.”94 Its viability thus remains
uncertain.
Refusal-to-deal doctrine implicates a well-recognized trade-off. On the one hand, compulsory
dealing will often increase static efficiency. Requiring a vertically integrated monopolist to supply
necessary inputs to downstream rivals, for example, may promote price competition in the
downstream market and thereby eliminate allocative inefficiencies.95 Those benefits, however,
may come at the expense of dynamic competition insofar as they reduce incentives to invest and
innovate.96
As Trinko makes clear, antitrust doctrine currently places greater emphasis on the latter concern.97
The Supreme Court has also expressed skepticism about the institutional competence of courts to
craft appropriate remedies in refusal-to-deal cases. The worry is that compulsory dealing will
often require generalist judges to set prices and other contract terms—tasks that are typically the
province of a sectoral regulator.98

89 E.g., Novell, Inc. v. Microsoft Corp., 731 F.3d 1064, 1075 (10th Cir. 2013) (Gorsuch, J.); Covad Commc’ns Co. v.
Bell Atl. Corp., 398 F.3d 666, 675 (D.C. Cir. 2005); but see Viamedia Inc. v. Comcast Corp., 951 F.3d 429, 462
(7th Cir. 2020) (concluding that profit sacrifice is relevant but not always dispositive for refusal-to-deal liability).
90 E.g., FTC v. Qualcomm, Inc., 969 F.3d 974, 993-94 (9th Cir. 2020); Novell, 731 F.3d at 1075; In re Elevator
Antitrust Litig., 502 F.3d 47, 52 (2d Cir. 2007); Covad Commc’ns Co. v. BellSouth Corp., 374 F.3d 1044, 1049 (11th
Cir. 2004).
91 Trinko, 540 U.S. at 410-11.
92 MCI Commc’ns Corp. v. AT&T Co., 708 F.2d 1081, 1132-33 (7th Cir. 1983).
93 See ELHAUGE, supra note 38, at 353 n.91 (collecting circuit court decisions recognizing the doctrine).
94 Brett Frischmann & Spencer Weber Waller, Revitalizing Essential Facilities, 75 ANTITRUST L.J. 1, 3 (2008); see also
HERBERT HOVENKAMP, FEDERAL ANTITRUST POLICY: THE LAW OF COMPETITION AND ITS PRACTICE 337 (4th ed. 2011)
[hereinafter “HOVENKAMP, FEDERAL ANTITRUST POLICY”] (concluding that “[n]ot many essential facility claims will
survive” post-Trinko); Khan, Amazon’s Antitrust Paradox, supra note 79, at 801 (noting that commentators have
wondered whether the essential-facilities doctrine is now “a dead letter”).
95 Howard A. Shelanski, Unilateral Refusals to Deal in Intellectual and Other Property, 76 ANTITRUST L.J. 369, 371
(2009).
96 Id.
97 Verizon Commc’ns Inc. v. L. Offs. of Curtis V. Trinko, LLP, 540 U.S. 398, 407-08 (2004) (“Firms may acquire
monopoly power by establishing an infrastructure that renders them uniquely suited to serve their customers.
Compelling such firms to share the source of their advantage is in some tension with the underlying purpose of antitrust
law, since it may lessen the incentive for the monopolist, the rival, or both to invest in those economically beneficial
facilities.”).
98 Id. at 408.
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As discussed below, in many cases, permissive refusal-to-deal doctrine has significant
implications for the viability of antitrust action against major tech platforms under existing law.
Tying
Tying arrangements are vertical restraints of trade (i.e., restraints involving individuals or firms in
a customer-supplier relationship) that can be challenged under several provisions of the antitrust
laws, including Sections 1 and 2 of the Sherman Act.99 Tying involves a refusal to sell one
product (the tying product) unless buyers also purchase another product (the tied product) from
the seller.100
The basic concern with tying arrangements is that they may allow a firm with market power for
the tying product to harm competition in and even monopolize the tied product market.101 Tying
may also help a dominant firm preserve a monopoly in the tying market by eliminating potential
rivals that may enter via the tied market.102
However, tying can also produce procompetitive benefits. For example, tying may dissuade
consumers from using an inferior substitute to the tied product with the tying product, mitigating
the risk of reputational damage to a seller’s brand.103 Producing and selling different products
together may also reduce production, marketing, and distribution costs.104
Some ties can also serve as a means of price discrimination—for example, by allowing firms to
discriminate between high-intensity and low-intensity users of a product.105 Commentators have
debated the effects of these “requirements” or “variable proportion” ties, whereby consumers
purchase a durable tying product (e.g., a printer) and amounts of the tied product (e.g., ink) that
vary with their use of the tying product. Firms may employ these types of ties to lower the price
of the tying product and raise the price of the tied product, benefitting low-volume users and
harming high-volume users.106 Some commentators have argued that “requirements ties” typically
increase total and consumer welfare,107 while others have come to the opposite conclusion.108
Like predatory-pricing doctrine, tying law has changed significantly over the course of antitrust
history. Throughout much of the 20th century, courts were highly skeptical of tying arrangements,

99 HOVENKAMP, FEDERAL ANTITRUST POLICY, supra note 94, at 435.
100 Jefferson Parish Hosp. Dist. No. 2 v. Hyde, 466 U.S. 2 (1984).
101 FUMAGALLI, ET AL., supra note 73, at 352.
102 Id. at 386-88.
103 ELHAUGE, supra note 38, at 419.
104 FUMAGALLI, ET AL., supra note 73, at 353.
105 Dennis W. Carlton & Michael Waldman, Tying, in 3 ISSUES IN COMPETITION LAW AND POLICY 1859, 1866 (Wayne
Dale Collins ed., 2008).
106 Erik Hovenkamp & Herbert J. Hovenkamp, Tying Arrangements and Antitrust Harm, 52 ARIZ. L. REV. 925, 951-52
(2010).
107 Id. at 925. One observer has analogized certain conduct in tech markets to requirements ties, arguing that restrictions
on app distribution may allow Apple to cut iPhone prices, meaning high-intensity app users effectively subsidize
low-intensity users. Thomas A. Lambert, Addressing Big Tech’s Market Power: A Comparative Institutional Analysis,
75 SMU L. REV. 73, 104 & n.182 (2022).
108 Einer Elhauge, Rehabilitating Jefferson Parish: Why Ties Without a Substantial Foreclosure Share Should Not Be
Per Se Legal, 80 ANTITRUST L.J. 463, 476-86 (2016).
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which were deemed per se illegal under Section 1 of the Sherman Act.109 During this period of
disapproval, the Supreme Court consistently described tying as inherently anticompetitive.110
As in other areas of antitrust, academic work challenged this attitude. Beginning in the 1950s,
Chicago School scholars criticized the theory that a firm could leverage power in one market to
extract additional profits from another market. They argued that when consumers use
complementary products in fixed proportions—for example, nuts and bolts—a monopolist cannot
extract additional profits by tying one product to the other.111 In such cases, they reasoned, there
is one profit-maximizing price for the product set, meaning a monopolist of nuts could extract
only one monopoly profit from the nut-bolt set. If the market for bolts is competitive, charging a
monopoly price for nuts while tying them to bolts sold at a supra-competitive price would result
in a price for the nut-bolt set that exceeds the profit-maximizing level.112 The Chicago critique of
leverage theory thus contended that, in these circumstances, firms likely employ tying
arrangements because they generate efficiencies.113
The single monopoly profit theory (SMPT) described above applies only under certain restrictive
assumptions.114 In addition to being limited to complementary products used in fixed
proportions,115 the SMPT does not eliminate the possibility that a firm may employ a tying
arrangement to impair the efficiency of rivals in the tied market. If there are necessary scale
economies in the tied market, for example, tying can potentially allow a firm to deny those
economies to rivals and thus decrease the competitiveness of that market.116 The SMPT also does
not preclude the use of a tying arrangement to maintain market power in the tying market (i.e., in
cases where firms may enter the tying market via the tied market).117
Despite these limitations, the Chicago critique of traditional leverage theory—along with the
development of various efficiency-based rationales for tying—ultimately led courts to move away
from the view that ties are almost invariably anticompetitive.118 This change prompted an erosion
of the per se rule. In decisions in the 1970s and 1980s, the Supreme Court retained the label of
per se illegality for tying arrangements, but limited the rule’s application to firms with sufficient
market power in the tying market to force purchases of the tied product.119

109 N. Pac. Ry. Co. v. United States, 356 U.S. 1, 3 (1958).
110 Fortner Enters. v. U.S. Steel Corp., 394 U.S. 495, 503 (1969) (stating that tying arrangements “generally serve no
legitimate business purpose that cannot be achieved in some less restrictive way”); Standard Oil Co. v. United States,
337 U.S. 293, 305-06 (1949) (concluding that tying arrangements “serve hardly any purpose beyond the suppression of
competition”).
111 Ward S. Bowman, Jr., Tying Arrangements and the Leverage Problem, 67 YALE L.J. 19, 23 (1957).
112 Id.
113 Id. at 29.
114 FUMAGALLI, ET AL., supra note 73, at 367-99.
115 As discussed, commentators have taken different views on the welfare effects of ties involving products used in
variable proportions.
116 Einer Elhauge, Tying, Bundling, and the Death of the Single Monopoly Profit Theory, 123 HARV. L. REV. 397, 413
(2009).
117 Id. at 417-19.
118 Ill. Tool Works Inc. v. Independent Ink, Inc., 547 U.S. 28, 35-36 (2006) (noting that “[o]ver the years,” the Court’s
“strong disapproval of tying arrangements has substantially diminished,” and that the case law had rejected the
assumption that tying arrangements usually have no procompetitive purpose).
119 Jefferson Parish Hosp. Dist. No. 2 v. Hyde, 466 U.S. 2, 13-16 (1984); U.S. Steel Corp. v. Fortner Enters., Inc., 429
U.S. 610, 620-22 (1977).
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Lower courts have adopted different formulations of this modified per se rule, but the inquiries
are generally similar.120 One commentator has summarized the doctrine as establishing the
following requirements for a per se tying claim under Section 1:
1. The defendant offered two distinct products;
2. The defendant conditioned the sale of one product (the tying product) on the
purchase of the other product (the tied product);
3. The defendant possessed sufficient economic power in the tying product market
to coerce purchasers into acceptance of the tied product; and
4. The defendant’s conduct affected a “not insubstantial” amount of interstate
commerce in the tied product (an inquiry that focuses on the absolute dollar
amount of affected commerce).121
Some lower courts have also required plaintiffs to demonstrate that a tying arrangement had
anticompetitive effects in the tied product market.122 Others have entertained and accepted
business justifications for challenged ties.123 In practice, then, the modified per se rule against
tying appears to be more similar to the rule of reason than it is to traditional per se rules.124
Courts have also declined to apply the modified per se rule to ties involving platform software
products. In its 2001 decision in United States v. Microsoft, the D.C. Circuit held that a tie
involving Microsoft’s Windows operating system and its Internet Explorer web browser was
governed by the rule of reason, rather than the modified per se rule.125 In rejecting application of
the per se rule, the D.C. Circuit noted that none of the Supreme Court’s tying cases had involved
the physical and technological integration of separate products.126 Condemning such ties without
evaluating their competitive effects, the court reasoned, would create an unacceptable risk of error
and deter innovation.127 In 2023, the Ninth Circuit adopted the D.C. Circuit’s reasoning to
conclude that the rule of reason applied to a tying claim challenging Apple’s requirement that
software developers use Apple’s payment processor for in-app purchases as a condition of
distributing apps through its App Store.128
As mentioned, tying arrangements can be challenged under Sections 1 and 2 of the Sherman Act.
The key differences between the provisions are Section 1’s requirement of an agreement; the
availability of the modified per se rule under Section 1; and Section 2’s requirement that
challenged conduct contribute to the creation or maintenance of monopoly power (or produce a
dangerous probability of those effects).129

120 HOVENKAMP, FEDERAL ANTITRUST POLICY, supra note 94, at 435 (explaining that “[i]n operation the tests are
similar,” but that some courts have combined elements that other courts recognize as separate requirements).
121 Id. The Supreme Court has held that $60,800 in sales was sufficient to meet the “not insubstantial” volume
requirement, while some lower courts have held that considerably lower volumes are sufficient. ANTITRUST
DEVELOPMENTS, supra note 55, at 197 (collecting cases).
122 E.g., Kaufman v. Time Warner, 836 F.3d 137, 141 (2d Cir. 2016); Amey, Inc. v. Gulf Abstract & Title Inc., 758
F.2d 1486, 1503 (11th Cir. 1985); Driskill v. Dallas Cowboys Football Club, Inc., 498 F.2d 321, 323 (5th Cir. 1974).
123 ANTITRUST DEVELOPMENTS, supra note 55, at 200.
124 Viamedia, Inc. v. Comcast Corp., 951 F.3d 429, 468 (7th Cir. 2020) (making this observation).
125 253 F.3d 34, 89-91 (D.C. Cir. 2001) (per curiam).
126 Id.
127 Id.
128 Epic Games, Inc. v. Apple, Inc., 67 F.4th 946, 997 (9th Cir. 2023).
129 FRANCIS & SPRIGMAN, supra note 26, at 382.
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In evaluating product-design or “technological tie” claims under Section 2, some decisions have
held that the integration of separate products is lawful when it improves quality or reduces cost,
even if that conduct forecloses rivals.130 The Microsoft decision, by contrast, employed a
rule-of-reason-like burden-shifting framework to the government’s Section 2 claims in that
case.131 Another appellate decision has affirmed liability for product integration where evidence
of an exclusionary motive cast doubt on the defendant’s argument that the challenged design
represented a genuine improvement.132
Exclusive Dealing
Like tying arrangements, exclusive contracts—in which a firm commits to refrain from dealing
with its counterparty’s rivals—are vertical restraints of trade that can be challenged under
Sections 1 and 2 of the Sherman Act.133
Exclusive contracts can harm competition when a dominant firm uses them to foreclose rivals
from key inputs or distribution channels.134 They can also produce procompetitive benefits. For
example, exclusivity may induce manufacturers to make relationship-specific investments in
dealers by providing sales training, technical support, and other promotional assistance.135 To the
extent that a dealer can use any of this support to promote rival brands, manufacturers may lack
the incentive to provide it. Exclusive dealing can eliminate this free-rider problem and thereby
encourage investment.136 Exclusivity may also mitigate uncertainty about future sales or
purchases137 and encourage more intense competition for distribution, which may result in lower
consumer prices.138
While exclusive dealing has never been deemed per se illegal, its treatment has evolved
considerably. In its 1949 Standard Stations decision, the Supreme Court affirmed a decision
finding that foreclosure of 6.7% of the relevant market was sufficient to render an exclusive
contract illegal.139 In doing so, the Court appeared to approve the lower court’s refusal to engage
in a full rule-of-reason analysis of competitive harm.140 The decision thus stood for what came to
be called the “quantitative substantiality” approach to exclusivity, which focused on the
percentage of the relevant market foreclosed by a challenged agreement.141
The Supreme Court departed from that approach twelve years later in Tampa Electric Co. v.
Nashville Coal Co., where it rejected a challenge to an exclusive contract that foreclosed less than

130 See, e.g., Allied Orthopedic Appliances v. Tyco Health Care Grp., 592 F.3d 991, 1000-02 (9th Cir. 2010); Berkey
Photo, Inc. v. Eastman Kodak Co., 603 F.2d 263, 286-87 (2d Cir. 1979).
131 Microsoft, 253 F.3d at 65-67.
132 C.R. Bard, Inc. v. M3 Systems, 157 F.3d 1340, 1382 (Fed. Cir. 1998).
133 HOVENKAMP, FEDERAL ANTITRUST POLICY, supra note 94, at 478.
134 FUMAGALLI, ET AL., supra note 73, at 239-62.
135 Id. at 273-74.
136 Id.
137 See Standard Oil Co v. United States (Standard Stations), 337 U.S. 293, 306-07 (1949).
138 Benjamin Klein & Kevin M. Murphy, Exclusive Dealing Intensifies Competition for Distribution, 75 ANTITRUST
L.J. 433 (2008). Chicago School academics also questioned why a rational firm would agree to an exclusive contract
that enhanced or preserved the market power of its counterparty. E.g., BORK, supra note 72, at 309. In response,
economists have developed models showing that buyers may face collective action problems when a monopolist uses
exclusive contracts to deny rivals necessary scale economies. FUMAGALLI, ET AL., supra note 73, at 243-54.
139 Standard Stations, 337 U.S. at 308-09.
140 Id.
141 ANTITRUST DEVELOPMENTS, supra note 55, at 209.
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1% of the relevant market.142 In Tampa Electric, the Court did not limit its analysis to the low
foreclosure percentage, explaining that it was necessary to also engage in a qualitative analysis of
the agreement’s competitive effects.143
The quantitative aspect of foreclosure analysis has also become more permissive. In the Court’s
1984 Jefferson Parish decision, the concurring opinion of four Justices concluded, without a
detailed inquiry, that foreclosure of 30% of the market was not sufficient to render an exclusive
contract unlawful.144
Since these decisions, reviewing courts have tended to require foreclosure of at least 40% of the
market before condemning exclusive contracts under Section 1, while also analyzing the duration
of the restrictions, any business justifications, and other factors that may bear on an agreement’s
competitive effects.145
Some courts have indicated that the standards for assessing exclusive dealing are more
plaintiff-friendly under Section 2, and that a monopolist’s use of exclusive contracts may be
illegal even if they foreclose less than the 40% figure that is typically necessary for a Section 1
violation.146
Monopoly Leveraging
A firm’s possession of monopoly power has traditionally given rise to concerns that the firm may use that power
to gain a competitive advantage in another market. For many years, the federal courts split over whether Section 2
precluded this type of “monopoly leveraging” in cases where a defendant utilized its monopoly power to harm
competition in—but not reasonably threaten to monopolize—a second market. Elhauge, supra note 38, at 357-58
nn.97-98 (col ecting cases).
In 2004, the Supreme Court rejected one type of leveraging claim, remarking that the leveraging theory offered in
that case would be valid only if the defendant had a “dangerous probability” of monopolizing a second market—an
element of the attempt-to-monopolize offense. Verizon Commc’ns Inc. v. L. Offs. of Curtis V. Trinko, LLP, 540 U.S. 398,
410 n.4 (2004) (citation omitted). The Court thus rejected the proposition that a defendant could violate
Section 2 merely by gaining an unfair advantage in a second market. As a result, “monopoly leveraging” does not
denote a standalone antitrust offense that is distinct from monopolization or attempted monopolization.
In its 2001 Microsoft decision, however, the D.C. Circuit endorsed what some commentators have called a
“defensive leveraging” theory. See United States v. Microsoft Corp., 253 F.3d 34, 67 (D.C. Cir. 2001) (per curiam);
Robin Cooper Feldman, Defensive Leveraging in Antitrust, 87 GEO. L.J. 2079 (1999). While “offensive leveraging”
involves a defendant’s use of monopoly power in one market to extract additional profits from another market,
“defensive leveraging” involves the use of monopoly power to gain an advantage in another market so as to
prevent erosion of a primary monopoly. See Feldman, Defensive Leveraging, 87 GEO. L.J. at 2080.
In Microsoft, for example, the D.C. Circuit concluded that Microsoft had leveraged its operating-system monopoly
into the market for web browsers so as to protect its operating-system monopoly. Microsoft, 253 F.3d at 64.
Specifically, Microsoft imposed several restrictions related to its Windows operating system that were designed to
reduce the usage of rival web browsers, which threatened to supplant Windows as platforms for software
development. Id. at 60. The D.C. Circuit held that some of this conduct constituted unlawful monopolization. Id. at
64.
Accordingly, under current Section 2 doctrine, an “offensive leveraging” theory requires proof that a defendant’s
conduct raised a “dangerous probability” of monopolizing a second market—a prerequisite for an
attempt-to-monopolize claim. Simply gaining an unfair advantage in another market is not sufficient. Trinko, 540
U.S. at 410 n.4. By contrast, “defensive leveraging”—whereby a monopolist’s leveraging of its monopoly power

142 365 U.S. 320 (1961).
143 Id. at 329.
144 466 U.S. 2, 46 (1984) (O’Connor, J., concurring).
145 HOVENKAMP, FEDERAL ANTITRUST POLICY, supra note 94, at 487.
146 E.g., United States v. Microsoft Corp., 253 F.3d 34, 70 (D.C. Cir. 2001) (per curiam).
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into a second market helps preserve its primary monopoly—is a viable theory of monopoly maintenance, even
without proof that the defendant threatens to monopolize the second market. See Microsoft, 253 F.3d at 64, 80-84.
Mergers & Acquisitions
The antitrust laws also place limitations on mergers and acquisitions.147 Section 7 of the Clayton
Act prohibits a merger if its effect “may be substantially to lessen competition, or to tend to create
a monopoly.”148 Though less common, Section 2 of the Sherman Act has also been used to
challenge mergers that help a firm acquire or maintain monopoly power.149
Analysis of mergers varies based on the relationship between the merging parties—specifically,
based on whether a merger is horizontal, vertical, or conglomerate.
Horizontal mergers (i.e., mergers between competitors) receive the greatest scrutiny and can raise
two primary types of concerns. First, horizontal mergers may allow a firm to unilaterally increase
its prices or decrease the quality of its products by eliminating competition between rivals.150
Second, horizontal mergers may facilitate tacit or express collusion by increasing market
concentration (so-called “coordinated effects”).151
Vertical mergers (i.e., mergers between firms in the same supply chain) receive less exacting
scrutiny than horizontal ones, because they do not eliminate direct competitors and are thought to
often generate efficiencies.152 The main concern with vertical mergers is foreclosure; when a firm
acquires an important source of inputs or a key distribution channel, it may have the ability and
incentive to raise rivals’ costs or refuse to do business with rivals altogether.153 A vertical merger
may also prompt concerns if it gives a firm access to competitively sensitive information about
rivals or facilitates collusion by allowing the merged entity to monitor compliance with tacit
pricing agreements.154
Conglomerate mergers are mergers that are neither horizontal nor vertical.155 Challenges to such
mergers are rare.156 Conglomerate mergers may raise antitrust concerns, however, if they allow a
firm to acquire a potential competitor.157

147 For ease of discussion, this report will refer to both mergers and acquisitions as “mergers.”
148 15 U.S.C. § 18.
149 United States v. Grinnell Corp., 384 U.S. 563, 576 (1966); Fraser v. Major League Soccer, LLC, 284 F.3d 47, 61
(1st Cir. 2002); BRFHH Shreveport, LLC v. Willis Knighton Med. Ctr., 176 F. Supp. 3d 606, 619 (W.D. La. 2016).
150 HORIZONTAL MERGER GUIDELINES, supra note 49, at § 6.
151 Id. § 7.
152 DANIEL A. CRANE, ANTITRUST 164 (2014). By allowing a downstream firm to access inputs at cost instead of paying
a markup, vertical mergers may eliminate the “double marginalization” that occurs when two firms within a supply
chain each mark-up their prices. DEP’T OF JUST. & FED. TRADE COMM’N, VERTICAL MERGER GUIDELINES § 6 (2020)
[hereinafter “VERTICAL MERGER GUIDELINES”] (withdrawn by the FTC in September 2021). The elimination of double
marginalization is a key procompetitive benefit that is often cited in defense of vertical mergers. See id.
153 VERTICAL MERGER GUIDELINES, supra note 152, at § 4.
154 Id. §§ 4-5.
155 ELHAUGE, supra note 38, at 811.
156 Id. at 812.
157 The elimination of potential competition is sometimes described as a horizontal theory of harm, because it involves
the claim that a potential competitor would likely enter the relevant market or that market participants perceive the
potential competitor as being likely to enter their market. CHRISTOPHER L. SAGERS, ANTITRUST 321 n.45 (3d ed. 2021).
As discussed below, however, challenges based on these theories are evaluated under different standards than
challenges to other types of horizontal mergers.
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Merger law has evolved significantly over the last 50 years. During the Warren Court era from the
early 1950s through the 1960s, the Supreme Court heard 12 merger cases, siding with the plaintiff
in each case where it reached the merits.158 Some of the Court’s decisions blocked small mergers
in unconcentrated markets, based in part on a concern about stopping an incipient trend toward
concentration and a desire to effectuate congressional intent to protect small businesses.159
In this period, courts were heavily influenced by an approach to industrial organization often
called the “structure-conduct-performance” (SCP) paradigm, which held that market
concentration tended to produce less competitive markets with higher prices.160 The impact of
these theories was made clear in the Supreme Court’s 1963 decision in United States v.
Philadelphia National Bank, which recognized a presumption of illegality for mergers that would
result in a firm controlling “an undue percentage share of the relevant market” while significantly
increasing market concentration.161
This “structural presumption” remains good law, but subsequent developments have chipped
away at its strength. In its 1974 decision in United States v. General Dynamics Corp., the
Supreme Court held that the defendant coal-mine operator had successfully rebutted the
presumption with evidence that almost all of the acquired firm’s coal reserves were depleted or
committed under long-term contracts.162 Lower court decisions later interpreted General
Dynamics as demanding a more detailed inquiry into a merger’s competitive effects than was
evident in the Warren Court’s merger decisions.163 This shift coincided with a wave of academic
criticism directed at SCP theories. Among other things, SCP’s detractors argued that high levels
of market concentration are often necessary for firms to achieve economies of scale and scope
and that many concentrated markets perform competitively.164
Today, much of the action in merger enforcement takes place in the antitrust agencies rather than
the courts. This is partly the result of Congress’s adoption of the Hart-Scott-Rodino Antitrust
Improvements Act (HSR Act) in 1976, which created a pre-merger notification regime that allows
the DOJ and FTC to review mergers exceeding certain numerical thresholds before they close.165
Since 1968, the agencies have published guidelines outlining their analytical approach to merger
review, including their application of the structural presumption.166 Starting with the 1982
guidelines, the agencies have relied on the Herfindahl-Hirschman Index (HHI) measure of market

158 Eleanor Fox, Antitrust, Mergers, and the Supreme Court: The Politics of Section 7 of the Clayton Act, 26 MERCER L.
REV. 389, 396-97 (1975).
159 E.g., United States v. Von’s Grocery Co., 384 U.S. 270, 278 (1966) (blocking a merger that would have resulted in
the merged firm occupying a 7.5% market share, based on a concern “that a market marked . . . by both a continuous
decline in the number of small businesses and a large number of mergers would slowly but inevitably gravitate from a
market of many small competitors to one dominated by one or a few giants”); Brown Shoe Co. v. United States, 370
U.S. 294, 343-44 (1962) (blocking a merger with both horizontal and vertical elements, based in part on the fact that
the integrated firm would be able to offer lower prices than unintegrated firms); see also FTC v. Procter & Gamble Co.,
386 U.S. 568, 579 (1967) (unwinding a conglomerate transaction involving a large consumer-goods firm and the
leading producer of household liquid bleach, based in part on a concern that economies of scope would disadvantage
smaller rivals).
160 William E. Kovacic & Carl Shapiro, Antitrust Policy: A Century of Economic and Legal Thinking, 14 J. ECON.
PERSP. 43, 52 (2000).
161 374 U.S. 321, 363-64 (1963).
162 415 U.S. 486, 508-11 (1974).
163 SULLIVAN, ET AL., supra note 26, at 464 n.76 (citing examples).
164 HOVENKAMP, FEDERAL ANTITRUST POLICY, supra note 94, at 544.
165 P.L. 94-435, 90 Stat. 1383 (1976).
166 In Philadelphia National Bank, the Supreme Court held that the presumption was triggered by a post-merger market
share of 30%. 370 U.S. at 364. The Court did not address market-concentration thresholds, however.
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concentration in applying the presumption.167 Revisions to the guidelines in 2010 increased the
minimum concentration levels at which the agencies regard horizontal mergers as potentially
problematic.168 While the guidelines are not legally binding, courts often treat them as persuasive
authority and appear to accord some significance to the relevant HHI thresholds.169
As discussed, the structural presumption can be rebutted—for example, with evidence that the
proposed market is poorly defined or that market shares do not reflect a merger’s likely
competitive effects; that the entry of other firms will discipline any pricing power; or that the
merger will produce efficiencies that offset any anticompetitive effects.170 Upon rebuttal of a
prima facie case, the burden of producing further evidence of anticompetitive harm shifts back to
the plaintiff and merges with the burden of persuasion.171
While the case law on vertical mergers is sparse,172 the most recent appellate decision reviewing a
vertical deal employed a burden-shifting approach that is similar to the framework used to
evaluate horizontal mergers.173 However, the court indicated that plaintiffs challenging vertical
mergers cannot rely on the structural presumption to discharge their initial burden.174 Instead, the
court explained that such plaintiffs must make a fact-specific showing that a transaction is likely
to be anticompetitive,175 which will presumably often involve foreclosure concerns.
The current state of merger law is something of an oddity. Although the Supreme Court’s 1960s
merger decisions have not been formally overturned, they do not accurately reflect the “law on
the ground” as applied by the antitrust agencies and the lower courts.176 Since the Warren Court,
for example, merger doctrine has abandoned “non-economic” goals like the protection of small
businesses.177 While structural evidence continues to play a role in merger analysis, its centrality

167 FRANCIS & SPRIGMAN, supra note 26, at 423. The HHI is a measure of market concentration calculated by summing
the squares of each firm’s market share. Thus, a market with four firms that each occupy 25% of the market would
have an HHI of 2,500 (252 + 252 + 252 + 252).
168 Id.
169 SULLIVAN, ET AL., supra note 26, at 500 n.41 (collecting cases).
170 Herbert J. Hovenkamp & Carl Shapiro, Horizontal Mergers, Market Structure, and Burdens of Proof, 127 YALE L.J.
1996, 1997 (2018). The availability of an efficiencies defense in merger cases is not entirely settled. In the 1960s, the
Supreme Court explicitly rejected such a defense and sometimes identified efficiencies as a reason to block mergers.
See FRANCIS & SPRIGMAN, supra note 26, at 494-95. More recently, though, some lower courts have indicated that
evidence of efficiencies can be used to rebut a prima facie showing of competitive harm. Id. at 496 n.688 (collecting
cases). The merger guidelines also provide that certain merger-specific efficiencies may be cognizable. HORIZONTAL
MERGER GUIDELINES, supra note 49, at § 10 (“The Agencies will not challenge a merger if cognizable efficiencies are
of a character and magnitude such that the merger is not likely to be anticompetitive in any relevant market.”). To date,
however, no federal court of appeals has concluded that evidence of efficiencies was sufficient to rebut a prima facie
case of anticompetitive effects. FRANCIS & SPRIGMAN, supra note 26, at 499.
171 Baker Hughes, 908 F.2d at 983.
172 In 2018, the DOJ’s challenge to AT&T’s acquisition of Time Warner became the first vertical transaction litigated
to judgment since the 1970s. Fruehauf Corp. v. FTC, 603 F.3d 345 (2d Cir. 1979).
173 United States v. AT&T, Inc., 916 F.3d 1029, 1032 (D.C. Cir. 2019).
174 Id.
175 Id.
176 SULLIVAN, ET AL., supra note 26, at 466 (noting the “quasi-irrelevance” of the Supreme Court in merger law). The
Supreme Court has not issued a merits opinion in a merger case since 1975. United States v. Citizens & S. Nat’l Bank,
422 U.S. 86 (1975).
177 HERBERT HOVENKAMP, THE ANTITRUST ENTERPRISE: PRINCIPLE AND EXECUTION 208 (2005) [hereinafter
“HOVENKAMP, ANTITRUST ENTERPRISE”] (“While antitrust casebooks continue to print 1960s-vintage merger decisions
that have never been overruled, no one, not even federal judges and certainly not the government enforcement agencies,
pay much attention to them. . . . It is not merely that Supreme Court decisions are not followed on technical grounds—
(continued...)
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has diminished as regulators and courts also consider a broader range of factors that may
illuminate a transaction’s competitive effects.178 That may be changing, however. In 2023, the
DOJ and FTC released draft merger guidelines that appear to place more weight on structural
considerations than previous iterations of the guidelines.179 It remains to be seen whether courts
will follow the agencies in this regard, should the regulators finalize the guidelines in similar
form.
Mergers Involving Potential Competitors
Some mergers involve firms that do not compete at the time of the transaction, but may compete in the future
absent the merger. These mergers between potential competitors can raise two types of concerns. First, if the
perception that a potential competitor may enter a market constrains a firm’s pre-merger pricing behavior, then
allowing the firm to acquire the potential competitor eliminates that constraint. In the doctrine, this concern is
known as the elimination of “perceived potential competition.” Second, if a potential competitor actually would
have entered the relevant market, then a merger would eliminate actual future competition, irrespective of
whether the potential competitor constrained pre-merger behavior. This concern is called the elimination of
“actual potential competition.”
The Supreme Court has held that the elimination of perceived potential competition may render a merger
unlawful, but has not expressly recognized the elimination of actual potential competition as a viable theory of
harm. United States v. Marine Bancorporation, Inc., 418 U.S. 602, 624-25 (1974). The Court has identified several
requirements for a perceived-potential-competition claim. A plaintiff bringing such a claim must show that
•
the relevant market is highly concentrated;
•
the potential competitor has the “characteristics, capabilities, and economic incentive to render it a perceived
potential de novo entrant”; and
•
the potential competitor “in fact tempered oligopolistic behavior” by market participants.
Id. While the Supreme Court has declined to resolve the validity of the actual-potential-competition doctrine, it
has explained that plaintiffs relying on that theory must establish that
•
the relevant market is highly concentrated;
•
the potential competitor has “feasible means” of entry other than through the merger; and
•
the potential competitor’s entry offers a “substantial likelihood” of deconcentrating the market or producing
other significant procompetitive benefits.
Id. at 633. Lower courts have adopted different evidentiary requirements in analyzing whether a firm is likely to
enter the market absent a challenged transaction. The Fourth Circuit demands “clear proof” of entry but for the
merger. FTC v. Atlantic Richfield Co., 549 F.2d 289, 294-95 (4th Cir. 1977). Others have required that the potential
competitor “probably” or “would likely” enter the relevant market. Tenneco, Inc. v. FTC, 689 F.2d 346, 352 (2d Cir.
1982) (“would likely”); Yamaha Motor Co. v. FTC, 657 F.2d 971, 977 (8th Cir. 1981) (“probably”). Another has
demanded a “reasonable probability” of entry, which the court construed to be more demanding than a
“probability” or “more likely than not” test. Mercantile Tex. Corp. v. Bd. of Govs. of the Fed. Res. Sys., 638 F.2d 1255,
1268-69 (5th Cir. 1981).
The impact of potential-competition doctrine has been fairly modest. Three decisions have found a merger
unlawful based on the perceived-potential-competition theory, all of which also relied on the
actual-potential-competition theory. ANTITRUST DEVELOPMENTS, supra note 55, at 398.

the fundamental ideology of mergers has shifted dramatically over the last three decades and now embodies values that
are inconsistent at the most fundamental level with those that the Supreme Court last articulated.”).
178 HOVENKAMP, FEDERAL ANTITRUST POLICY, supra note 94, at 544.
179 U.S. Antitrust Agencies Propose Sweeping Changes to Merger Guidelines—5 Key Things You Need to Know, WHITE
& CASE LLP (July 20, 2023), https://www.whitecase.com/insight-alert/us-antitrust-agencies-propose-sweeping-
changes-merger-guidelines-5-key-things-you. For an overview of the 2023 draft guidelines, see CRS Legal Sidebar
LSB11027, Antitrust Agencies Release Draft Merger Guidelines and Propose HSR Rule Changes, by Peter J. Benson,
Chris D. Linebaugh, and Alexander H. Pepper.
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Theoretical Approaches to Antitrust
As the above discussion makes clear, antitrust doctrine has changed significantly over time, often
in response to shifts in political ideology and economic theory. Congress has played a limited role
in this evolution; the language of the core antitrust statutes has not meaningfully changed since
the Celler-Kefauver Act amended Section 7 of the Clayton Act in 1950.180 Because the flexible
nature of the antitrust laws gives the judiciary broad powers to shape competition policy based on
prevailing economic and political thinking,181 this section provides a brief overview of the leading
theoretical approaches to antitrust and their historical influence.
As discussed, SCP theories exerted a strong influence on antitrust policy in the middle of the 20th
century.182 This approach to industrial organization was developed by scholars working in a
tradition often referred to as the Harvard School, which posited a close causal link between
market concentration, firm conduct, and competitive performance.183 In particular, the SCP
literature held that there was a tight connection between high levels of market concentration and
certain undesirable outcomes, such as high price-cost margins.184
For much of antitrust history—including during the heyday of the SCP paradigm—
“non-economic” goals also played a major role in shaping antitrust doctrine. These goals included
the protection of small businesses, the dispersion of economic power, the preservation of
economic freedom, and the elimination of concentrated political power.185
From the 1940s through the 1960s, structuralist economic theories and the above normative
concerns provided the theoretical architecture for a highly interventionist approach to antitrust,
judged by today’s standards. As discussed, the Warren Court’s merger jurisprudence was quite
restrictive, invalidating small mergers based in part on a desire to “promote competition through
the protection of viable, small, locally owned business,” even if “occasional higher costs and
prices might result from the maintenance of fragmented industries and markets.”186
Conduct cases during this era reflected similar attitudes. In the federal government’s
monopolization case against Alcoa, for example, Judge Learned Hand of the Second Circuit
reasoned that the Sherman Act was motivated in part by a belief that “great industrial
consolidations are inherently undesirable, regardless of their economic results.”187 He thus
construed the statute as an attempt to “put an end to great aggregations of capital because of the
helplessness of the individual before them.”188 Based on these principles, the Second Circuit held

180 Pub. L. No. 81-899, 64 Stat. 1125 (1950).
181 See, e.g., Leegin Creative Leather Prods., Inc. v. PSKS, Inc., 551 U.S. 877, 899 (2007) (“From the beginning the
Court has treated the Sherman Act as a common-law statute. . . . Just as the common law adapts to modern
understanding and greater experience, so too does the Sherman Act’s prohibition on ‘restraint[s] of trade’ evolve to
meet the dynamics of present economic conditions.”) (brackets in original); Nat’l Soc’y of Pro. Eng’rs v. United States,
435 U.S. 679, 688 (1978) (explaining that Congress “expected the courts to give shape to [the Sherman Act’s] broad
mandate by drawing on common-law tradition”).
182 See Kovacic & Shapiro, supra note 160, at 52.
183 ROGER VAN DEN BERGH, COMPARATIVE COMPETITION LAW AND ECONOMICS 33-36 (2017).
184 Id. at 35-36.
185 See, e.g., Stucke, supra note 1, at 560-62; Eleanor M. Fox, Modernization of Antitrust: A New Equilibrium, 66
CORNELL L. REV. 1140, 1182 (1981).
186 Brown Shoe Co. v. United States, 370 U.S. 294, 344 (1962).
187 United States v. Aluminum Co. of Am., 148 F.2d 416, 428 (2d Cir. 1945) (Hand, J.).
188 Id.
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that Alcoa violated Section 2 by expanding its capacity in ways that deterred entry.189 In its
Section 1 cases during this period, the Supreme Court likewise condemned a wide range of
conduct as per se illegal.190
The 1970s witnessed a marked shift in theory and doctrine. As discussed, beginning in the 1950s,
lawyers and economists affiliated with what came to be known as the Chicago School challenged
much of prevailing antitrust thinking.191 Chicago School scholars criticized SCP theories on a
variety of grounds. Among other things, they argued that markets tend to self-correct; that high
levels of concentration often reflect growth by the most efficient firms; and that many business
practices that attracted antitrust scrutiny had efficiency-based rationales.192 The Chicago School’s
most influential contribution, however, was its prescription that antitrust should be limited to
promoting economic welfare.193 An antitrust system that instead committed itself to a series of
often-conflicting social objectives, Chicago School scholars claimed, offered no principled
method for distinguishing anticompetitive behavior from permissible conduct.194
Chicago’s empirical claims did not go unchallenged. Scholars working in the “Post-Chicago”
tradition generally embraced the Chicago School’s focus on economic goals, but developed
theories of anticompetitive harm that were not present in the Chicago literature.195 Many of these
Post-Chicago models highlighted the possibility that dominant firms could employ strategic
behavior to raise their rivals’ costs, relying heavily on game theory.196 Another group of
academics from the so-called “modern Harvard School” tended to fall somewhere between the
Chicago School and the ideology of mid-20th century antitrust, focusing on the administrability
of antitrust doctrine and the institutional limitations of courts.197 Like Post-Chicago scholars, the
modern Harvard School endorsed the Chicago view that the ultimate purpose of the antitrust laws
is to promote economic welfare.198 The three approaches differ primarily in their empirical claims
about market functioning and the competence of courts to remedy market failures.199
In general, the Chicago School and the modern Harvard School have had the greatest impact on
the shape of current doctrine.200 Since the 1970s, the Supreme Court has overturned several

189 Id. at 431 (“It was not inevitable that [Alcoa] should always anticipate increases in the demand for ingot and be
prepared to supply them. Nothing compelled it to keep doubling and redoubling its capacity before others entered the
field. It insists that it never excluded competitors; but we can think of no more effective exclusion than progressively to
embrace each new opportunity as it opened, and to face every newcomer with new capacity already geared into a great
organization, having the advantage of experience, trade connections and the elite of personnel.”).
190 E.g., United States v. Topco Assocs., Inc., 405 U.S. 596 (1972) (joint venture involving territorial restraints);
Albrecht v. Herald Co., 390 U.S. 145 (1968) (maximum resale price maintenance); United States v. Arnold, Schwinn &
Co., 388 U.S. 365 (1967) (vertical territorial restraints); International Salt Co., Inc. v. United States, 332 U.S. 392
(1947) (tying).
191 See, e.g., Herbert Hovenkamp & Fiona Scott Morton, Framing the Chicago School of Antitrust Analysis, 168 U. PA.
L. REV. 1843 (2020).
192 VAN DEN BERGH, supra note 183, at 45-49.
193 See Richard Schmalensee, Thoughts on the Chicago Legacy in U.S. Antitrust, in HOW THE CHICAGO SCHOOL
OVERSHOT THE MARK: THE EFFECT OF CONSERVATIVE ECONOMIC ANALYSIS ON U.S. ANTITRUST 11, 12-14 (Robert
Pitofsky ed. 2008); RICHARD A. POSNER, ANTITRUST LAW ix (2d ed. 2001).
194 Schmalensee, supra note 193, at 12.
195 Christopher S. Yoo, The Post-Chicago Antitrust Revolution: A Retrospective, 168 U. PA. L. REV. 2145, 2160-61
(2020).
196 Id.
197 HOVENKAMP, ANTITRUST ENTERPRISE, supra note 177, at 37-38, 45-56.
198 Id. at 31.
199 Id.
200 See Kovacic, supra note 70.
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decisions establishing per se Section 1 liability for certain categories of conduct201 and
established restrictive standards for various types of monopolization claims.202 Similarly, the
lower courts and the antitrust agencies have de-emphasized structural merger analysis in favor of
more detailed inquiries into the competitive effects of individual transactions.203
Modern antitrust doctrine has also abandoned explicit consideration of “non-economic” goals like
small business protectionism and the sociopolitical effects of concentrated economic power.204
Since the 1970s, the Supreme Court has repeatedly described the antitrust laws as being
principally concerned with the economic welfare of consumers.205 This proposition—often called
the “consumer welfare standard”—has generated an enormous amount of scholarly attention,
especially in recent years. While there is disagreement about what the standard does and should
mean in practice,206 contemporary doctrine clearly recognizes economic welfare as the lodestar of
antitrust analysis.207
Over the past decade or so, this economic orientation has been criticized by a group of academics
and policymakers often described as “Neo-Brandeisians.” Members of this movement have
criticized much of existing antitrust doctrine as unduly permissive and called for increased

201 Leegin Creative Leather Prods., Inc. v. PSKS, Inc., 551 U.S. 877 (2007) (minimum resale price maintenance); State
Oil Co. v. Khan, 522 U.S. 3 (1997) (maximum resale price maintenance); Cont’l T.V., Inc. v. GTE Sylvania Inc., 433
U.S. 36 (1977) (vertical territorial restraints).
202 Pac. Bell Tel. Co. v. linkLine Commc’ns, Inc., 555 U.S. 438 (2009) (price squeezes); Weyerhaeuser Co. v.
Ross-Simmons Hardwood Lumber Co., 549 U.S. 312 (2007) (predatory buying); Verizon Commc’ns Inc. v. L. Offs. of
Curtis V. Trinko, LLP, 540 U.S. 398 (2004) (refusals to deal); Brooke Grp. Ltd. v. Brown & Williamson Tobacco
Corp., 509 U.S. 209 (1993) (predatory pricing).
203 See, e.g., United States v. Baker Hughes, Inc., 908 F.2d 981 (D.C. Cir. 1990); HORIZONTAL MERGER GUIDELINES,
supra note 49, at § 5.3.
204 See, e.g., Joshua D. Wright & Douglas H. Ginsburg, The Goals of Antitrust: Welfare Trumps Choice, 81 FORDHAM
L. REV. 2405, 2405-06 (2013).
205 NCAA v. Alston, 141 S. Ct. 2141, 2151 (2021); Ohio v. Am. Express Co., 138 S. Ct. 2274, 2284 (2018); Leegin
Creative Leather Prods., Inc. v. PSKS, Inc., 551 U.S. 877, 886 (2007); Weyerhaeuser Co. v. Ross-Simmons Hardwood
Lumber Co., 549 U.S. 312, 324 (2007); Brooke Grp. Ltd. v. Brown & Williamson Tobacco Corp., 509 U.S. 209, 224
(1993); Jefferson Par. Hosp. Dist. No. 2 v. Hyde, 466 U.S. 2, 15 (1984); NCAA v. Bd. of Regents of Univ. of Okla.,
468 U.S. 85, 107 (1984); Reiter v. Sonotone Corp., 442 U.S. 330, 343 (1979); see also John B. Kirkwood & Robert H.
Lande, The Fundamental Goal of Antitrust: Protecting Consumers, Not Increasing Efficiency, 84 NOTRE DAME L. REV.
191, 219-24 (2008) (collecting lower court cases embracing the consumer-welfare standard).
206 There are several issues here. First, Robert Bork—an influential Chicago School academic and later a federal
judge—used the term “consumer welfare” to refer to a “total welfare” standard that focuses on the sum of producer and
consumer surplus, while many commentators instead use the term “consumer welfare” to refer to a standard that
focuses only on consumer surplus. See, e.g., Barak Y. Orbach, The Antitrust Consumer Welfare Paradox, 7 J.
COMPETITION L. & ECON. 133, 142-49 (2010). Both versions of the “consumer welfare” standard have supporters. See
Roger D. Blair & D. Daniel Sokol, Welfare Standards in U.S. and E.U. Antitrust Enforcement, 81 FORDHAM L. REV.
2497 (2013) (favoring a total-welfare standard); Steven C. Salop, Question: What Is the Real and Proper Antitrust
Welfare Standard? Answer: The True Consumer Welfare Standard, 22 LOY. CONSUMER L. REV. 336 (2010) (favoring a
consumer-surplus standard). Second, the extent to which the consumer-welfare standard recognizes harms that sellers
suffer from anticompetitive conduct remains the subject of ongoing discussion. See, e.g., Herbert J. Hovenkamp, Is
Antitrust’s Consumer Welfare Principle Imperiled?, 45 J. CORP. L. 101, 113-15 (2019); C. Scott Hemphill & Nancy L.
Rose, Mergers That Harm Sellers, 127 YALE L.J. 2078 (2018). Third, some commentators have argued that the
consumer-welfare standard does not represent an accurate description of current antitrust doctrine for other reasons.
E.g., Gregory J. Werden, Antitrust’s Rule of Reason: Only Competition Matters, 79 ANTITRUST L.J. 713, 713, 743
(2014) (arguing that “the rule of reason focuses solely on how a challenged restraint affects the competitive process,”
and that antitrust protects consumer welfare by protecting the “competitive process”); see also DEVLIN, supra note 10,
at 254-68 (contending that the consumer-welfare standard is descriptively inaccurate in several respects).
207 See, e.g., ANTITRUST MODERNIZATION COMM’N, REPORT AND RECOMMENDATIONS 35 (Apr. 2007) (“For the last few
decades courts, agencies, and antitrust practitioners have recognized consumer welfare as the unifying goal of antitrust
law.”).
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attention to some of the “non-economic” goals that played a more prominent role in earlier
periods of antitrust history.208 The Neo-Brandeisian movement’s prescriptions are discussed in
greater detail below.209
The Big Tech Firms: A Summary of Selected
Antitrust Allegations
The Big Tech firms have achieved tremendous financial success. As of the publication of this
report, the combined market capitalization of Meta, Alphabet (Google’s parent), Amazon, and
Apple is more than $6.6 trillion—a figure that exceeds the value of all but the largest national
equity markets.210
While some have emphasized the quality of the firms’ offerings as the primary driver of their
ascent,211 others have alleged that Big Tech has obtained and cemented monopoly power through
anticompetitive conduct.212
This section of the report reviews selected antitrust allegations against the Big Tech firms.
Meta Platforms
Meta describes itself as a company that builds technology that “helps people connect, find
communities, and grow businesses.”213 More specifically, Meta offers a “family of apps” related
to social networking and messaging.214 This family of apps consists of
• Facebook (a social network);
• Instagram (a photo-sharing platform);
• Messenger (a messaging app for Facebook users); and
• WhatsApp (a messaging app).215

208 The Neo-Brandeisian movement derives its name from Louis Brandeis, a former Associate Justice of the Supreme
Court who was also a proponent of vigorous antitrust enforcement and a critic of large corporations. See Lina M. Khan,
The New Brandeis Movement: America’s Antimonopoly Debate, 9 J. EURO. COMPETITION L. & PRACTICE 131 (2018).
209 See infra “Revisiting the Goals of Antitrust: The Neo-Brandeisian Movement.”
210 See Largest Companies by Market Cap, COMPANIESMARKETCAP (last visited Nov. 6, 2023),
https://companiesmarketcap.com/; Largest Stock Exchange Operators Worldwide as of October 2022, By Market
Capitalization of Listed Companies, STATISTA (Jan. 2023), https://www.statista.com/statistics/270126/largest-stock-
exchange-operators-by-market-capitalization-of-listed-companies/; Market Capitalization of Listed Domestic
Companies, THE WORLD BANK (last visited Mar. 15, 2023), https://data.worldbank.org/indicator/CM.MKT.LCAP.CD.
211 E.g., Investigation into the State of Competition in Digital Markets, Subcomm. on Antitrust, Commercial, & Admin.
L. of H. Comm. on the Judiciary (May 11, 2020) (statement of Randal C. Picker, James Parker Distinguished Service
Prof. of Law, The Univ. of Chi. L. Sch. at 34), https://picker.uchicago.edu/PickerHouseStatement.100.pdf.
212 E.g., HJC REPORT, supra note 11, at 12-17.
213 Meta Platforms, Inc., Annual Report (Form 10-K) at 7 (Feb. 2, 2023).
214 Id. Meta also produces augmented and virtual reality products via its Reality Labs division. Id. at 8.
215 Id. at 7.
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In October 2023, Meta reported that Facebook had 2.09 billion daily active users and 3.05 billion
monthly active users.216 The company’s family of apps reportedly features 3.14 billion daily
active people and 3.96 billion monthly active people.217
Allegations of Market Power
Some observers have argued that Meta possesses significant market power in the market for
social networking.218 The Federal Trade Commission (FTC) shares that view. In an ongoing
monopolization lawsuit, the Commission alleges that Meta has held monopoly power in the
market for “personal social networking services” (PSNS) since at least 2011.219 To support such
claims, Meta’s critics have argued that the firm has persistently maintained a large market share
and benefited from substantial entry barriers, including powerful network effects and high
switching costs.220
Others disagree. Meta has argued that it operates in a “dynamic, intensely competitive” industry
in which there are many substitutes for its services.221 In its litigation with the FTC, the firm has
criticized the Commission’s alleged PSNS market as unduly narrow insofar as it excludes rivals
like YouTube, TikTok, LinkedIn, and Twitter.222
Meta and some commentators have also rejected the notion that entry barriers have caused the
market to decisively tip in Meta’s favor.223 For example, observers have highlighted the ability of
differentiated firms like TikTok and Snapchat to rapidly gain scale despite Meta’s ostensible
network advantages.224
Allegations of Anticompetitive Conduct
Meta has also been accused of engaging in anticompetitive conduct. The FTC’s lawsuit contends
that Meta has maintained its dominant position through its 2012 acquisition of Instagram and its

216 Meta Platforms, Inc., Quarterly Report (Form 10-Q) at 35 (Oct. 26, 2023).
217 Id.
218 HJC REPORT, supra note 11, at 133; ONLINE PLATFORMS AND DIGITAL ADVERTISING: MARKET STUDY FINAL REPORT,
U.K. COMPETITION & MKTS AUTHORITY 146 (July 1, 2020), https://assets.publishing.service.gov.uk/media/
5fa557668fa8f5788db46efc/Final_report_Digital_ALT_TEXT.pdf [hereinafter “CMA REPORT”]; Fiona M. Scott
Morton & David C. Dinielli, Roadmap for an Antitrust Case Against Facebook, OMIDYAR NETWORK 11-15 (June
2020), https://www.omidyar.com/wp-content/uploads/2020/06/Roadmap-for-an-Antitrust-Case-Against-Facebook.pdf;
DIGITAL PLATFORMS INQUIRY: FINAL REPORT, AUSTRALIAN COMPETITION & CONSUMER COMM’N 9 (June 2019),
https://www.accc.gov.au/system/files/Digital%20platforms%20inquiry%20-%20final%20report.pdf [hereinafter
“ACCC REPORT”].
219 Substitute Amended Complaint for Injunctive and Other Equitable Relief ¶ 164, FTC v. Facebook, Inc., No.
1:20-cv-03590 (D.D.C. Sept. 8, 2021).
220 Id. ¶ 212; HJC REPORT, supra note 11, at 136-47; Scott Morton & Dinielli, supra note 218, at 11; ACCC REPORT,
supra note 218, at 58. The FTC and some commentators have also attempted to establish that Meta has monopoly
power with direct evidence, arguing that the firm has degraded the quality of its products without losing significant
numbers of users. Substitute Amended Complaint ¶¶ 205-09, FTC v. Facebook, Inc., No. 1:20-cv-03590 (D.D.C. Sept.
8, 2021); Dina Srinivasan, The Antitrust Case Against Facebook: A Monopolist’s Journey Towards Pervasive
Surveillance in Spite of Consumer’s Preference for Privacy, 16 BERKELEY BUS. L.J. 39 (2019).
221 Memorandum in Support of Facebook, Inc.’s Motion to Dismiss FTC’s Complaint at 11, FTC v. Facebook, Inc., No.
1:20-cv-03590 (D.D.C. Mar. 10, 2021).
222 Id. at 10.
223 Id. at 13-16; Herbert J. Hovenkamp, Selling Antitrust, 73 HASTINGS L.J. 1621, 1623 (2022) [hereinafter
“Hovenkamp, Selling Antitrust”]; Jay Ezrielev & Genaro Marquez, Interoperability: The Wrong Prescription for
Platform Competition, COMPETITION POLICY INT’L ANTITRUST CHRON. 8, 13-14 (June 2021).
224 Hovenkamp, Selling Antitrust, supra note 223, at 1623; Ezrielev & Marquez, supra note 223, at 8.
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2014 acquisition of WhatsApp.225 The Commission argues that Meta’s Instagram purchase
allowed it to neutralize a rapidly growing competitive threat, giving the firm control over what
became two of the most popular social networks in the world.226 The FTC also contends that
Meta’s acquisition of WhatsApp preserved its monopoly by preventing WhatsApp from entering
the PSNS market.227
Besides targeting Meta’s major acquisitions, the FTC and some commentators have criticized the
company’s treatment of software developers.228 These allegations involve access to Facebook
Platform—an initiative whereby Meta encouraged developers to create apps that interoperate with
Facebook.229 As part of this initiative, Meta provided software developers with application
programming interfaces (APIs) and other tools that allowed them to access certain Facebook data
and functionalities.230 According to the FTC, Facebook Platform ultimately became key
infrastructure for app developers because of Facebook’s large user base.231 The Commission’s
lawsuit alleges that Meta leveraged control of this infrastructure to preserve its monopoly,
requiring developers that participated in Facebook Platform to refrain from creating apps that
would compete with Facebook products.232
Meta has denied engaging in anticompetitive conduct. The company has argued that its Instagram
acquisition allowed it to invest resources and expertise in a young startup, hastening the small
firm’s growth.233 Meta has also defended its WhatsApp purchase, arguing that the FTC has failed
to present evidence that WhatsApp would have likely entered social networking absent the
acquisition.234 Finally, Meta has argued that its policies governing access to Facebook Platform—
which it has since revised—were lawful under duty-to-deal doctrine.235
As of the publication of this report, the FTC’s monopolization case against Meta is in discovery, a
pre-trial stage of litigation in which the parties develop evidence that can be used at trial.
Although the district court dismissed the agency’s initial complaint for failing to plausibly allege
monopoly power,236 the court ultimately allowed the case to proceed after concluding that the
Commission’s amended complaint was sufficiently plausible to survive a motion to dismiss.237

225 Substitute Amended Complaint ¶¶ 77-129, FTC v. Facebook, Inc., No. 1:20-cv-03590 (D.D.C. Sept. 8, 2021); see
also HJC REPORT, supra note 11, at 150-60 (arguing that Meta’s Instagram and WhatsApp acquisitions harmed
competition).
226 Substitute Amended Complaint ¶¶ 80-106, FTC v. Facebook, Inc., No. 1:20-cv-03590 (D.D.C. Sept. 8, 2021).
227 Id. ¶¶ 107-29.
228 Id. ¶¶ 130-163; HJC REPORT, supra note 11, at 166-70; Scott Morton & Dinielli, supra note 218, at 24-25.
229 Substitute Amended Complaint ¶¶ 25-42, FTC v. Facebook, Inc., No. 1:20-cv-03590 (D.D.C. Sept. 8, 2021).
230 Id.
231 Id. ¶ 131.
232 Id. ¶ 133. A group of state attorneys general made similar claims in a lawsuit filed in 2020. New York v. Facebook,
Inc., 549 F. Supp. 3d 6 (D.D.C. 2021). A federal district court dismissed that lawsuit in 2021, concluding that the
claims challenging Facebook’s acquisitions were barred by the doctrine of laches (which precludes lawsuits filed after
an unreasonable delay); that Facebook’s general policy of withholding APIs from rival developers was not
exclusionary standing alone; and that specific refusals to deal occurred too long ago to support injunctive relief. Id. at
27-31, 34.
233 Memorandum in Support of Facebook, Inc.’s Motion to Dismiss FTC’s Complaint at 29-30, FTC v. Facebook, Inc.,
No. 1:20-cv-03590 (D.D.C. Oct. 4, 2021).
234 Id. at 24.
235 Id. at 35.
236 FTC v. Facebook, Inc., 560 F. Supp. 3d 1, 4 (D.D.C. 2021).
237 FTC v. Facebook, Inc., 581 F. Supp. 3d 34, 43-52 (D.D.C. 2022). While the district court has allowed the FTC’s
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Google
Google is a ubiquitous presence in the digital economy. The firm began as an internet search
company and is now also a major player in digital advertising, mobile operating systems, app
distribution, digital maps, email, and web browsing.238 The following subsections discuss antitrust
allegations involving Google’s conduct related to online search, mobile operating systems and
app distribution, and digital advertising.
Online Search
Allegations of Market Power
Some commentators have argued that Google has significant market power in the market for
general online search.239 The DOJ agrees. In an ongoing monopolization lawsuit, the DOJ
contends that Google has monopoly power in the market for “general search services” based on
an alleged market share of 88% and the presence of substantial entry barriers, including
economies of scale.240 The DOJ has also alleged monopolization of separate markets for “general
search text advertising” and “search advertising.”241
For its part, Google has claimed that it operates in a “highly competitive environment” and faces
a “vast array of competitors.”242 The company also argues that, for particular search queries, it
competes against a range of firms—such as Amazon, eBay, and Yelp—that would not fall within
a market for general search services.243
Allegations of Anticompetitive Conduct
Search Distribution
The DOJ’s monopolization lawsuit contends that Google has maintained its search monopoly
through exclusionary agreements with firms that control search distribution.244 The agreements
make Google the default search engine on various products in exchange for a share of Google’s
advertising revenue.245

challenge to Meta’s Instagram and WhatsApp acquisitions to proceed, it dismissed the agency’s claims involving
access to Facebook Platform. Id. at 57-59. In rejecting the latter claims, the court concluded that Meta had no general
duty to allow potential rivals to access Facebook Platform. Id. at 58-59. Although the court indicated that specific
refusals may be actionable, it held that the refusals alleged by the FTC could not justify injunctive relief because they
occurred in 2013 and were not ongoing. Id.
238 HJC REPORT, supra note 11, at 174.
239 CMA REPORT, supra note 218, at 73; HJC REPORT, supra note 11, at 176-82; ACCC REPORT, supra note 218, at 58;
Google Search (Shopping) (Case AT.39740), Commission Decision ¶ 271 (June 27, 2017),
https://ec.europa.eu/competition/antitrust/cases/dec_docs/39740/39740_14996_3.pdf [hereinafter “EC Google
Shopping Decision”].
240 Amended Complaint ¶¶ 92-96, United States v. Google LLC, No. 1:20-cv-03010 (D.D.C. Jan. 15, 2021).
241 Memorandum Opinion at 5, United States v. Google LLC, No. 1:20-cv-03010 (D.D.C. Aug. 4, 2023).
242 HJC REPORT, supra note 11, at 179.
243 Id.
244 Amended Complaint ¶ 4, United States v. Google LLC, No. 1:20-cv-03010 (D.D.C. Jan. 15, 2021). A group of state
attorneys general has made similar allegations in a case that has been consolidated with the DOJ’s lawsuit.
Memorandum Opinion at 5, United States v. Google LLC, No. 1:20-cv-03010 (D.D.C. Aug. 4, 2023).
245 Memorandum Opinion at 3, United States v. Google LLC, No. 1:20-cv-03010 (D.D.C. Aug. 4, 2023).
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The lawsuit focuses on Google’s agreements with two categories of counterparties: (1) browser
developers, and (2) manufacturers and wireless carriers that sell devices running the Android
mobile operating system, which Google acquired in 2005.246
Under Google’s agreements with browser developers—primarily Apple and Mozilla—the
developers have agreed to make Google the default search engine for all search access points on
their browsers in exchange for payments from Google.247
The DOJ’s allegations regarding device manufacturers and wireless carriers involve two types of
agreements. One set of contracts requires manufacturers to preinstall Google Search and place an
associated search widget on device home screens as conditions of licensing other proprietary
Google apps.248 Under another set of agreements, manufacturers and wireless carriers commit to
make Google the only preinstalled search engine on covered devices and the default for all search
access points in exchange for payments from Google.249
In its lawsuit, the DOJ contends that Google’s agreements amount to exclusive contracts that
foreclose substantial channels of search distribution, depriving rivals of the scale needed to serve
as effective competitors.250
Google has made several arguments in response. While Google concedes that its revenue-sharing
agreements with manufacturers and carriers require exclusivity, it has denied that its contracts
with browser developers and its Android licensing agreements amount to exclusive dealing.251
The browser agreements are not exclusive, Google contends, because they do not prevent
developers from promoting rival search engines and users can change a browser’s default search
engine.252 Similarly, Google argues that its Android licensing agreements do not prohibit
manufacturers from preinstalling rival search apps or browsers.253
Google further maintains that the relevant agreements would not be anticompetitive even if they
did require exclusivity. Rather, Google claims that it has successfully competed with rivals to
secure the challenged agreements with browser developers, who have chosen Google as their
default search engine based on considerations of quality and price.254 Google claims that this
“competition for the contract” is the type of merits competition that antitrust encourages.255
Google also denies that its Android agreements result in substantial foreclosure, arguing that the
appropriate measure of foreclosure requires an analysis of consumer behavior absent the
agreements, rather than the percentage of the market covered by those agreements.256 Because
few consumers would switch from Google to another search engine if the challenged agreements
did not exist, Google argues, the agreements do not substantially foreclose rivals.257

246 Id.
247 Id. at 10.
248 Id. at 13.
249 Id. at 13-14.
250 Id. at 30.
251 Id.
252 Id. at 31-33.
253 Id. at 40.
254 Id. at 35-36.
255 Id. at 35.
256 Id. at 42-43.
257 Id. at 43. In its motion for summary judgment, Google argued that the plaintiffs’ expert evidence indicated that
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In August 2023, a federal district court allowed the claims discussed above to proceed, denying in
part Google’s motion for summary judgment.258 The court concluded that there were disputed
issues of material fact as to whether Google’s browser agreements and Android licensing
agreements were de facto exclusive, including disagreement over the competitive significance of
default status.259 The court likewise held that Google’s “competition for the contract” defense and
the appropriate measure of foreclosure raised issues that could not be resolved on summary
judgment.260
Foreclosure metrics are likely to be a key issue at trial, which began in September 2023 and is
ongoing as of the publication of this report. While courts regularly look to the share of
distribution covered by exclusive contracts in evaluating foreclosure, some commentators have
advocated alternative approaches, including the type of counterfactual analysis that Google
proposes.261 The choice between alternative metrics may present the court with a trade-off: while
Google’s preferred methodology arguably involves a more accurate assessment of the competitive
impact of the challenged agreements, the DOJ’s simpler approach may be more manageable and
appears to be more firmly rooted in the case law.262
The issue of procompetitive justification may also prove significant. The DOJ’s case relies
heavily on the importance of scale in improving search-engine quality. If Google can establish
that it has not exhausted the relevant scale economies, those economies may constitute a
procompetitive justification for its distribution agreements.263 To the extent that the court accepts
this justification, the DOJ may need to prove that Google can secure those economies through
less restrictive means or that the anticompetitive effects of the agreements outweigh their
benefits.
Self-Preferencing
Commentators and some foreign regulators have also argued that Google has leveraged its
dominance in general search to favor its own vertical offerings. For example, the HJC Report
concluded that Google has adjusted its search algorithms to automatically elevate some of
Google’s vertical services, like its video-sharing platform YouTube, in search results.264

(1) approximately 1% of all search queries would shift from Google to non-Google search engines if manufacturers and
carriers adopted a “choice screen” allowing consumers to select their own default search engines (a remedy
implemented in an EU competition case involving Google Search), and (2) approximately 11.6% to 13.5% of search
queries would shift from Google to non-Google search engines if a rival search engine was the exclusive preinstalled
default on Android devices. Id. at 43.
258 Id. at 60.
259 Id. at 34-35.
260 Id. at 36-37, 43. The court granted Google’s motion for summary judgment with respect to certain other claims,
some brought by the DOJ and some brought by a group of state attorneys general in a case that has been consolidated
with the DOJ lawsuit. Id. at 60.
261 Joshua D. Wright, Moving Beyond Naïve Foreclosure Analysis, 19 GEO. MASON L. REV. 1163, 1177-81 (2012).
262 Id. at 1177 (observing that “most courts” rely on the share of distribution covered by a challenged agreement to
evaluate foreclosure, with “some occasional modifications”).
263 See Thom Lambert, Why the Federal Government’s Antitrust Case Against Google Should—and Likely Will—Fail,
TRUTH ON THE MARKET (Dec. 18, 2020), https://truthonthemarket.com/2020/12/18/why-the-federal-governments-
antitrust-case-against-google-should-and-likely-will-fail/.
264 HJC REPORT, supra note 11, at 187-92.
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This type of self-preferencing prompted the European Commission—which enforces European
Union competition law—to fine Google €2.42 billion in 2017 for giving prominent placement to
its comparison-shopping service and demoting rival services in search results.265
The FTC investigated similar allegations of self-preferencing involving Google Search in 2012,
but concluded that it had not found sufficient evidence of an antitrust violation.266 The agency
determined that Google’s favorable placement of its own verticals could plausibly be viewed as
an improvement in the quality of Google’s search product.267 The Commission also did not find
sufficient evidence that Google had manipulated its search algorithms to unfairly disadvantage
rival vertical websites.268
Mobile Operating Systems and App Distribution
Allegations of Market Power
Mobile Operating Systems
In addition to operating a major search engine, Google controls Android—a leading mobile
operating system. Android and Apple’s iOS represent the two dominant mobile operating systems,
together accounting for 99% of the market.269 Because Apple does not license iOS to other device
manufacturers, Android by itself occupies a very large share of the market for licensable mobile
operating systems—by some estimates, 99% of that market.270
Some commentators have argued that the market for licensable mobile operating systems is the
relevant one for antitrust purposes, based on factors like high switching costs.271 Private plaintiffs
and (in a separate case that has been settled) a group of state attorneys general have argued that
Google has monopoly power in this market based on the company’s dominant market share and
the presence of substantial entry barriers, such as network effects and research and development
costs.272
Google denies such allegations, arguing that consumers “can and do switch and multi-home
among and between mobile and nonmobile ecosystems, including between Android and iOS.”273

265 EC Google Shopping Decision, supra note 239.
266 Statement of the Federal Trade Commission Regarding Google’s Search Practices, In the Matter of Google Inc., No.
111-0163 (FTC Jan. 3, 2013).
267 Id. at 3.
268 Id.
269 HJC REPORT, supra note 11, at 100-02.
270 First Amended Complaint ¶ 7, State of Utah et al. v. Google LLC, No. 3:21-cv-05227 (N.D. Cal. Nov. 1, 2021); see
also Second Amended Complaint for Injunctive Relief ¶¶ 16, 55, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022) (alleging a market share of “over 95%”).
271 HJC REPORT, supra note 11, at 102. In a 2018 enforcement action, the European Commission concluded that
competition from Apple does not sufficiently constrain Google for similar reasons. See Press Release, Euro. Comm’n,
Antitrust: Commission Fines Google €4.34 Billion for Illegal Practices Regarding Android Mobile Devices to
Strengthen Dominance of Google’s Search Engine (July 18, 2018),
https://ec.europa.eu/commission/presscorner/detail/en/IP_18_4581.
272 Second Amended Complaint for Injunctive Relief ¶¶ 55-64, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022); First Amended Complaint ¶¶ 44-58, State of Utah et al. v. Google LLC, No. 3:21-cv-05227
(N.D. Cal. Nov. 1, 2021).
273 Defendants’ Answers and Defenses to State of Utah et al. First Amended Complaint ¶ 55-56, No. 3:21-cv-05227
(N.D. Cal. Nov. 15, 2021); see also Defendants’ Answer, Defenses, and Counterclaims to Epic Games, Inc.’s Second
Amended Complaint for Injunctive Relief ¶¶ 55, 57, No. 3:20-cv-05671 (N.D. Cal. Dec. 1, 2022).
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Mobile App Distribution
Litigants have also contended that, through its Google Play Store, Google has market power in
certain markets related to mobile-app distribution. Some plaintiffs have defined the relevant
market as consisting of the distribution of apps to Android users.274 They allege that Google has
monopoly power in this market based on the Play Store’s market share of more than 90%, strong
network effects, high switching costs, and Google’s ability to charge a 30% commission on apps
purchased through the Play Store.275
Some plaintiffs have also argued in the alternative that Google has market power in a broader
market for mobile app distribution—that is, a market not limited to Android users.276 A group of
state attorneys general, for example, has argued that Google occupies a sizeable share of this
market, enjoys large profit margins, and benefits from formidable entry barriers.277
Google rejects these claims. It contends that consumers can use different platforms to access apps
and that “Apple and Google compete vigorously in the mobile operating system environment on
multiple dimensions, including innovation, price, privacy, and security.”278
In-App Payment Processing
Plaintiffs have further claimed that Google has monopoly power in a market for in-app payment
(IAP) processing for Android apps.279 They have based this claim on the Play Store’s large share
of the market for Android app distribution and Google’s requirement that software developers
using the Play Store also use Google’s IAP processor.280
As discussed, for many transactions, Google charges a 30% commission for IAP processing—a
rate that is considerably higher than those charged by other electronic payment processors.281

274 Second Amended Complaint for Injunctive Relief ¶¶ 68-72, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022); First Amended Complaint ¶¶ 63-73, State of Utah et al. v. Google LLC, No. 3:21-cv-05227
(N.D. Cal. Nov. 1, 2021).
275 Second Amended Complaint for Injunctive Relief ¶¶ 75-88, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022); First Amended Complaint ¶¶ 76-78, State of Utah et al. v. Google LLC, No. 3:21-cv-05227
(N.D. Cal. Nov. 1, 2021).
276 Second Amended Complaint for Injunctive Relief ¶ 73, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022); First Amended Complaint ¶¶ 79-81, State of Utah et al. v. Google LLC, No. 3:21-cv-05227
(N.D. Cal. Nov. 1, 2021).
277 First Amended Complaint ¶¶ 79-81, State of Utah et al. v. Google LLC, No. 3:21-cv-05227 (N.D. Cal. Nov. 1,
2021). The state attorneys general allege that Google’s share of this market in the United States exceeds 30 percent,
while its share of the global market (excluding China) is approximately 53% by revenue. Id. ¶ 80.
278 Defendants’ Answers, Defenses, and Counterclaims to Epic Games, Inc.’s Second Amended Complaint for
Injunctive Relief ¶ 80, No. 3:20-cv-05671 (N.D. Cal. Dec. 1, 2022).
279 Second Amended Complaint for Injunctive Relief ¶¶ 158-60, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022); First Amended Complaint ¶¶ 182-86, State of Utah et al. v. Google LLC, No. 3:21-cv-
05227 (N.D. Cal. Nov. 1, 2021).
280 Second Amended Complaint for Injunctive Relief ¶¶ 158-60, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022); First Amended Complaint ¶¶ 182-86, State of Utah et al. v. Google LLC, No. 3:21-cv-
05227 (N.D. Cal. Nov. 1, 2021).
281 Second Amended Complaint for Injunctive Relief ¶ 160, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022). In March 2021, Google announced plans to lower its commissions from 30% to 15% for the
first $1 million in revenue that developers earn using Google’s billing system. Manish Singh, Google Play Drops
Commissions to 15% from 30%, Following Apple’s Move Last Year, TECHCRUNCH (Mar. 16, 2021),
https://techcrunch.com/2021/03/16/google-play-drops-commissions-to-15-from-30-following-apples-move-last-year/.
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Google has denied possessing monopoly power related to IAP processing.282
Allegations of Anticompetitive Conduct
Mobile App Distribution
Google has also been accused of engaging in a variety of anticompetitive activities involving app
distribution. Some of the allegations are reviewed below.
• Google has allegedly imposed technical barriers that make it difficult for
consumers to download Android apps from sources other than the Google Play
Store—a practice commonly known as “sideloading.”283 Litigants have claimed
that sideloading Android apps entails a complicated process that includes several
security warnings discouraging such actions.284 Google has also been accused of
making it unnecessarily difficult to update sideloaded apps.285
• Google has allegedly barred software developers from distributing competing
app stores through the Play Store.286
• Google has allegedly required mobile device manufacturers that license Android
and certain other key Google services to preinstall the Google Play Store on their
devices.287 Plaintiffs have argued that this preinstallation requirement harms
competition by giving the Play Store an advantage over other app stores.288
• Google has allegedly required device manufacturers that offer the Play Store and
other “must-have” Google services to refrain from selling devices that run
“Android forks”—modified versions of Android that Google has not approved.289
Plaintiffs argue that these restrictions have stifled the development of alternative
versions of Android that would be free from some of the restrictions on app
distribution discussed above.290
• Google has allegedly entered into revenue-sharing agreements that deter device
manufacturers from developing competing app stores.291 The challenged
agreements give device manufacturers a share of Google’s advertising and Play
Store revenue from the devices they sell in exchange for a commitment to refrain
from competing against the Play Store.292

282 Defendants’ Answers, Defenses, and Counterclaims to Epic Games, Inc.’s Second Amended Complaint for
Injunctive Relief ¶ 158, No. 3:20-cv-05671 (N.D. Cal. Dec. 1, 2022); Defendants’ Answers and Defenses to State of
Utah et al. First Amended Complaint ¶ 182, No. 3:21-cv-05227 (N.D. Cal. Nov. 15, 2021).
283 First Amended Complaint ¶¶ 83-95, State of Utah et al. v. Google LLC, No. 3:21-cv-05227 (N.D. Cal. Nov. 1,
2021).
284 Id.
285 Id. ¶ 96.
286 Id. ¶¶ 107-10.
287 Id. ¶¶ 124-25.
288 Id. ¶ 125.
289 Id. ¶¶ 105-06.
290 Id.
291 Id. ¶¶ 130-35.
292 Id.
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Google has either denied engaging in the relevant conduct or rejected the contention that the
alleged conduct is anticompetitive.293
In-App Payment Processing
Plaintiffs have also accused Google of engaging in anticompetitive conduct in the market for
Android IAP processing. They have alleged that Google’s requirement that developers using the
Play Store also use Google’s IAP processor represents an unlawful tying arrangement.294
Digital Advertising
Allegations of Market Power
In addition to its search and app-distribution activities, Google is a major force in digital display
advertising markets.
In those markets, online ad publishers—like news websites—sell advertising space through
exchanges.295 Those ad exchanges conduct automated auctions in which advertisers can bid for ad
space.296
Intermediaries facilitate this process for both publishers and advertisers. Large publishers manage
their ad inventory using a type of software known as an ad server, which interfaces with ad
exchanges on behalf of publishers.297 On the other side of the market, advertisers employ
ad-buying tools, which connect them with ad exchanges and allow them to purchase ad space.298
Google operates in several segments of these markets via an ad exchange, a publisher ad server,
and ad-buying tools for advertisers.299
The DOJ and (in a separate lawsuit) a group of state attorneys general (state AGs) have argued
that Google has monopoly power in multiple ad-tech markets.
In January 2023, the DOJ filed a complaint alleging that Google has monopoly power in the
markets for publisher ad servers,300 ad exchanges,301 and advertiser ad networks.302
In a separate case, a group of state AGs has alleged that Google has monopoly power in the
markets for ad exchanges, ad servers, and ad-buying tools for small advertisers.303 The state AGs

293 Defendants’ Answers and Defenses to State of Utah et al. First Amended Complaint ¶¶ 83-89, 96, 105-110, 124-25,
130-35, No. 3:21-cv-05227 (N.D. Cal. Nov. 15, 2021).
294 Second Amended Complaint for Injunctive Relief ¶¶ 161-66, Epic Games, Inc. v. Google LLC, No. 3:20-cv-05671
(N.D. Cal. Nov. 17, 2022); First Amended Complaint ¶¶ 162-67, State of Utah et al. v. Google LLC, No. 3:21-cv-
05227 (N.D. Cal. Nov. 1, 2021).
295 Opinion and Order at 3, In re Google Digital Advertising Antitrust Litigation, No. 21-md-3010 (S.D.N.Y. Sept. 13,
2022).
296 Id.
297 Id. at 4.
298 Id. at 10-11.
299 Id. at 6-12.
300 Complaint ¶ 285, United States v. Google LLC, No. 1:23-cv-00108 (E.D. Va. Jan. 24, 2023).
301 Id. ¶ 296.
302 Id. ¶ 301.
303 Opinion and Order at 7-8, 11, In re Google Digital Advertising Antitrust Litigation, No. 21-md-3010 (S.D.N.Y.
Sept. 13, 2022).
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also contend that Google has monopoly power or a dangerous probability of acquiring monopoly
power in the market for ad-buying tools for large advertisers.304
In September 2022, a federal district court concluded that the state AGs’ allegations of monopoly
power were sufficiently plausible to survive a motion to dismiss.305 In April 2023, a district court
likewise rejected Google’s motion to dismiss the DOJ’s ad-tech lawsuit.306
Allegations of Anticompetitive Conduct
The DOJ and state AG lawsuits contend that Google has engaged in a range of anticompetitive
practices in several digital-advertising markets, allowing it to obtain and cement a dominant
position across the ad-tech stack.
The DOJ’s lawsuit claims that, in the early 2000s, Google’s ad-buying tools occupied a dominant
position on the advertiser side of the ad-tech market.307 Then, in 2008, Google acquired a firm
called DoubleClick, which operated a leading publisher ad server and a nascent ad exchange.308
After the DoubleClick acquisition, the DOJ contends, Google leveraged its position across the
ad-tech chain to benefit its own properties. Among other things, the DOJ alleges that Google
made demand from its ad-buying tools available only through its ad exchange.309 Google also
allegedly required publishers to use its ad server to receive real-time bids from its ad exchange.310
The state AG ad-tech lawsuit makes similar allegations.311
In September 2022, a federal district court held that the state AGs had plausibly alleged tying
claims under Sections 1 and 2 of the Sherman Act based on their assertion that Google had
coerced publishers into using its ad server as a condition of receiving live bids from its ad
exchange.312
The DOJ and state AG lawsuits also target a program used by Google’s ad server that allegedly
gave Google’s ad exchange advantages over rival exchanges.313 Another set of accusations
involves programs under which Google allegedly manipulated bids from its advertiser clients in
ways that advantaged its ad exchange and publisher ad server.314

304 Id. at 11.
305 Id. at 19, 34-35.
306 Order, United States v. Google LLC, No. 1:23-cv-00108 (E.D. Va. Apr. 28, 2023).
307 Complaint ¶¶ 11-13, United States v. Google LLC, No. 1:23-cv-00108 (E.D. Va. Jan. 24, 2023).
308 Id. ¶ 16. The FTC declined to challenge Google’s DoubleClick acquisition at the time. Press Release, Fed. Trade
Comm’n, Federal Trade Commission Closes Google/DoubleClick Investigation (Dec. 20, 2007),
https://www.ftc.gov/news-events/news/press-releases/2007/12/federal-trade-commission-closes-googledoubleclick-
investigation.
309 Complaint ¶ 89, United States v. Google LLC, No. 1:23-cv-00108 (E.D. Va. Jan. 24, 2023).
310 Id. ¶ 104. According to the DOJ’s complaint, publishers could use Google’s ad exchange without using its ad server
by selling ad space based on historical—rather than real-time—prices. Id. The DOJ contends, however, that this was
not an attractive option because the resulting prices were often considerably lower than those received from real-time
bids. Id.
311 Opinion and Order at 18, In re Google Digital Advertising Antitrust Litigation, No. 21-md-3010 (S.D.N.Y. Sept. 13,
2022).
312 Id. at 16-20, 77-78.
313 Complaint ¶¶ 21, 120-25, United States v. Google LLC, No. 1:23-cv-00108 (E.D. Va. Jan. 24, 2023); Opinion and
Order at 44-50, In re Google Digital Advertising Antitrust Litigation, No. 21-md-3010 (S.D.N.Y. Sept. 13, 2022).
314 Complaint ¶¶ 24, 139, 161-62, United States v. Google LLC, No. 1:23-cv-00108 (E.D. Va. Jan. 24, 2023); Opinion
and Order at 50-55, In re Google Digital Advertising Antitrust Litigation, No. 21-md-3010 (S.D.N.Y. Sept. 13, 2022).
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Google maintains that its conduct is permissible under antitrust doctrine governing refusals to
deal, product design, and tying.315
The September 2022 district court decision in the state AG lawsuit concluded that the allegations
of anticompetitive harm from these activities were sufficiently plausible to survive a motion to
dismiss.316 As noted, the district court in the DOJ’s lawsuit also denied Google’s motion to
dismiss that case, which focused on the allegations of monopoly power.317
The Google ad-tech lawsuits are complex, and a full discussion of the relevant claims is beyond
the scope of this report.318 Most of the allegations nevertheless implicate a recurring theme in
discussions of antitrust and tech platforms: the leveraging of economic power to obtain and
solidify dominance across different markets.319
Amazon
Like Google, Amazon has expanded its remit over time. The company began as an online
bookseller, but now operates a leading e-commerce marketplace, a major cloud-computing
platform, a logistics network, and a television and film studio.320 The discussion below focuses on
the company’s e-commerce activities.
Allegations of Market Power
In a pending monopolization lawsuit, the FTC has alleged that Amazon has monopoly power in
two markets: the “online superstore” market and the “online marketplace services” market.321 The
FTC argues that “online superstores”—which are distinguished based on the breadth and depth of
their product offerings—are not reasonably interchangeable with other online stores because
consumers’ overall shopping costs would increase “dramatically” if they tried to replace online
superstores by shopping at several different online stores with more limited offerings.322
Brick-and-mortar stores are not adequate substitutes for online superstores, the complaint alleges,
because of the convenience, wider product selection, and personalized shopping experience
offered by online superstores.323
The FTC also identifies a separate market for “online marketplace services” offered to sellers.324
The relevant services include access to a significant number of customers; the ability to create

315 Reply Memorandum of Law in Further Support of Google LLC’s Motion to Dismiss Counts I through IV of State
Plaintiffs’ Third Amended Complaint at 16-30, In re Google Digital Advertising Antitrust Litigation, No. 21-md-3010
(S.D.N.Y. May 5, 2022).
316 Opinion and Order at 44-55, In re Google Digital Advertising Antitrust Litigation, No. 21-md-3010 (S.D.N.Y. Sept.
13, 2022).
317 Order, United States v. Google LLC, No. 1:23-cv-00108 (E.D. Va. Apr. 28, 2023).
318 For a more detailed discussion of the DOJ’s lawsuit, see CRS Legal Sidebar LSB10956, The DOJ’s Ad Tech
Antitrust Case Against Google: A Brief Overview, by Alexander H. Pepper & Jay B. Sykes.
319 See generally Patrick F. Todd, Digital Platforms and the Leverage Problem, 98 NEB. L. REV. 486 (2019).
320 HJC REPORT, supra note 11, at 247.
321 Complaint ¶¶ 121, 184, FTC v. Amazon.com, Inc., No. 2:23-cv-01495 (W.D. Wash. Sept. 26, 2023).
322 Id. ¶ 148.
323 Id. ¶¶ 140-47.
324 Id. ¶ 184. During an investigation that began in November 2020, the European Commission preliminarily concluded
that Amazon occupied a dominant position in certain European markets for the provision of online marketplace
services to third-party sellers. Press Release, Euro. Comm’n, Antitrust: Commission Accepts Commitments by Amazon
Barring it From Using Marketplace Seller Data, and Ensuring Equal Access to Buy Box and Prime (Dec. 20, 2022),
https://ec.europa.eu/commission/presscorner/detail/en/ip_22_7777 [hereinafter “Amazon EC Commitments”].
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and maintain pages with product information; and the ability to display customer reviews to
shoppers.325 The complaint alleges that “online marketplace services” are not reasonably
interchangeable with selling as a vendor to online or offline retail stores, which typically involves
wholesale pricing and transfer of title to the relevant products.326
The FTC’s complaint follows similar lawsuits, including an action filed by the D.C. Attorney
General (D.C. AG) under D.C. law and another by a putative class of consumers under the
Sherman Act.327 The D.C. AG’s complaint alleged that Amazon has monopoly power among
online marketplaces,328 while the consumer lawsuit contends that Amazon has monopoly power in
a retail e-commerce market and several e-commerce submarkets for specific products.329
In 2022, the Superior Court of the District of Columbia dismissed the D.C. AG lawsuit on several
grounds, including a failure to plausibly allege monopoly power.330 The D.C. AG has appealed
that decision.331 In contrast, a federal district court has denied Amazon’s motion to dismiss the
consumer lawsuit, concluding that the plaintiffs plausibly alleged monopoly power, in addition to
rule-of-reason claims under Section 1 of the Sherman Act.332
Amazon’s alleged monopoly power will likely be litigated vigorously. In identifying an “online
superstore” market, the FTC appears to be alleging a “cluster” market that consists of a vast array
of noncompeting goods.333 Courts have recognized cluster markets in other contexts. For
example, groups of noncompeting financial and medical services have been deemed to be
relevant antitrust markets in cases involving banks and hospitals.334 In another case, the Supreme
Court concluded that the relevant market consisted of a package of centrally monitored alarm
services.335
While some courts have recognized cluster markets based on considerations of administrative
convenience (i.e., where distinct markets face similar competitive conditions, obviating the need
for separate analyses), the FTC appears to rely on a different theory of clustering grounded in
“transactional complementarity.”336 Under this theory, a package of noncompeting goods or
services may qualify as a relevant antitrust market if a significant number of consumers would be
willing to pay supra-competitive prices for the convenience of receiving the goods or services as
a package.337 Commentators have also argued that economies of scope and network effects may

325 Complaint ¶ 185, FTC v. Amazon.com, Inc., No. 2:23-cv-01495 (W.D. Wash. Sept. 26, 2023).
326 Id. ¶¶ 191-97.
327 Frame-Wilson v. Amazon.com, Inc., 591 F. Supp. 3d 975 (2022); First Amended Complaint, District of Columbia v.
Amazon.com, Inc., No. 2021-CA-001775 (D.C. Super. Ct. Sept. 10, 2021).
328 First Amended Complaint ¶¶ 85-86, District of Columbia v. Amazon.com, Inc., No. 2021-CA-001775 (D.C. Super.
Ct. Sept. 10, 2021).
329 Frame-Wilson, 591 F. Supp. 3d at 989.
330 Order at 15-16, District of Columbia v. Amazon.com, Inc., No. 2021-CA-001775 (D.C. Super. Ct. Aug. 1, 2022).
331 Notice of Appeal, District of Columbia v. Amazon.com, Inc., No. 2021-CA-001775 (D.C. Super. Ct. Aug. 25,
2022).
332 Frame-Wilson, 591 F. Supp. 3d at 988-92.
333 See, e.g., Herbert Hovenkamp, Digital Cluster Markets, 2022 COLUM. BUS. L. REV. 246 (2022) [hereinafter
“Hovenkamp, Digital Cluster Markets”].
334 United States v. Philadelphia Nat’l Bank, 374 U.S. 321, 356 (1963); ProMedica Health Sys., Inc. v. FTC, 749 F.3d
559, 566-67 (6th Cir. 2014).
335 United States v. Grinnell Corp., 384 U.S. 563, 572 (1966).
336 See ProMedica Health Sys., Inc., 749 F.3d at 567 (distinguishing this theory from the administrative-convenience
approach); Ian Ayres, Rationalizing Antitrust Cluster Markets, 95 YALE L.J. 109, 114-18 (1985) (developing the
transactional-complementarity theory of clustering).
337 ProMedica Health Sys., Inc., 749 F.3d at 567.
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be rationales for clustering noncompeting products in the same market.338 Whether “online
superstores” represent an appropriately defined market for any of these reasons will likely turn on
the factual evidence that the FTC can ultimately adduce.
By alleging separate markets for “online superstores” and “online marketplace services,” the
FTC’s complaint also raises questions regarding the impact of the Supreme Court’s 2018 decision
in Ohio v. American Express (Amex).339 In Amex, the Court held that two-sided transaction
platforms like credit-card networks represent a single market, meaning a price increase on one
side of such a market (there, an increase in merchant fees) cannot by itself demonstrate an
anticompetitive exercise of market power.340 Instead, the Court concluded that the plaintiffs in
Amex needed to show anticompetitive effects on the credit-card market “as a whole”—for
example, that the defendant’s conduct increased the price or reduced the number of credit-card
transactions.341
Amex’s implications for the FTC’s case against Amazon are unclear. In a 2018 article, the current
FTC Chair argued that the Supreme Court’s reasoning in Amex appeared to apply to Amazon’s
marketplace.342 While the article did not elaborate on that assessment, there are similarities
between Amazon’s platform and credit-card networks. In Amex, the Court justified its
single-market conclusion on the ground that credit-card networks cannot make sales “unless both
sides of the platform [i.e., merchants and cardholders] simultaneously agree to use their
services.”343 As a result, the Court reasoned, credit-card networks cannot set prices for one side of
the market without considering the impact of those prices on the other side of the market.344
Similar dynamics may be at work in Amazon’s case. By allegedly charging monopoly prices to
sellers, Amazon may risk losing participants on that side of its platform, which would decrease
the value of its marketplace to consumers. If consumers shop elsewhere as a result, that would
further diminish the value of Amazon’s platform to sellers, setting off a negative feedback loop.345
The court may thus rely on Amex to reject the FTC’s effort to define separate markets for “online
superstores” and “online marketplace services.”
Some commentators, however, have highlighted possible distinctions between Amazon’s
marketplace and credit-card networks. While credit-card networks do little besides facilitate
transactions, for example, Amazon offers sellers a range of additional services.346 Whether these
types of distinctions will allow the FTC to sidestep Amex’s single-market rule for two-sided
transaction platforms remains to be seen.

338 Hovenkamp, Digital Cluster Markets, supra note 333, at 255-56, 262-71.
339 138 S. Ct. 2274 (2018).
340 Id. at 2287.
341 Id.
342 Lina Khan, The Supreme Court Just Quietly Gutted Antitrust Law, VOX (July 3, 2018), https://www.vox.com/the-
big-idea/2018/7/3/17530320/antitrust-american-express-amazon-uber-tech-monopoly-monopsony.
343 Amex, 138 S. Ct. at 2286.
344 Id.
345 Id. at 2281 (describing these dynamics and the interconnected pricing that allegedly results from them).
346 Dan Papscun, Amazon Antitrust Case Must Clear Amex Bar Set by Supreme Court, BLOOMBERG LAW (Sept. 29,
2023), https://news.bloomberglaw.com/antitrust/amazon-antitrust-case-must-clear-amex-bar-set-by-supreme-court;
Tim Wu, The American Express Opinion, Tech Platforms & the Rule of Reason, 7 J. ANTITRUST ENFORCEMENT 117
(2018).
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Allegations of Anticompetitive Conduct
Anti-Discounting Measures
Several lawsuits have alleged that Amazon has implemented measures to punish sellers on its
marketplace for offering lower prices in other transaction venues. The FTC’s lawsuit contends
that Amazon disqualifies sellers from appearing in its Buy Box—which features a product’s price
and the “Add to Cart” button, among other information—if Amazon discovers sellers offering
their products for a lower price in another online store.347 The complaint further alleges that
Amazon has entered into contracts with certain important sellers that prohibit the sellers from
discounting their products in other online stores.348 The FTC claims that these anti-discounting
measures prevent rival online marketplaces from offering products at lower prices and deprives
those rivals of necessary scale.349
The D.C. AG lawsuit and the consumer class action discussed above made similar allegations.350
As discussed, the Superior Court of the District of Columbia has dismissed the D.C. AG’s
complaint,351 and the D.C. AG has appealed that decision.352 The district court in the consumer
lawsuit, by contrast, denied Amazon’s motion to dismiss, concluding that the plaintiffs had
plausibly alleged that Amazon’s conduct caused anticompetitive harm.353
Amazon has rejected the allegation that the relevant policies are anticompetitive, arguing that
they reflect a decision to highlight products that are competitively priced.354
Tying of Amazon Prime and Amazon’s Fulfillment Service
The FTC’s lawsuit also alleges that Amazon maintains its monopolies by coercing sellers to use
its fulfillment services (i.e., storing, packaging, and preparing products for shipment).355
Specifically, the FTC contends that Amazon effectively requires sellers to use its fulfillment
services as a condition of participating in Amazon Prime—a subscription program that offers
customers fast shipping of eligible products, among other benefits.356 Prime eligibility boosts a
seller’s chances of winning the Buy Box, the FTC alleges, while sellers that forgo Prime
eligibility “effectively disappear from Amazon’s storefront.”357

347 Complaint ¶ 269, FTC v. Amazon.com, Inc., No. 2:23-cv-01495 (W.D. Wash. Sept. 26, 2023).
348 Id.
349 Id. ¶¶ 305-10, 324.
350 Frame-Wilson v. Amazon.com, Inc., 591 F. Supp. 3d 975, 981-82 (2022); First Amended Complaint ¶¶ 5-10,
District of Columbia v. Amazon.com, Inc., No. 2021-CA-001775 (D.C. Super. Ct. Sept. 10, 2021).
351 Order at 8-9, 15-16, District of Columbia v. Amazon.com, Inc., No. 2021-CA-001775 (D.C. Super. Ct. Aug. 1,
2022).
352 Notice of Appeal, District of Columbia v. Amazon.com, Inc., No. 2021-CA-001775 (D.C. Super. Ct. Aug. 25,
2022).
353 Frame-Wilson, 591 F. Supp. 3d at 991-92.
354 David Zapolsky, The FTC’s Lawsuit Against Amazon Would Lead to Higher Prices and Slower Deliveries for
Consumers—And Hurt Businesses, AMAZON (Sept. 26, 2023), https://www.aboutamazon.com/news/company-
news/amazon-ftc-antitrust-lawsuit-full-response.
355 Complaint ¶ 351, FTC v. Amazon.com, Inc., No. 2:23-cv-01495 (W.D. Wash. Sept. 26, 2023).
356 Id. ¶ 353. In 2022, the European Commission accepted certain commitments from Amazon to resolve similar
concerns. See Amazon EC Commitments, supra note 328. Among other things, Amazon agreed to treat all sellers
equally in managing its Buy Box and to allow third-party sellers that participate in Prime to freely choose their logistics
and delivery services. Id.
357 Complaint ¶ 352, FTC v. Amazon.com, Inc., No. 2:23-cv-01495 (W.D. Wash. Sept. 26, 2023).
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The FTC argues that Amazon’s tying of Prime to its fulfillment services stifles the growth of
other online marketplaces in two ways. First, by allegedly tying Prime to its fulfillment services,
Amazon effectively requires sellers that want to use both Amazon’s marketplace and other online
marketplaces to use two separate fulfillment providers.358 This duplication, the FTC contends,
creates extra costs that could be avoided by consolidating inventory with one fulfillment provider,
which deters sellers from using other online marketplaces.359 Second, Amazon’s conduct
allegedly prevents independent fulfillment providers from gaining necessary scale, which
likewise increases the costs to sellers of utilizing multiple online marketplaces.360
In response, Amazon has said that it allows sellers that participate in Prime to use other
fulfillment providers as long as those providers “are able to meet . . . Prime customers’ high
expectations for fast, reliable delivery.”361
Use of Third-Party Seller Data
Amazon’s dual role as both a marketplace operator and a seller on its own marketplace has also
attracted scrutiny. Critics have contended that this integration generates conflicts of interest,
which have led Amazon to leverage control of its marketplace to advantage its own products and
services in various ways.362
Some of these allegations involve Amazon’s use of data. The HJC Report and European
regulators have accused Amazon of using data generated by third-party sellers on its marketplace
to identify and imitate popular products for its private-label business.363
During congressional testimony in July 2020, Amazon’s founder and former chief executive said
that the company has a policy against using seller-specific data to aid its private-label business.364
He indicated, however, that he could not guarantee that this policy had never been violated.365
Amazon reportedly does not have a policy against using aggregated seller data to assist its retail
business.366
Commentators have disputed the competitive effects of a platform’s use of user data to enter new
markets. Some have argued that Amazon’s entry into new markets forces other sellers to lower

358 Id. ¶ 366.
359 Id.
360 Id.
361 Zapolsky, supra note 354.
362 HJC REPORT, supra note 11, at 16; see also Lina M. Khan, The Separation of Platforms and Commerce, 119
COLUM. L. REV. 973, 985-94 (2019) [hereinafter “Khan, Platforms and Commerce”].
363 HJC REPORT, supra note 11, at 274-82; Press Release, Euro. Comm’n, Antitrust: Commission Sends Statement of
Objections to Amazon for the Use of Non-Public Independent Seller Data and Opens Second Investigation into its E-
Commerce Business Practices (Nov. 10, 2020), https://ec.europa.eu/commission/presscorner/detail/en/ip_20_2077.
364 HJC REPORT, supra note 11, at 277-78.
365 Id.
366 Id. at 278. The European Commission has investigated similar issues. In 2020, the Commission preliminarily
concluded that Amazon had relied on aggregated data generated by third-party sellers to support its own retail
offerings. See Amazon EC Commitments, supra note 328. In December 2022, the Commission accepted Amazon’s
commitment not to use non-public data derived from third-party sellers to assist its private-label business. See id.
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their prices—an outcome that antitrust traditionally encourages.367 Others contend that the alleged
copying may have longer-term anticompetitive effects by chilling incentives to innovate.368
Self-Preferencing
Amazon’s dual role as a marketplace operator and private-label seller has led to a range of other
concerns about self-preferencing. For example, a 2016 ProPublica investigation concluded that
Amazon designed the ranking algorithm for its marketplace to favor its own offerings and
products offered by sellers that use its fulfillment services.369 The HJC Report alleged that
Amazon has engaged in other forms of self-preferencing, such as refusing to allow certain
competitors to advertise on Amazon’s platform.370
Predatory Pricing
Amazon has also been accused of engaging in predatory pricing at various points in its history.371
These allegations have been directed against several aspects of Amazon’s business, including its
sale of e-books;372 its sale of diapers and ultimate acquisition of the parent company of
Diapers.com;373 and Amazon Prime.374
In previous academic work, the current FTC Chair has argued that Amazon exemplifies the
rationality of predatory pricing in markets characterized by strong network effects and extreme
scale economies, contrary to the assumptions that underpin current doctrine.375
Other commentators have challenged these allegations.376 In response to the claims involving
Diapers.com, some have noted that Amazon has not been accused of occupying a monopolistic
share of the market for online diaper sales or diaper sales generally.377 Others have argued that the
HJC Report failed to produce sufficient evidence to conclude that Amazon prices Prime
memberships below cost.378 Commentators have also questioned whether Amazon’s critics are

367 See, e.g., Francis, supra note 63, at 832; Herbert Hovenkamp, Antitrust and Platform Monopoly, 130 YALE L.J.
1952, 2015 (2021) [hereinafter “Hovenkamp, Platform Monopoly”].
368 ARIEL EZRACHI & MAURICE E. STUCKE, HOW BIG-TECH BARONS SMASH INNOVATION—AND HOW TO STRIKE BACK
54-57 (2022). These issues are discussed in greater detail in infra “Use of Nonpublic User Data.”
369 Julia Angwin & Surya Mattu, Amazon Says It Puts Customers First. But Its Pricing Algorithm Doesn’t, PROPUBLICA
(Sept. 20, 2016), https://www.propublica.org/article/amazon-says-it-puts-customers-first-but-its-pricing-algorithm-
doesnt.
370 HJC REPORT, supra note 11, at 283-86.
371 See, e.g., Shaoul Sussman, Prime Predator: Amazon and the Rationale of Below Average Variable Cost Pricing
Strategies Among Negative-Cash Flow Firms, 7 J. ANTITRUST ENFORCEMENT 203 (2019).
372 Khan, Amazon’s Antitrust Paradox, supra note 79, at 756-68.
373 Id. at 768-74; HJC REPORT, supra note 11, at 297-99.
374 HJC REPORT, supra note 11, at 299-300.
375 Khan, Amazon’s Antitrust Paradox, supra note 79, at 753, 786, 791-92.
376 Kristian Stout & Alec Stapp, Is Amazon Guilty of Predatory Pricing?, TRUTH ON THE MARKET (May 7, 2019),
https://truthonthemarket.com/2019/05/07/is-amazon-guilty-of-predatory-pricing/; Jeffrey Eisenach, Who Should
Antitrust Protect? The Case of Diapers.com, AM. ENTER. INST. (Nov. 5, 2018), https://www.aei.org/technology-and-
innovation/who-should-antitrust-protect-the-case-of-diapers-com/.
377 Eisenach, supra note 376.
378 Carl Shapiro, Regulating Big Tech: Factual Foundations and Policy Goals, NETWORK L. REV. (forthcoming Fall
2023), https://www.networklawreview.org/shapiro-big-tech/.
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relying on a coherent concept of predation, contending that some of the relevant literature appears
to reject the idea that raising prices at some point is a necessary part of a predatory strategy.379
Apple
Apple is the most valuable company in the world.380 The firm designs, manufactures, and sells
iPhone smartphones, Mac personal computers, iPad tablets, and several wearables and
accessories, in addition to offering a range of related services.381 The discussion below focuses on
issues related to the company’s mobile operating system and App Store.
Allegations of Market Power
As discussed, Apple’s iOS and Google’s Android are the two dominant operating systems for
mobile devices in the United States and globally.382 More than half of the mobile devices in the
United States run a version or derivation of iOS.383 Apple’s App Store is the only method by
which software developers can distribute apps on iOS devices; Apple does not allow iOS users to
download other app stores or sideload apps.384 Like Google, Apple requires developers to use its
IAP processor as a condition of accessing its App Store and has charged 30% commissions for
that service.385
In 2020, Epic Games—the developer of the video game Fortnite—challenged these restrictions
under Sections 1 and 2 of the Sherman Act. Epic alleged single-brand aftermarkets for iOS app
distribution and iOS in-app payment processing in which Apple possessed monopoly power.386
Apple denied Epic’s allegations, arguing that the relevant market consists of all video game
transactions, including transactions involving gaming consoles, personal computers, and
streaming services.387
In September 2021, a federal district court arrived at a conclusion that fell between the two
parties’ positions. Instead of a single-brand aftermarket for iOS app distribution or a market for
video-game distribution generally, the court held that Apple competes in a market for digital
mobile gaming transactions, which includes transactions on iOS and Android mobile devices.388

379 Herbert Hovenkamp, Whatever Did Happen to the Antitrust Movement?, 94 NOTRE DAME L. REV. 583, 588-89
(2019).
380 Largest Companies by Market Cap, COMPANIESMARKETCAP (last visited Nov. 6, 2023),
https://companiesmarketcap.com/.
381 Apple Inc., Annual Report (Form 10-K) at 1-2 (Oct. 28, 2022).
382 HJC REPORT, supra note 11, at 100-02.
383 Id. at 334.
384 Id. at 335.
385 Epic Games, Inc. v. Apple, Inc., 67 F.4th 946, 967 (9th Cir. 2023).
386 Id. at 970. An aftermarket is a market in which demand for a good or service (e.g., an iOS app) depends on an
earlier purchase of a durable good (e.g., an iPhone). The Supreme Court has held that, in some cases, single-brand
aftermarkets can constitute relevant antitrust markets. Eastman Kodak Co. v. Image Tech. Servs., Inc., 504 U.S. 451
(1992). In acknowledging the possibility of relevant aftermarkets, the Court reasoned that, in certain instances,
asymmetric information and high switching costs can result in consumers being “locked in” to the use of aftermarket
products, preventing foremarket competition from disciplining a firm’s aftermarket conduct. Id. at 477-78. Lower
courts have generally applied this doctrine narrowly. See David A.J. Goldfine & Kenneth M. Vorrasi, The Fall of the
Kodak Aftermarket Doctrine: Dying a Slow Death in the Lower Courts, 72 ANTITRUST L.J. 209 (2004).
387 Id.
388 Epic Games, Inc. v. Apple Inc., 559 F. Supp. 3d 898, 921 (N.D. Cal. 2021).
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The district court rejected Epic’s narrower proposed aftermarkets for several reasons, including
Epic’s failure to establish consumer unawareness of Apple’s restrictions or produce evidence of
the magnitude of the relevant switching costs.389
The court ultimately concluded that Apple possesses market power—but not monopoly power—
in the market for digital mobile gaming transactions.390
Epic appealed that decision. In April 2023, the Ninth Circuit took issue with some aspects of the
district court’s market-definition analysis, but affirmed the court’s rejection of Epic’s proposed
aftermarkets and the holding that Apple does not possess monopoly power.391
Allegations of Anticompetitive Conduct
Mobile App Distribution and IAP Processing
As discussed, the Epic Games lawsuit challenged Apple’s requirement that iOS app developers
distribute their apps through Apple’s App Store and use Apple’s payment processor for in-app
purchases.392 The lawsuit also targeted anti-steering provisions in Apple’s developer agreements,
which prohibit developers from using certain communications methods—such as in-app links—to
inform users about out-of-app payment options.393
In Epic Games, the district court concluded that the first two restrictions did not violate the
Sherman Act, but that Apple’s anti-steering provisions violated California competition law.394 In
rejecting Epic’s federal antitrust claims, the district court concluded that Apple had proffered
valid procompetitive justifications for its App Store and payment-processor requirements based
on their promotion of security, privacy, and the monetization of intellectual property.395 The
district court further concluded that Epic had not shown that those procompetitive benefits could
be achieved through less restrictive means.396
On appeal, the Ninth Circuit affirmed the district court’s decision.397 In affirming the district
court’s rejection of Epic’s Section 1 tying claim, the appellate court concluded that the modified
per se rule against tying does not apply to ties involving platform software products, following
the D.C. Circuit’s reasoning in Microsoft.398 While the Ninth Circuit disagreed with some aspects
of the district court’s rule-of-reason analysis, it affirmed the finding that Epic failed to show that
Apple could achieve the relevant procompetitive benefits through less restrictive means.399

389 Id. at 1021-26.
390 Id. at 922.
391 Epic Games, Inc. v. Apple, Inc., 67 F.4th 946, 980-81, 998-99 (9th Cir. 2023).
392 Id. at 968.
393 Id.
394 Epic Games, Inc. v. Apple Inc., 559 F. Supp. 3d 898, 1033-57 (N.D. Cal. 2021).
395 Id. at 1038-40.
396 Id. at 1040-41.
397 Epic Games, 67 F.4th at 981-99.
398 Id. at 997. The district court had denied Epic’s tying claim on the ground that app distribution and in-app payment
processing are not separate products—a conclusion that the Ninth Circuit rejected. Id. at 996.
399 Id. at 993-94.
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Self-Preferencing
The HJC Report alleged that Apple has taken a variety of steps to preference its own apps and
harm rival app developers.400 Among other things, the report accused Apple of injuring
competition by preinstalling its own apps on iPhones;401 denying third-party apps access to
certain APIs and device functionalities that are available to its own apps;402 favoring its own apps
in search results on its App Store;403 and removing rival apps from the App Store.404
Apple has denied giving preferential treatment to its own apps in search rankings.405 The
company has claimed that it has removed specific apps from its App Store based on violations of
its privacy policies.406
Use of Competitively Sensitive Information
Like Amazon, Apple has faced allegations that it uses its access to data generated by dependent
businesses to identify and imitate popular offerings.407 In particular, software developers have
accused Apple of using competitively sensitive information about popular apps to build
competing apps and integrate certain functionalities into iOS.408
Apple has responded to such allegations by stating that it does not violate other companies’
intellectual property rights.409
Big Tech Mergers and Acquisitions
Some of the allegations discussed above involve Big Tech mergers and acquisitions. As noted, the
FTC is currently challenging Facebook’s acquisitions of Instagram and WhatsApp,410 while
Google’s acquisition of DoubleClick is a key part of the DOJ’s monopolization lawsuit targeting
the company’s ad-tech practices.411
Some policymakers have expressed broader concerns about Big Tech mergers.412 The companies
have been active dealmakers: between 2000 and 2019, the four firms engaged in hundreds of

400 HJC REPORT, supra note 11, at 352.
401 Id.
402 Id. at 354. In May 2022, the European Commission preliminarily determined that Apple had violated European
Union competition law by limiting rival mobile wallet developers from accessing certain technology that Apple makes
available to its own wallet, Apple Pay. See Press Release, Euro. Comm’n, Antitrust: Commission Sends Statement of
Objections to Apple Over Practices Regarding Apple Pay (May 2, 2022), https://ec.europa.eu/commission/presscorner/
detail/en/ip_22_2764.
403 HJC REPORT, supra note 11, at 359-61.
404 Id. at 364-67.
405 Id. at 361.
406 Id. at 366.
407 Id. at 361-64.
408 Id. at 362.
409 Id. at 363.
410 FTC v. Facebook, Inc., 581 F. Supp. 3d 34 (D.D.C. 2022).
411 Complaint, United States v. Google LLC, No. 1:23-cv-00108 (E.D. Va. Jan. 24, 2023). For a more detailed
discussion of mergers and acquisitions in tech markets, see CRS Report R46739, Mergers and Acquisitions in Digital
Markets, by Clare Y. Cho.
412 HJC REPORT, supra note 11, at 387; SUBCOMM. ON ANTITRUST, COM., AND ADMIN. L. OF THE H. COMM. ON THE
JUDICIARY, 116TH CONG., THE THIRD WAY: ANTITRUST ENFORCEMENT IN BIG TECH 9 (2020) (written by Ken Buck, et
(continued...)
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mergers and acquisitions.413 Many of the transactions fell below the numerical thresholds that
trigger pre-merger review by the antitrust agencies.414
These deals have prompted some commentators to worry that the Big Tech firms are cementing
their dominant positions by acquiring promising potential competitors.415 Transactions involving
“nascent” competitors have been a particular point of concern.416 While the concept of a nascent
competitor has been defined in different ways, it generally refers to an innovative firm that
represents a serious yet uncertain future threat to an incumbent.417
These issues are discussed in greater detail in “Mergers & Acquisitions” infra.418
Antitrust Reform and Big Tech: General Issues
The issues discussed above have prompted calls for reform. Some proposals would supplement
the antitrust laws with sectoral competition regulations directed at large technology platforms.419

al. in response to majority report), https://buck.house.gov/sites/evo-subsites/buck-
evo.house.gov/files/wysiwyg_uploaded/Buck%20Report.pdf.
413 Diana L. Moss, The Record of Weak U.S. Merger Enforcement in Big Tech, AM. ANTITRUST INST. 6 (July 8, 2019),
https://www.antitrustinstitute.org/wp-content/uploads/2019/07/Merger-Enforcement_Big-Tech_7.8.19.pdf.
414 FED. TRADE COMM’N, NON-HSR REPORTED ACQUISITIONS BY SELECT TECHNOLOGY PLATFORMS, 2010-2019: AN FTC
STUDY (Sept. 2021), https://www.ftc.gov/system/files/documents/reports/non-hsr-reported-acquisitions-select-
technology-platforms-2010-2019-ftc-study/p201201technologyplatformstudy2021.pdf [hereinafter “FTC Non-
Reportable Acquisitions Study”].
415 Steven C. Salop, Dominant Digital Platforms: Is Antitrust Up to the Task?, 130 YALE L.J. F. 563, 578-79 (2021);
Mark Glick, et al., Big Tech’s Buying Spree and the Failed Ideology of Competition Law, 72 HASTINGS L.J. 465,
468-75 (2021); JONATHAN B. BAKER, THE ANTITRUST PARADIGM: RESTORING A COMPETITIVE ECONOMY 160-61 (2019);
HJC REPORT, supra note 11, at 387; Tim Wu & Stuart A. Thompson, The Roots of Big Tech Run Disturbingly Deep,
N.Y. TIMES (June 7, 2019), https://www.nytimes.com/interactive/2019/06/07/opinion/google-facebook-mergers-
acquisitions-antitrust.html; STIGLER CTR. FOR THE STUDY OF THE ECON. AND THE STATE, STIGLER COMM. ON DIGITAL
PLATFORMS: FINAL REPORT 71-72, 75 n.152 (2019), https://www.chicagobooth.edu/-
/media/research/stigler/pdfs/digital-platforms---committee-report---stigler-center.pdf [hereinafter “STIGLER REPORT”];
HM TREASURY, UNLOCKING DIGITAL COMPETITION, REPORT OF THE DIGITAL COMPETITION EXPERT PANEL 40 (2019),
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/785547/unlocking_di
gital_competition_furman_review_web.pdf [hereinafter “UK DIGITAL COMPETITION REPORT”].
416 A. Douglas Melamed, Mergers Involving Nascent Competition, Stanford L. and Econ. Olin Working Paper No. 566
(Jan. 17, 2022), https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4009229; John M. Yun, Are We Dropping the
Crystal Ball? Understanding Nascent & Potential Competition in Antitrust, 104 MARQ. L. REV. 613 (2021); C. Scott
Hemphill & Tim Wu, Nascent Competitors, 168 U. PA. L. REV. 1879 (2020); OECD, START-UPS, KILLER ACQUISITIONS
AND MERGER CONTROL 21-36 (2020), https://www.oecd.org/daf/competition/start-ups-killer-acquisitions-and-merger-
control-2020.pdf [hereinafter “OECD STARTUP ACQUISITION REPORT”].
417 Yun, supra note 416, at 626-29; Hemphill & Wu, supra note 416, at 1883.
418 The FTC was unsuccessful in its first effort to block a Big Tech merger using a potential-competition theory. In
January 2023, a federal district court denied the FTC’s motion for an injunction against Meta’s proposed acquisition of
Within Unlimited—the developer of a virtual-reality (VR) fitness app. Order Denying Plaintiff’s Motion for
Preliminary Injunction, FTC v. Meta Platforms Inc., No. 5:22-cv-04325 (N.D. Cal. Jan. 31, 2023). In that case, Meta
was the putative potential entrant. The FTC alleged that, absent the acquisition, Meta would have organically entered
the market for VR fitness apps. Id. at 39. The Commission also offered a perceived-potential-competition argument,
contending that the prospect of Meta’s entry exerted competitive pressures on that market. Id. at 60. The district court
rejected both theories, concluding that the FTC failed to establish a “reasonable probability” of entry absent the
acquisition or that Meta was perceived as a potential competitor. Id. at 59, 62.
419 See infra “Ex Ante Conduct Rules,” “Structural Separation and Line-of-Business Restrictions,” “Mergers &
Acquisitions” & “Interoperability & Data Portability.”
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Others would work within the existing antitrust framework by adjusting burdens of proof and
changing certain doctrinal rules.420
While the relevant options are varied, they all implicate the threshold question of whether tech
platform markets have unique features that warrant special treatment under competition law. The
proposals that would supplement antitrust with a new regulatory regime raise additional questions
regarding scope and administration.
This section of the report discusses these general issues in the debate over antitrust reform
directed at Big Tech firms.
Are Tech Platforms Special?
As discussed, outside of a narrow set of per se offenses, antitrust is a fact-specific enterprise.
Generally, courts employ a case-by-case approach to evaluate claims of anticompetitive
behavior.421 Because liability typically depends on case-specific facts rather than the application
of bright-line rules, antitrust investigations and litigation are often time-consuming and
expensive.422 The open-ended nature of the relevant legal standards can also make it difficult to
predict whether certain conduct violates the law, which may undermine enforcement by allowing
large firms to profit from anticompetitive strategies and treat potential lawsuits as a cost of doing
business.423
Advocates of reform have argued that these features of antitrust adjudication make it ill-suited to
deal with tech platform markets characterized by a unique confluence of structural characteristics,
such as strong network effects, economies of scale, economies of scope derived from user data,
and consumer tendencies to single-home.424
According to some, these characteristics cause certain platform markets to tip in favor of a single
dominant firm.425 After an initial period of competition, one company may gain an edge that
becomes self-reinforcing. For example, a platform with a large user base and associated data
advantages may be the most attractive to new users, generating a positive feedback loop that
allows it to grow even larger and thereby become even more attractive.426 Prospective entrants
may then face difficulties achieving the scale necessary to compete with the dominant
incumbent.427

420 See infra “Changes to General Antitrust.”
421 William P. Rogerson & Howard Shelanski, Antitrust Enforcement, Regulation, and Digital Platforms, 168 U. PA. L.
REV. 1911, 1917-18 (2020).
422 Rohit Chopra & Lina M. Khan, The Case for “Unfair Methods of Competition” Rulemaking, 87 U. CHI. L. REV.
357, 360-62 (2020); Daniel A. Crane, Rules Versus Standards in Antitrust Adjudication, 64 WASH. & LEE L. REV. 49,
83 (2007).
423 Chopra & Khan, supra note 422, at 360-61.
424 STIGLER REPORT, supra note 415, at 7-8, 99; UK DIGITAL COMPETITION REPORT, supra note 415, at 5. While many
markets have one or more of these features, some commentators have argued that their combination and strength in
digital-platform markets raise unique challenges for antitrust enforcers. See, e.g., Michael Kades & Fiona Scott Morton,
Interoperability as a Competition Remedy for Digital Networks, WASH. CTR. FOR EQUITABLE GROWTH 7 n.14 (Sept. 23,
2020), https://equitablegrowth.org/working-papers/interoperability-as-a-competition-remedy-for-digital-networks/.
425 EZRACHI & STUCKE, supra note 368, at 10-11; STIGLER REPORT, supra note 415, at 34-36; UK DIGITAL COMPETITION
REPORT, supra note 415, at 4.
426 Michael L. Katz & Carl Shapiro, Systems Competition and Network Effects, 8 J. ECON. PERSP. 93, 105-06 (1994).
427 Joseph Farrell & Paul Klemperer, Coordination and Lock-In: Competition with Switching Costs and Network
Effects, in 3 HANDBOOK OF INDUSTRIAL ORGANIZATION 1970, 1974 (Mark Armstrong & Robert H. Porter eds., 2007).
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Big Tech firms may also derive benefits from their roles as gatekeepers for key digital
ecosystems, like mobile operating systems, app stores, online marketplaces, and social
networks.428 By controlling access to these ecosystems and setting the rules within them, tech
platforms can allegedly preserve their dominant positions and leverage those positions to obtain
advantages in related markets.429
Some analysts contend that antitrust adjudication is too slow to adequately police markets
characterized by these winner-take-all dynamics.430 By the time a market has tipped, they suggest,
remedies for anticompetitive conduct may be unable to restore meaningful competition.431
Occasionally, this line of argument involves the claim that a particular digital platform is a natural
monopoly, meaning its cost structure is such that market demand can be served most efficiently
by a single firm.432 In such industries—public utilities are prominent examples—competition is
unable to discipline market participants, which has traditionally led policymakers to favor direct
regulations of price, entry, and quality of service.433
Other commentators have rejected the claim that antitrust is unable to grapple with competition
issues involving large digital platforms. Some dispute that Big Tech markets have all decisively
tipped in favor of a single firm.434 Rather, they contend that the tech giants compete in diverse
markets characterized by different competitive dynamics.435 While some of those markets may be
susceptible to tipping, others arguably retain a competitive fringe or exhibit competition among
rivals of comparable size.436 This variety is said to emerge from several characteristics that
distinguish many online platforms from traditional natural monopolies, including product
differentiation, multi-homing by consumers, and low switching costs.437 Defenders of the current
antitrust regime have thus emphasized the heterogeneity of platform markets, which they contend

428 EZRACHI & STUCKE, supra note 368, at 45-50; Marco Cappai & Giuseppe Colangelo, Taming Digital Gatekeepers:
The More Regulatory Approach to Antitrust Law, Stanford-Vienna TTLF Working Paper 9 (Stanford-Vienna TTLF,
Working Paper No. 55, 2020).
429 OECD, EX ANTE REGULATION AND COMPETITION IN DIGITAL MARKETS 10 (2021),
https://www.oecd.org/daf/competition/ex-ante-regulation-and-competition-in-digital-markets-2021.pdf.
430 Giorgio Monti, The Digital Markets Act—Institutional Design and Suggestions for Improvement 1 (Tilburg L. &
Econ. Ctr., Discussion Paper No. 2021-04, 2021); STIGLER REPORT, supra note 415, at 99; UK DIGITAL COMPETITION
REPORT, supra note 415, at 6.
431 EZRACHI & STUCKE, supra note 368, at 173-75; Monti, supra note 430, at 1; STIGLER REPORT, supra note 415, at 99;
UK DIGITAL COMPETITION REPORT, supra note 415, at 6.
432 FRANCESCO DUCCI, NATURAL MONOPOLIES IN DIGITAL PLATFORM MARKETS 74 (2020) (concluding that Google
Search is a natural monopoly); STIGLER REPORT, supra note 415, at 99 (arguing that certain structural features “push
social media platforms towards natural monopoly”); see also UK DIGITAL COMPETITION REPORT, supra note 415, at 54
(rejecting the contention that major digital platforms are natural monopolies, while acknowledging that “they share
some important characteristics with natural monopolies”).
433 Richard A. Posner, Natural Monopoly and Its Regulation, 21 STAN. L. REV. 548, 548 (1968).
434 E.g., Hovenkamp, Platform Monopoly, supra note 367, at 1978; see also NICOLAS PETIT, BIG TECH AND THE DIGITAL
ECONOMY: THE MOLIGOPOLY SCENARIO 153-71, 257 (2020) (arguing that Big Tech firms face meaningful competitive
pressures even when operating in tipped markets); How Tech’s Defiance of Economic Gravity Came to an Abrupt End,
THE ECONOMIST (Dec. 24, 2022), https://www.economist.com/business/2022/12/24/how-techs-defiance-of-economic-
gravity-came-to-an-abrupt-end (arguing that some Big Tech firms face “fierce” competition from one another and from
new rivals); Ryan Bourne & Rachel Chiu, A Monopoly of What? Big Tech in Today’s Context, CATO INST. (Nov. 3,
2022), https://www.cato.org/commentary/monopoly-what-big-tech-todays-context (similar).
435 PETIT, supra note 434, at 257-58; Joshua D. Wright & John M. Yun, Platforms in the Spotlight at FTC Hearings,
Geo. Mason L. & Econ. Research Paper No. 18-44 at 3 (Nov. 2018),
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3280532.
436 Hovenkamp, Platform Monopoly, supra note 367, at 1978.
437 DUCCI, supra note 432, at 42-43.
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militates against categorical treatment of Big Tech firms and in favor of the existing fact-specific
approach.438
Some observers have gone further in their rejection of sectoral regulation, arguing that many tech
markets have features that support a cautious approach to intervention under the existing antitrust
laws. This perspective emphasizes the distinction between static price competition and the
dynamic rivalry prevalent in tech markets, which involves efforts to develop new products,
services, and business models.
Commentators have argued that dynamic competition has non-interventionist implications for
several areas of antitrust doctrine.
First, in dynamic industries, traditional market definition may overstate the market power of
leading firms.439 In particular, static market shares may exaggerate a platform’s market power by
failing to account for the threat of displacement by differentiated or innovative rivals.440
Examples of this type of displacement include Facebook supplanting MySpace as the leading
social network and Google unseating Yahoo! and AltaVista to become the dominant search
engine. In both cases, the ousted incumbents were widely perceived as invulnerable—an
assumption that proved incorrect.441 Some observers have highlighted these episodes in arguing
that Big Tech platforms face constant competitive pressure despite occupying large static market
shares.442
Second, technological innovation often involves combining products or features that were
previously available only as separate offerings. Although this type of product integration often
benefits consumers, it is also potentially vulnerable to antitrust challenge under tying law.443 To
avoid chilling innovation, some courts and commentators have endorsed exceptions to the
modified per se rule against tying for platform software products.444 Other observers have gone
further and advocated a rule of per se legality for the introduction of new products.445

438 ABA ANTITRUST L. SECTION, COMMON ISSUES RELATING TO THE DIGITAL ECONOMY AND COMPETITION, REPORT OF
THE INTERNATIONAL DEVELOPMENTS AND COMMENTS TASK FORCE ON POSITIONS EXPRESSED BY THE ABA ANTITRUST
LAW SECTION BETWEEN 2017 AND 2019, at 5 (2020) [hereinafter “ABA DIGITAL ECONOMY REPORT”]; Group of Seven
(G7), Common Understanding of G7 Competition Authorities on “Competition and the Digital Economy” (June 5,
2019), https://www.autoritedelaconcurrence.fr/sites/default/files/2019-11/g7_common_understanding.pdf.
439 Jerry Ellig & Daniel Lin, A Taxonomy of Dynamic Competition Theories, in DYNAMIC COMPETITION AND PUBLIC
POLICY: TECHNOLOGY, INNOVATION, AND ANTITRUST ISSUES 16, 24, 30 (Jerry Ellig ed. 2001).
440 J. Gregory Sidak & David J. Teece, Dynamic Competition in Antitrust Law, J. COMPETITION L. & ECON. 581, 614-15
(2009); Richard Schmalensee, Antitrust Issues in Schumpeterian Industries, 90 AM. ECON. REV. 192, 193 (2000).
441 Victor Keegan, Will MySpace Ever Lose Its Monopoly?, THE GUARDIAN (Feb. 8, 2007),
https://www.theguardian.com/technology/2007/feb/08/business.comment; Randall E. Stross, How Yahoo! Won the
Search Wars, FORTUNE (Mar. 2, 1998),
https://money.cnn.com/magazines/fortune/fortune_archive/1998/03/02/238576/.
442 See, e.g., David S. Evans, Why the Dynamics of Competition for Online Platforms Leads to Sleepless Nights, But
Not Sleepy Monopolies (Aug. 23, 2017), https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3009438; D. Daniel
Sokol & Jingyuan (Mary) Ma, Understanding Online Markets and Antitrust Analysis, 15 NW. J. TECH. & INTELL. PROP.
43, 48 (2017).
443 See generally John M. Newman, Anticompetitive Product Design in the New Economy, 39 FLA. ST. U. L. REV. 681
(2012).
444 E.g., Epic Games, Inc. v. Apple, Inc., 67 F.4th 946, 997 (9th Cir. 2023); United States v. Microsoft, 253 F.3d 34,
89-90 (D.C. Cir. 2001) (per curiam); David S. Evans & Richard Schmalensee, Some Economic Aspects of Antitrust
Analysis in Dynamically Competitive Industries, 2 INNOVATION POLICY AND THE ECON. 1, 30-33 (2002).
445 Geoffrey A. Manne & Joshua D. Wright, Innovation and the Limits of Antitrust, 6 J. COMPETITION L. & ECON. 153
(2010).
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Third, dynamic competition may raise complications in assessing claims of price predation. The
alleged difficulty arises from the fact that technology firms often offer low or zero prices to
encourage widespread adoption of new products. In winner-take-all markets with network effects,
all firms may charge low prices—which may entail short-term losses—with an eye toward
recoupment once they surpass rivals.446 Some commentators have questioned the appropriateness
of traditional cost and recoupment tests for predation claims in markets characterized by this type
of competition.447
Others have argued that the two-sided nature of certain platform markets raises additional
difficulties for predation analysis. The potential trouble involves indirect network effects,
whereby a platform becomes more valuable to users on one side (e.g., advertisers, merchants) as
it gains more users on the other side (e.g., users of a search engine, e-commerce customers).448 In
such markets, evaluating a firm’s pricing on only one side of a platform may be misleading. For
example, a firm may offer below-cost prices to one side of a platform to attract more users on the
other side, where it charges above-cost prices.449 Looking only to one side of a two-sided market
may thus yield inaccurate conclusions about predation.450
Fourth, some have raised more general concerns about the role of antitrust in tech markets. This
strand of the literature builds on the error-cost framework originally developed by Frank
Easterbook,451 who relied on decision theory to argue that antitrust rules should err on the side of
permissiveness.452 Specifically, Easterbrook—who is now a federal judge—reasoned that
monopoly profits eventually induce the entry of new firms, mitigating the costs of judicial
decisions permitting anticompetitive conduct (false negatives or Type II errors).453 In contrast,
market forces cannot correct decisions condemning procompetitive conduct, leading Easterbrook
to conclude that the costs of those mistakes (false positives or Type I errors) are more durable.454

446 Evans & Schmalensee, supra note 444, at 24-26.
447 Id. To some extent, the doctrine may already accommodate this concern: some lower courts have recognized a
“meeting competition” defense to predation claims. ANTITRUST DEVELOPMENTS, supra note 55, at 301 (collecting
cases). In contrast, one district court has rejected this defense. Spirit Airlines, Inc. v. Northwest Airlines, Inc., 2003 WL
24197742 at *11-12 (E.D. Mich. 2003), rev’d on other grounds, 431 F.3d 917 (6th Cir. 2005). The Supreme Court has
not directly addressed the issue.
Advocates of more aggressive antitrust intervention have supported stricter predation standards for dominant tech
firms, but appear to leave open the possibility of a “meeting competition” defense. See Khan, Amazon’s Antitrust
Paradox, supra note 79, at 791-92 (advocating a “presumption of predation for dominant platforms found to be pricing
products below cost,” while suggesting a business justification defense that “could cover” prices that match
competition, among other things).
448 DENNIS W. CARLTON & JEFFREY M. PERLOFF, MODERN INDUSTRIAL ORGANIZATION 393 (2004).
449 Stefan Behringer & Lapo Filistrucchi, Areeda-Turner in Two-Sided Markets, 46 REV. OF INDUS. ORG. 287, 304
(2015); Amelia Fletcher, Predatory Pricing in Two-Sided Markets, 3 COMPETITION POL’Y INT’L 221, 222-23 (2007).
450 The Supreme Court’s 2018 Amex decision may have implications for this type of analysis. 138 S. Ct. 2274 (2018).
For a discussion of Amex, see supra “Amazon.”
451 Frank H. Easterbrook, The Limits of Antitrust, 63 TEX. L. REV. 1 (1984).
452 Decision theory is a field of microeconomics concerned with the process of making decisions under conditions of
costly and imperfect information. C. Frederick Beckner III & Steven C. Salop, Decision Theory and Antitrust Rules, 67
ANTITRUST L.J. 41, 41 (1999). The field gained initial traction in legal scholarship during the law-and-economics
movement of the 1970s and has proven particularly influential in antitrust. See Alan Devlin & Michael Jacobs,
Antitrust Error, 52 WM. & MARY L. REV. 75, 82-97 (2010).
453 Easterbrook, supra note 451, at 2.
454 Id.
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Several commentators have suggested that Easterbrook’s argument has particular force in
technology markets.455 They have appealed to what is often called the “inhospitality tradition” of
1960s antitrust—an era in which courts were highly skeptical of nonstandard agreements and
business conduct.456 In one narrative, once courts realized that many challenged practices had
benign or procompetitive explanations, the law underwent a needed course correction in which
context-specific inquiries into economic effects replaced the formalism of per se rules as the
dominant mode of antitrust analysis.457 Some argue that this history has implications for the
optimal level of intervention in tech markets, where generalist judges may mistake novel products
and business strategies for anticompetitive conduct.458
Others have come to the opposite conclusion. John Newman—formerly the Deputy Director of
the FTC’s Bureau of Competition—has argued that false negatives in tech markets are far more
common and costly than false positives.459 Newman contends that the structure of many digital
markets insulates incumbents from competitive threats; that digital markets provide incumbents
with unique anticompetitive strategies; and that challenged conduct in digital markets typically
has few redeeming benefits.460 These features, he maintains, justify more vigilant antitrust
scrutiny of tech markets, contrary to what he characterizes as the “orthodox” view of error
costs.461
Revisiting the Goals of Antitrust: The Neo-Brandeisian Movement
The optimal level of antitrust intervention—in tech markets and more generally—depends on the
underlying goals of antitrust law.462 As discussed, the last 40 years have been marked by a general
(though not complete) consensus that antitrust should be limited to promoting some conception of
economic welfare.463 While there are lingering disputes within the welfarist approach,464 modern

455 Joshua D. Wright & Murat C. Mungan, The Easterbrook Theorem: An Application to Digital Markets, 130 YALE
L.J. F. 622, 634 (2021); Geoffrey Manne, Error Costs in Digital Markets, in GLOBAL ANTITRUST INSTITUTE REPORT ON
THE DIGITAL ECONOMY (2020).
456 Elyse Dorsey, Anything You Can Do, I Can Do Better—Except in Big Tech?: Antitrust’s New Inhospitality
Tradition, 68 KANSAS L. REV. 975, 978, 981 (2020).
457 Id. at 985-89.
458 Rachel S. Tennis & Alexander Baier Schwab, Business Model Innovation and Antitrust Law, 29 YALE. J. ON REG.
307, 319-20 (2012).
459 John M. Newman, Antitrust in Digital Markets, 72 VAND. L. REV. 1497, 1502 (2019).
460 Id. at 1503-48.
461 Id. at 1502.
462 BORK, supra note 72, at 50 (“[A]ntitrust policy cannot be made rational until we are able to give a firm answer to
one question: What is the point of the law—what are its goals? Everything else follows from the answer we give. . . .
Only when the issue of goals has been settled is it possible to frame a coherent body of substantive antitrust rules.”);
Stucke, supra note 1, at 557 (making a similar point).
463 A. DOUGLAS MELAMED, ET AL., ANTITRUST LAW AND TRADE REGULATION: CASES AND MATERIALS 58 (7th ed. 2018)
(noting the “overall consensus” since the 1970s that “economic analysis provides the true north for antitrust law”);
ANTITRUST MODERNIZATION COMM’N, REPORT AND RECOMMENDATIONS 35 (Apr. 2007) (“For the last few decades
courts, agencies, and antitrust practitioners have recognized consumer welfare as the unifying goal of antitrust law.”);
POSNER, supra note 193, at ix (explaining that “[a]lmost everyone professionally involved in antitrust today—whether
as a litigant, prosecutor, judge, academic, or informed observer” agrees that “the only goal of the antitrust laws should
be to promote economic welfare”).
464 A. Douglas Melamed, Antitrust Law and Its Critics, 83 ANTITRUST L.J. 269, 274-79 (2020) (discussing several
points of disagreement between “conservatives” and “mainstream progressives” working within the consumer-welfare
tradition).
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doctrine generally eschews “non-economic” considerations like equity, the protection of small
businesses, and the promotion of democratic values.465
In the past decade, a group of scholars and activists commonly referred to as “Neo-Brandeisians”
has mounted a critique of this consensus.466 Members of this movement have argued that the
existing antitrust regime has failed to preserve competition, resulting in rising economic
concentration, growing wealth inequality, and a political system captured by corporate
interests.467 Their influence has not been limited to the academy; some self-described
Neo-Brandeisians—like FTC Chair Lina Khan and former White House advisor Tim Wu—have
occupied policymaking positions within the federal government.468
Two separate arguments are evident throughout Neo-Brandeisian scholarship.
First, Neo-Brandeisians deny that antitrust should serve only economic goals like consumer
welfare.469 Instead, they endorse a broader normative vision in which antitrust deconcentrates
markets, promotes fairness, and disperses economic and political power.470
Second, Neo-Brandeisians have argued that the consumer-welfare standard has failed even when
judged on its own terms. They allege that, in applying an exclusively economic approach to
antitrust, courts have embraced simplistic theories that downplay the harms from concentration
and the likelihood of exclusion, leading to uncompetitive markets with higher prices and
degraded quality.471 Some Neo-Brandeisians have argued that these putative deficiencies are
especially severe vis-à-vis large tech platforms, many of which are able to forgo immediate
profits to establish long-term dominance and then leverage that dominance across business
lines.472
This second set of arguments is not unique to Neo-Brandeisians. As discussed, the Post-Chicago
tradition challenged the laissez-faire prescriptions of Chicago School academics from within the
welfarist paradigm.473 Many commentators also continue to criticize current doctrine as unduly
permissive on economic grounds.474 The distinctiveness of the Neo-Brandeisian critique thus lies
in its call for an expansion of the range of antitrust goals—not its repudiation of conservative
economic theories.475
The key difficulty facing this project involves operational specifics. One of the central criticisms
of mid-20th century antitrust was that it allegedly offered no principled standard for weighing

465 Wright & Ginsburg, supra note 204, at 2406 (noting the 1970s shift in antitrust doctrine from an approach that
served “multiple masters” to one in which “economic goals would be exclusive”).
466 See, e.g., Sanjukta Paul, Recovering the Moral Economy Foundations of the Sherman Act, 131 YALE L.J. 175
(2021); Sandeep Vaheesan, The Profound Nonsense of the Consumer Welfare Standard, 64 ANTITRUST BULL. 479
(2019); TIM WU, THE CURSE OF BIGNESS: ANTITRUST IN THE NEW GILDED AGE (2018); Khan, Amazon’s Antitrust
Paradox, supra note 79.
467 Lina M. Khan & Sandeep Vaheesan, Market Power and Inequality: The Antitrust Counterrevolution and Its
Discontents, 11 HARV. L. & POL’Y REV. 235 (2017).
468 WU, supra note 466, at 127-40; Khan, supra note 208.
469 Vaheesan, supra note 466.
470 Khan & Vaheesan, supra note 467, at 276; HJC REPORT, supra note 11, at 391-92.
471 Khan, Amazon’s Antitrust Paradox, supra note 79, at 739.
472 Id. at 747-53, 774-80.
473 Yoo, supra note 195, at 2160.
474 Melamed, supra note 464, at 274-79.
475 Lina M. Khan, The End of Antitrust History Revisited, 133 HARV. L. REV. 1655, 1671 (2020) (“Post-Chicago’s
choice to accept Chicago’s normative paradigm stands in contrast with the New Brandeis intervention, which rejects
the idea that antitrust law should be centered on promoting consumer welfare.”).
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many of the conflicting goals that courts had read into the antitrust statutes.476 Some business
conduct, for example, may benefit consumers while harming a firm’s smaller rivals.477 An
antitrust regime that embraces both consumer welfare and small-business protection may thus
have difficulty trading off those values in a coherent fashion. Other constituencies—workers,
labor unions, potential entrants, existing competitors—may also have divergent interests.478
Adding abstract principles like fairness and democracy to the calculus could create even further
uncertainty.479
The Neo-Brandeisian response appears to involve a preference for bright-line rules over the type
of fact-intensive analysis employed by current law.480 Neo-Brandeisians may thus conceptualize
their favored goals as operating at the level of rule formulation, but not as factors that courts must
balance in individual cases.
It is unclear, however, whether Neo-Brandeisians intend to reduce all of antitrust doctrine to
bright-line rules.481 Moreover, as discussed below, some competition legislation directed at tech
platforms would stop short of adopting categorical prohibitions. Instead, it would proscribe
specified conduct only upon a showing of harm to “competition,” or ban specified conduct while
offering an affirmative defense to platforms that show the relevant activities do not harm
“competition.”482 If this language is not intended to denote a welfarist conception of competitive
harm, the ambiguities surrounding alternative understandings of “competition” resurface.
Several commentators—including some Neo-Brandeisians—have supported a “protection of the
competitive process” test as an alternative to the consumer-welfare standard.483 The details of this
approach, however, remain hazy.484 Some advocates have equated it with the promotion of

476 See, e.g., Joshua D. Wright, et al., Requiem for a Paradox: The Dubious Rise and Inevitable Fall of Hipster
Antitrust, 51 ARIZ. ST. L.J. 292, 300 (2019).
477 See Elhauge, supra note 42, at 268-69 (noting that “all desirable procompetitive behavior and innovation is intended
to harm rivals—driving those rivals out of the market by making a cheaper or better product is how firms earn the
monopoly profits that reward their investments and innovations in lowering costs and raising quality”).
478 Daniel A. Crane, Four Questions for the Neo-Brandeisians, COMPETITION POL’Y INT’L ANTITRUST CHRON. 63, 66-67
(Apr. 2018).
479 See HJC REPORT, supra note 11, at 391-92 (arguing that antitrust should protect, among other things, “a fair
economy” and “democratic ideals”); Zephyr Teachout, Antitrust Law, Freedom, and Human Development, 41
CARDOZO L. REV. 1081, 1105 (2019) (suggesting that democracy and “greater moral freedom” should be among the
goals that antitrust serves).
480 Khan & Vaheesan, supra note 467, at 276.
481 See Francis, supra note 63, at 788-89 (noting that “[t]he literature does not yet contain anything we could call a
Neo-Brandeisian theory of monopolization,” and that the movement has not produced a comprehensive account of what
unilateral conduct should be banned and why); DEVLIN, supra note 10, at 174 (arguing that, while Neo-Brandeisians
have advocated overturning certain decisions and eliminating certain enforcement policies, they have not identified
replacement rules or standards with a high degree of precision).
482 American Innovation and Choice Online Act, S. 2033, 118th Cong. §§ 3(a)(1)-(3), (b)(2) (2023).
483 SULLIVAN, ET AL., supra note 26, at 16-22; HJC REPORT, supra note 11, at 391-92; Tim Wu, The “Protection of the
Competitive Process” Standard, (Colum. Pub. L. Research Paper No. 14-612, 2018),
https://scholarship.law.columbia.edu/cgi/viewcontent.cgi?article=3293&context=faculty_scholarship; Khan, Amazon’s
Antitrust Paradox, supra note 79, at 745.
484 Herbert Hovenkamp, The Slogans and Goals of Antitrust Law 54 (U. Penn. Inst. for L. & Econ. Research Paper No.
22-33, 2022) (“[A]n antitrust concern articulated as the protection of the competitive process does not give us much
help unless we have some background substance to tell us what is intelligent competition policy and what is not.”);
Einer Elhauge, Should the Competitive Process Test Replace the Consumer Welfare Standard?, PROMARKET (May 24,
2022), https://www.promarket.org/2022/05/24/should-the-competitive-process-test-replace-the-consumer-welfare-
standard/ (arguing that a “competitive process” standard that lacks any supplemental benchmark “amounts to a
conclusory I-know-it-when-I-see-it test”); John M. Newman, Procompetitive Justifications in Antitrust Law, 94 IND.
(continued...)
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deconcentrated market structures.485 Jonathan Kanter—the Assistant Attorney General for the
DOJ’s Antitrust Division—has similarly described the “competitive process” as protecting “the
guarantee that everyone participating in the open market—consumers, farmers, workers, or
anyone else—has ‘the free opportunity to select among alternative offers.’”486
As legal standards, these formulations have been criticized for failing to offer meaningful
guidance to courts or litigants. It seems unlikely, for example, that they are intended to mean that
any conduct that reduces the number of competitors in a market should be illegal; that rule would
outlaw many instances of procompetitive price cutting and product improvement, in addition to
small mergers in unconcentrated markets.487 The proposals instead appear to endorse an approach
that ensures there are “enough” competitors, though it is not clear whether Neo-Brandeisians
would endorse the use of some further analytical criterion in evaluating whether a given market
has “enough” firms.488
Thus far, Neo-Brandeisian theories do not appear to have made considerable headway with the
courts.489 Some commentators, however, have argued that the movement’s influence is evident in
several developments at the antitrust agencies, including the FTC’s 2023 proposal to ban
non-compete clauses in employment contracts,490 the DOJ’s effort to revive its long-dormant
authority to pursue criminal monopolization charges,491 and the 2023 draft merger guidelines.492
Whether Neo-Brandeisian ideas will have a broader impact on antitrust doctrine or legislative
action remains to be seen.
Scoping Reform Proposals
As discussed, some legislative proposals would create special competition rules for large
technology platforms.
Two general models have emerged. One model involves special rules for digital platforms that
offer specified services and meet certain quantitative and qualitative criteria intended to capture

L.J. 501, 514 (2019) (“[T]he actual content of the competitive-process approach remains mercurial, a cipher. The
scholarly arguments in favor of it never seem to identify what, exactly, constitutes the ‘competitive process.’”).
485 Khan, Amazon’s Antitrust Paradox, supra note 79, at 745.
486 Assistant Att’y Gen. Jonathan Kanter Delivers Remarks at New York City Bar Association’s Milton Handler
Lecture (May 18, 2022), https://www.justice.gov/opa/speech/assistant-attorney-general-jonathan-kanter-delivers-
remarks-new-york-city-bar-association (quoting Nat’l Soc’y of Pro. Eng’rs v. United States, 435 U.S. 679, 695 (1978))
[hereinafter “Kanter Handler Lecture”].
487 Elhauge, supra note 484 (noting that a literalist conception of “competition” would “ban two plumbers, in a market
with 1,000 plumbers, from forming a partnership to offer better services,” and that this approach “would limit our
economy to atomistic competition between sole proprietors in a way that would massively reduce our productivity and
impede our economic liberty to collaborate with others in efficient ways”); DEVLIN, supra note 10, at 10 (“Maximizing
competition in the most simplistic sense of the term would be self-destructive.”).
488 Elhauge, supra note 484. Certain defenses of the “competitive process” approach appear to reject the use of
supplementary goals. See Kanter Handler Lecture, supra note 486 (indicating that “the question of the goals of antitrust
starts and ends” with “competition and the competitive process”) (emphasis added). Some commentators, however,
have interpreted Neo-Brandeisian scholarship as endorsing an approach that weighs multiple objectives, including
consumer welfare. See Thomas A. Lambert & Tate Cooper, Neo-Brandeisianism’s Democracy Paradox, 49 J. CORP. L.
_ (forthcoming 2023).
489 FRANCIS & SPRIGMAN, supra note 26, at 24.
490 Id.
491 Id.
492 DOJ and FTC Release Draft of New Merger Guidelines, MORRISON & FOERSTER LLP (July 27, 2023),
https://www.mofo.com/resources/insights/230727-doj-and-ftc-release-draft-of-new-merger-guidelines.
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platforms with bottleneck power over business users.493 Because proposals in this category
involve the designation of covered platforms by regulators, this report refers to this strategy as the
“designated-platform approach.”494
The second model is narrower. While the designated-platform approach would apply the same set
of rules to covered firms in a range of markets (e.g., social networking, e-commerce, online
search), some legislation would apply only to individual markets.495 This report refers to this
strategy as the “market-specific approach.”
The subsections below review these two models for sector-specific competition rules.
The Designated-Platform Approach
Policymakers in the United States and EU have explored the designated-platform approach. The
EU has adopted legislation called the Digital Markets Act, which applies special regulations to
designated “gatekeepers.”496 Firms are to be designated as “gatekeepers” if they offer certain
“core platform services”—including search engines, app stores, operating systems, advertising
services, social networking, and online marketplaces—and meet certain quantitative and
qualitative criteria.497
In the United States, several bills in the 117th Congress would have adopted a broadly similar
approach.498 One of those bills has been reintroduced in the 118th Congress,499 and other
legislation in the 118th Congress employs a comparable strategy.500
The proposals would empower a regulator to designate a platform offering any of the relevant
services as a covered platform based on (1) quantitative thresholds involving market
capitalization, annual sales, and active users, and (2) the platform’s status as a “critical trading
partner.”501

493 See infra “The Designated-Platform Approach.”
494 As drafted, some of these proposals would apply special regulations to platforms meeting the relevant criteria even
if the platforms are not formally designated by a regulator. See, e.g., American Innovation and Choice Online Act, S.
2033, 118th Cong. § 2(a)(5)(B) (2023). Nevertheless, this report adopts the terminology noted above because of the
central role that designation would likely play in the bills’ application.
495 See infra “The Market-Specific Approach.”
496 Press Release, Euro. Comm’n, Digital Markets Act: Rules for Digital Gatekeepers to Ensure Open Markets Enter
Into Force (Oct. 31, 2022), https://ec.europa.eu/commission/presscorner/detail/en/IP_22_6423.
497 Id.
498 American Innovation and Choice Online Act, S. 2992, 117th Cong. § 3(d) (2022) (Reported Version); Platform
Competition and Opportunity Act of 2021, S. 3197, 117th Cong. § 4 (2021); ACCESS Act of 2021, H.R. 3849, 117th
Cong. § 6 (2021); Platform Competition and Opportunity Act of 2021, H.R. 3826, 117th Cong. § 4 (2021); Ending
Platform Monopolies Act, H.R. 3825, 117th Cong. § 6 (2021); American Innovation and Choice Online Act, H.R.
3816, 117th Cong. § 2(d) (2021) (Reported Version).
499 American Innovation and Choice Online Act, S. 2033, 118th Cong. (2023).
500 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. (2023).
501 See, e.g., S. 2033 §§ 2(a)(5), 3(d).
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Different bills would impose different types of competition rules on designated platforms,
including rules involving discriminatory conduct against business users,502 vertical integration,503
and mergers.504
Depending on the interpretation of the “critical trading partner” standard, the designation criteria
may encompass the platforms discussed earlier in this report:
• Facebook, Instagram, and WhatsApp (which are controlled by Meta Platforms);
• Google Search, Android, the Google Play Store, and some of Google’s ad-tech
services;
• Amazon Marketplace; and
• Apple’s iOS and App Store.505
Certain Microsoft properties and TikTok—a short-form video app controlled by the Chinese firm
ByteDance—may also fall within the bills’ coverage.506
The designation criteria employed in these proposals raise several issues. Some commentators
have criticized the use of market capitalization and annual sales as factors that would determine a
firm’s regulatory status.507 Those criteria, they contend, have little relevance for a platform
operator’s ability to harm competition, which instead depends on a firm’s market power.508 As
discussed, courts typically assess claims of market power by evaluating a firm’s size within a
relevant antitrust market—not its absolute size.509 Critics of the designated-platform bills thus
argue that the proposals employ arbitrary designation criteria intended to single out a small
handful of companies.510
The bills seek to address some of these concerns about arbitrariness with the additional
requirement that covered platforms include only “critical trading partners”—a term defined to
mean persons with the ability to “restrict or impede” a business user’s access to customers or

502 S. 2992; H.R. 3816.
503 H.R. 3825.
504 H.R. 3826. Another proposal—which would have imposed interoperability and data-portability obligations on
covered platforms—employed the same general designation standards as the other bills, but would have provided for
firm-specific standards rather than uniform regulatory treatment of covered firms. H.R. 3849.
505 Leah Nylen, Tech Antitrust Bill Threatens to Break Apple, Google’s Grip on the Internet, BLOOMBERG (July 26,
2022), https://www.bloomberg.com/graphics/2022-tech-antitrust-bill/#xj4y7vzkg.
506 Id.
507 Erik Hovenkamp, Proposed Antitrust Reforms in Big Tech: What Do They Mean for Competition and Innovation?,
COMPETITION POLICY INT’L ANTITRUST CHRONICLE 15, 22 (July 2022) [hereinafter “Hovenkamp, Proposed Antitrust
Reforms”]; AURELIAN PORTUESE, INFO. TECH. & INNOVATION FDN., THE REVISED (BUT UNCORRECTED) VERSION OF THE
KLOBUCHAR BILL (2022), https://www2.itif.org/2022-revised-uncorrected-klobuchar-bill.pdf; Comments of the
American Bar Association Antitrust Law Section Regarding the American Innovation and Choice Online Act (S. 2992)
Before the 117th Congress 8 (Apr. 27, 2022), https://www.americanbar.org/content/dam/aba/
administrative/antitrust_law/comments/at-comments/2022/comments-aico-act.pdf [hereinafter “ABA Letter”].
508 Hovenkamp, Proposed Antitrust Reforms, supra note 507, at 22; PORTUESE, supra note 507; ABA Letter, supra note
507, at 8.
509 ELHAUGE, supra note 38, at 226.
510 E.g., Herbert Hovenkamp, Gatekeeper Competition Policy 18 (U. of Penn., Inst. for L. & Econ., Research Paper No.
23-08, 2023), https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4347768 [hereinafter “Hovenkamp, Gatekeeper
Competition Policy”] (arguing that the strategy of designating platforms based on size rather than market share suggests
an intent to protect the rivals of covered platforms from aggressive competition rather than a desire to protect
consumers); PORTUESE, supra note 507.
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tools or services needed to effectively serve customers.511 This phrase would represent a novel
addition to the antitrust lexicon.
The use of the new “critical trading partner” language instead of the more familiar concept of
market power may be a response to some of the more demanding elements of market-power
doctrine. Market definition—which is required if a plaintiff seeks to establish market power via
indirect evidence—often involves a costly and time-consuming battle of economic experts.512 The
“critical trading partner” terminology may be motivated in part by a desire to ease these burdens.
Some commentators have also lodged theoretical objections to the centrality of market definition
in contemporary antitrust.513 Among other things, they have highlighted the limitations of binary
market analysis when it comes to differentiated products.514 Products that fall within a relevant
antitrust market, for example, all count as equally effective substitutes for the product at issue; the
market-definition paradigm does not consider different rates of substitution among products
within a relevant market.515 Similarly, firms deemed to fall outside a relevant market are treated
as if they exert no competitive pressure on a defendant.516
Reality is often more nuanced. In markets with differentiated products—like many technology
markets—there may be a range of firms that compete with a defendant to various degrees.
Singling out a specific market boundary along this type of continuum may thus yield inaccurate
assessments of market power.517
The “critical trading partner” requirement thus appears to respond to dissatisfaction with existing
law. However, the requirement’s precise relationship with current doctrine is unclear. The core
concern of market definition—the availability of reasonable substitutes—seems relevant to
whether a platform has the ability to “restrict or impede” a business user’s access to customers or
necessary tools. As a result, some of the considerations that figure in market definition would
potentially play a role in evaluations of the “critical trading partner” requirement. The exact ways
in which this inquiry may differ from traditional market definition accordingly remain uncertain.
The literature also reflects different views of the requirement’s stringency. Some commentators
have argued that the relevant bills are “carefully targeted” because they would apply only to

511 E.g., American Innovation and Choice Online Act, H.R. 3816, 117th Cong. §§ 2(g)(4)(B)(iii), 2(g)(5) (2021)
(Reported Version).
512 See Hovenkamp, The Rule of Reason, supra note 31, at 98-99 (discussing the administrative costs associated with
the rule of reason); John E. Lopatka & William H. Page, Economic Authority and the Limits of Expertise in Antitrust
Cases, 90 CORNELL L. REV. 617, 659-60 (2005) (noting that modern courts recognize that “market definition requires
the sophisticated use of data and theory,” which in turn requires expert testimony).
513 Louis Kaplow, Why (Ever) Define Markets?, 124 HARV. L. REV. 437, 476-79 n.78-79 (2010) (cataloguing academic
criticisms of the role that market definition plays under current law).
514 Hovenkamp, Platform Monopoly, supra note 367, at 1961 (“If a market is product-differentiated, any conclusion
about market definition is wrong.”); Joseph Farrell & Carl Shapiro, Antitrust Evaluation of Horizontal Mergers: An
Economic Alternative to Market Definition, 10 B.E. J. OF THEORETICAL ECON. art. 9 at 4 (2010) (“Product
differentiation can make defining the relevant market problematic, notably because products must be ruled ‘in’ or ‘out,’
creating a risk that the outcome of a merger investigation or case may turn on an inevitably artificial line-drawing
exercise.”).
515 Hovenkamp, Platform Monopoly, supra note 367, at 1961.
516 Id.
517 See DEVLIN, supra note 10, at 281-84; Franklin M. Fisher, Diagnosing Monopoly, 19 Q. REV. ECON. & BUS. 7, 16
(1979) (“By focusing on whether products are in or out of the market, one converts a necessarily continuous question
into a question of yes or no.”).
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“critical trading partners.”518 Others have contended that the additional criterion is unlikely to
exclude firms that meet the bills’ quantitative thresholds.519 The analytical framework governing
assessments of the “critical trading partner” standard would thus have to be fleshed out in
practice, if Congress were to enact legislation employing that concept.520
The use of the “critical trading partner” language instead of a market-power requirement is not
inherent to the designated-platform approach. In empowering a regulator to designate platforms
for special competition regulation, Congress could consider limiting designations to firms that
possess significant market power.
In the 117th Congress, S. 1074 would have taken that approach.521 The bill would have imposed
special merger rules on “dominant digital firms”—a term defined to mean companies that provide
online services and possess “dominant market power” in any market related to such services.522
Under the legislation, the FTC would have been empowered to designate companies as “dominant
digital firms” based on their possession of “dominant market power” and several other factors,
including network effects, use of exclusivity agreements, and vertical integration.523
Besides these issues involving designation criteria, the designated-platform approach implicates
the broader question of whether the Big Tech firms (and any other designated firms) are
sufficiently similar to warrant uniform regulatory treatment. As discussed, some commentators
have argued that certain platform markets share structural similarities that justify a consistent
regulatory response, while others have emphasized the differences between those markets. For
proponents of new competition regulations, that issue may be the central question that determines
the choice between the designated-platform approach and market-specific regulation.

518 Letter from Fiona M. Scott Morton, et al., to Sen. Amy Klobuchar & Sen. Charles Grassley 1 (July 7, 2022),
https://som.yale.edu/sites/default/files/2022-07/AICOA-Final-revised.pdf (“[S. 2992’s] approach is carefully targeted
in that its prohibitions apply only to platforms deemed ‘critical trading partners’—meaning they have the power to
deprive business users of access to customers or access to inputs necessary for those users to run their businesses. The
result is that [S. 2992’s] restrictions apply to the platforms whose market positions confer undue gatekeeping power,
and no others.”).
519 Monika Schnitzer, et al., International Coherence in Digital Platform Regulation: An Economic Perspective on the
US and EU Proposals, YALE TOBIN CTR. FOR ECON. POLICY 9 (Aug. 9, 2021), https://tobin.yale.edu/sites/
default/files/Coherence%20in%20Digital%20Platform%20Regulation.pdf; see also Reining in Dominant Digital
Platforms: Restoring Competition to Our Digital Markets, Hearing Before the Subcomm. on Competition Policy,
Antitrust and Consumer Rights of the S. Comm. on the Judiciary (Mar. 7, 2023) (testimony of Daniel Francis, Assistant
Professor of Law, New York University School of Law at 85), https://www.judiciary.senate.gov/imo/media/doc/2023-
03-07%20-%20Testimony%20-%20Francis.pdf [hereinafter “Francis Testimony”] (arguing that the definition of
“critical trading partner” in the American Innovation and Choice Online Act is “strikingly broad and vague,” and that it
“appears to encompass any business that offers a desirable means of reaching customers for even a single business
user”).
520 One commentator has proposed a potentially similar test for identifying dominant platforms without resorting to
traditional market-power analysis. The relevant proposal would subject platforms to special competition regulations
based on an assessment of their “cost of exclusion”—a concept that measures the costs to an individual or business of
being excluded from a platform. HAROLD FELD, ROOSEVELT INST., THE CASE FOR THE DIGITAL PLATFORM ACT: MARKET
STRUCTURE AND REGULATION OF DIGITAL PLATFORMS 41-47 (May 8, 2019), https://rooseveltinstitute.org/wp-
content/uploads/2020/07/RI-Case-for-the-Digital-Platform-Act-201905.pdf. For a discussion of the mathematics
involved in calculating a firm’s “cost of exclusion,” see id. at 43-44.
521 Trust-Busting for the Twenty-First Century Act, S. 1074, 117th Cong. § 4 (2021).
522 Id.
523 Id.
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The Market-Specific Approach
Some proposals for sectoral competition regulation rely on a more targeted strategy than the
designated-platform approach. Instead of applying the same set of rules to designated firms
operating across a range of different tech markets, policymakers could adopt regulations tailored
to individual markets. In recent years, lawmakers have introduced bills targeting two industries:
app stores and digital advertising.524
In the 117th Congress, the Open App Markets Act (OAMA) would have established competition
rules for large app stores.525 Among other things, the legislation would have prohibited operators
of covered app stores from tying their app stores to their payment processors; preferencing their
own apps in search results; and using nonpublic information derived from third-party apps to
compete with those apps.526 The bill’s requirements are discussed in greater detail in “Ex Ante
Conduct Rules” infra.
In the 118th Congress, the Advertising Middlemen Endangering Rigorous Internet Competition
Accountability (AMERICA) Act would impose structural-separation requirements and conduct
rules on certain digital-advertising platforms.527 The legislation would prohibit firms with more
than $20 billion in annual digital-advertising revenue from owning platforms that operate in more
than one of the key nodes in the ad-tech supply chain (ad exchanges, sell-side brokerages, and
buy-side brokerages).528 It would also require firms with more than $5 billion in annual
digital-advertising revenue to abide by customer-protection rules involving best execution and
transparency.529
Enforcement
Reform proposals have taken different approaches to issues of enforcement.
In the 118th Congress, the Digital Consumer Protection Commission Act (DCPCA) would
establish a new federal agency tasked with regulating large online platforms.530 The new agency
would have a broad mandate covering competition, transparency, privacy, and national security
issues.531
On the competition front, the DCPCA would charge the new agency with enforcing prohibitions
of abuses of dominance532 and conflicts of interest,533 in addition to granting the agency the
authority to block platform mergers under a public-interest standard.534

524 Advertising Middlemen Endangering Rigorous Internet Competition Accountability Act, S. 1073, 118th Cong.
(2023); Open App Markets Act, S. 2710, 117th Cong. (2022) (Reported Version); Competition and Transparency in
Digital Advertising Act, H.R. 7839, 117th Cong. (2022); Open App Markets Act, H.R. 7030, 117th Cong. (2022);
Open App Markets Act, H.R. 5017, 117th Cong. (2021).
525 S. 2710; H.R. 7030; H.R. 5017.
526 S. 2710 § 3; H.R. 7030 § 3; H.R. 5017 § 3.
527 S. 1073.
528 Id. § 2.
529 S. 1073.
530 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2111 (2023).
531 Id. §§ 2201-2321, 2411-2503.
532 Id. § 2311.
533 Id. § 2312.
534 Id. § 2313.
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The bill’s abuse-of-dominance provision would make it unlawful for a covered platform operator
to abuse its dominance or “otherwise engage in conduct that harms competition or creates or
helps maintain an unfair method of competition, a monopoly, or a monopsony, regardless of any
alleged procompetitive benefit or efficiencies.”535 While the legislation identifies several practices
as presumptive violations of this prohibition, it would also give the new agency rulemaking
authority to identify additional practices as presumptive violations.536 Platforms could rebut a
presumptive violation with clear and convincing evidence that their conduct “did not result in any
harm to the relevant aggrieved party.”537
Other proposals adopt a different approach. As discussed, several bills in the 117th Congress (one
of which has been reintroduced in the 118th Congress) would have empowered the DOJ and FTC
to designate firms based on certain quantitative and qualitative criteria.538 Designated firms would
then be subject to special competition rules. The bills would have charged the DOJ and FTC with
enforcing the relevant prohibitions in federal court, but would not have given the agencies
rulemaking authority to expand or clarify their scope.
Reform Proposals
This final section of the report discusses the substance of various proposals to reform the
competition laws governing Big Tech platforms. The proposals fall into five categories:
(1) ex ante conduct rules, (2) structural separation and line-of-business restrictions, (3) special
merger rules, (4) interoperability and data-portability mandates, and (5) changes to general
antitrust doctrine.
Ex Ante Conduct Rules
As discussed, some commentators have advocated the adoption of prophylactic conduct rules for
Big Tech platforms, which would supplement general antitrust law. This subsection reviews
several of these proposals for ex ante competition regulation.
Self-Preferencing
The ability of large digital platforms to preference their own offerings is a recurring concern in
debates over antitrust reform. As discussed, several of the Big Tech firms have been accused of
engaging in various forms of self-preferencing. Google has allegedly favored its own verticals in
general search results; its own app store and apps through its control of Android; and its own
ad-tech businesses through its presence in multiple segments of the ad-tech market.539 Apple has

535 Id. § 2311(b). The “abuse of dominance” language is borrowed from EU competition law, which generally reflects a
more restrictive approach to the unilateral conduct of dominant firms than U.S. antitrust law. See DANIEL J. GIFFORD &
ROBERT T. KUDRLE, THE ATLANTIC DIVIDE IN ANTITRUST: AN EXAMINATION OF US AND EU COMPETITION POLICY
63-196 (2015).
536 S. 2597 § 2311(e).
537 Id. § 2311(d).
538 American Innovation and Choice Online Act, S. 2033, 118th Cong. § 3(d) (2023); American Innovation and Choice
Online Act, S. 2992, 117th Cong. § 3(d) (2022) (Reported Version); Platform Competition and Opportunity Act of
2021, S. 3197, 117th Cong. § 4 (2021); Platform Competition and Opportunity Act of 2021, H.R. 3826, 117th Cong.
§ 4 (2021); Ending Platform Monopolies Act, H.R. 3825, 117th Cong. § 6 (2021); American Innovation and Choice
Online Act, H.R. 3816, 117th Cong. § 2(d) (2021) (Reported Version).
539 See supra “Google.”
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likewise been accused of preferencing its own apps and app store,540 while Amazon has allegedly
privileged its own private-label products and products that use its fulfillment services.541
The primary concern with this type of conduct involves monopoly leveraging.542 As discussed,
leveraging theories of harm can take two forms. Offensive leveraging occurs when a firm
attempts to use monopoly power in a primary market to extract additional profits from a
secondary market.543 By contrast, defensive leveraging involves the use of monopoly power to
gain an advantage in a secondary market so as to preserve a primary market monopoly—for
example, by eliminating competitive threats that might emerge from the secondary market.544
Defensive leveraging may be a viable theory of harm under existing monopolization law.545
Offensive-leveraging claims, however, cannot succeed under Section 2 absent evidence that a
defendant had a dangerous probability of monopolizing a secondary market; mere harm to
competition in the secondary market is not sufficient.546
For some of the self-preferencing allegations against Big Tech firms, these limitations may
preclude antitrust claims.547 It may be unlikely, for example, that Amazon will achieve monopoly
power over most of the products that it sells on its marketplace. As a result, it would be difficult
to challenge the preferential display of those products under an offensive-leveraging theory.548
This type of alleged favoritism may also be a weak foundation for a defensive-leveraging or
monopoly-maintenance case; it is not clear that Amazon’s elevation of allegedly inferior products
would help it maintain a putative e-commerce monopoly.
Similarly, the case law governing refusals to deal may serve as an impediment to antitrust claims
challenging platform self-preferencing. A platform operator’s favorable treatment of its own
verticals relative to rivals that use its platform is typically less harmful to rivals than an outright
refusal of access.549 Because antitrust imposes access duties only in a narrow set of
circumstances, courts would likely find many forms of self-preferencing to be permissible if such
conduct is evaluated as a refusal to deal.550

540 See supra “Apple.”
541 See supra “Amazon.”
542 See generally Todd, supra note 319.
543 GIUSEPPE COLANGELO, INT’L CTR. FOR L. & ECON., ANTITRUST UNCHAINED: THE EU’S CASE AGAINST
SELF-PREFERENCING (2022), https://laweconcenter.org/resources/antitrust-unchained-the-eus-case-against-self-
preferencing/?doing_wp_cron=1675175836.8782548904418945312500.
544 Robin Cooper Feldman, Defensive Leveraging in Antitrust, 87 GEO. L.J. 2079, 2080 (1999); Matthew Levinton,
Defensive Leveraging as Monopolization, AM. BAR ASS’N (June 22, 2022), https://www.americanbar.org/groups/
antitrust_law/resources/newsletters/defensive-leveraging-as-monopolization.
545 See United States v. Microsoft, 253 F.3d 34, 67 (D.C. Cir. 2001) (per curiam).
546 Verizon Commc’ns Inc. v. L. Offs. of Curtis V. Trinko, LLP, 540 U.S. 398, 410 n.4 (2004); see also Levinton,
supra note 544.
547 See GREGORY J. WERDEN, THE FOUNDATIONS OF ANTITRUST: EVENTS, IDEAS, AND DOCTRINES 355 (2020) (discussing
leveraging claims under U.S. law and concluding that “[s]elf-preferencing by digital platform monopolists will be
minimally constrained in the United States unless Congress creates a new regulatory structure for digital platforms”).
548 Herbert J. Hovenkamp, Monopolizing and the Sherman Act 32 (Penn. Carey L. Sch., Research Paper, No. 2769,
2022), https://scholarship.law.upenn.edu/cgi/viewcontent.cgi?article=3772&context=faculty_scholarship.
549 Erik Hovenkamp, The Antitrust Duty to Deal in the Age of Big Tech, 131 YALE L.J. 1483, 1546 (2022).
550 Trinko, 540 U.S. at 409. Refusal-to-deal doctrine is discussed in greater detail in supra “Refusals to Deal.” The
essential-facilities doctrine is also unlikely to preclude many forms of platform self-preferencing for a variety of
reasons, even if that doctrine remains good law. For an overview of the difficulties facing an essential-facilities
challenge to “search bias,” for example, see Marina Lao, Search, Essential Facilities, and the Antitrust Duty to Deal,
11 NW. J. TECH. & INTELL. PROP. 275, 298-304 (2013).
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In the 118th Congress, the American Innovation and Choice Online Act (AICOA) would respond
to these doctrinal difficulties by prohibiting covered platform operators from preferencing their
own products and services “in a manner that would materially harm competition.”551
Given the ubiquity of self-preferencing by vertically integrated firms, the meaning of the
“materially harm competition” standard is key to assessing the prohibition’s scope. However,
many argue the meaning of that language is not clear.552 The bill does not by its terms clarify
whether the “materially harm competition” standard embodies a consumer-welfare test or one of
the alternative standards for assessing competitive harm urged by proponents of antitrust
reform.553 As a result, it is unclear whether the AICOA would permit defendants to justify
challenged conduct on the ground that it benefits consumers.
If the AICOA becomes law, this may be a dispositive issue in many litigated cases. A wide range
of platform self-preferencing may harm a firm’s rivals while also offering consumer benefits. For
example, when Google displays a Google Maps result in response to a search query, it may
disadvantage rival map services, but benefit consumers.554 Apple’s preinstallation of its own apps
on iPhones, Microsoft’s inclusion of certain apps with its Windows operating system, and
Amazon’s free provision of its video-streaming service to Amazon Prime members may have
similar effects.555
It is not clear how the “materially harm competition” standard would apply to such practices. In
cases that do not involve per se offenses, Sherman Act defendants typically have the opportunity
to defend challenged conduct on the ground that it benefits consumers.556 To the extent that the
“materially harm competition” standard is intended to incorporate prevailing concepts of
competitive harm from the antitrust case law, then, consumer-welfare arguments would likely be
cognizable.

551 American Innovation and Choice Online Act, S. 2033, 118th Cong. § 3(a)(1) (2023). Versions of the AICOA were
also introduced in the 117th Congress. American Innovation and Choice Online Act, S. 2992, 117th Cong. (2022)
(Reported Version); American Innovation and Choice Online Act, H.R. 3816, 117th Cong. (2021) (Reported Version).
The OAMA included a more limited prohibition of self-preferencing related to app-store search results. The bill would
have prohibited covered firms from “unreasonably preferencing or ranking” their own apps in search results. Open App
Markets Act, S. 2710, 117th Cong. § 3(e)(1) (2022) (Reported Version); Open App Markets Act, H.R. 7030, 117th
Cong. § 3(e)(1) (2021); Open App Markets Act, H.R. 5017, 117th Cong. § 3(e)(1) (2021).
552 Hovenkamp, Gatekeeper Competition Policy, supra note 510, at 24; A. Douglas Melamed, Why I Think Congress
Should Not Enact the American Innovation and Choice Online Act, COMPETITION POLICY INT’L (June 19, 2022),
https://www.competitionpolicyinternational.com/why-i-think-congress-should-not-enact-the-american-innovation-and-
choice-online-act/; ABA Letter, supra note 507, at 5, 9-11.
553 Francis Testimony, supra note 519, at 55 (“‘[H]arm to competition’ is just not a phrase with a single self-executing
meaning. It could be interpreted to mean welfare harm in a manner we would associate with traditional antitrust; or it
could be interpreted to mean ‘injury to rivals[.]’”) (emphasis in original); Hovenkamp, Gatekeeper Competition Policy,
supra note 510, at 23-24 (“If competition is defined in an economically sensible way to refer to reduced market output
and higher prices, then the statute might end up limiting its reach to conduct posing a realistic threat of competitive
harm. If it means something else, such as merely injuring a rival or placing it at a disadvantage on that particular
platform as opposed to the market as a whole, then it could end up doing a great deal of harm.”); see also SULLIVAN, ET
AL., supra note 26, at 13 (noting that the term “competition” can refer to different and inconsistent goals, including
“structural numerosity,” the protection of small businesses for their own sake, markets in which no single actor can
influence price or output, and markets that are “efficient” on some measure).
554 Cf. Statement of the Federal Trade Commission Regarding Google’s Search Practices, In the Matter of Google Inc.,
No. 111-0163 at 3 (FTC Jan. 3, 2013) (concluding that Google’s display of its own content at or near the top of search
results “could plausibly be viewed as an improvement in the overall quality of Google’s search product”).
555 Francis Testimony, supra note 519, at 26.
556 See, e.g., United States v. Microsoft Corp., 253 F.3d 34, 59 (D.C. Cir. 2001) (per curiam).
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In interpreting other industry-specific competition statutes, however, some courts and
commentators have taken the view that “harm to competition” encompasses types of harm
beyond those proscribed by the antitrust laws.557 Additionally, some of the AICOA’s proponents
have rejected suggestions to amend the bill to adopt a consumer-welfare test.558
An interpretation that eschewed consumer-welfare justifications would also be consistent with the
normative vision articulated by many advocates of antitrust reform. As discussed, the role that
consumer welfare is meant to play in non-welfarist conceptions of “competition” is not clear.559
Much of the reformist literature, though, appears to reject the idea that courts and enforcers
should balance different antitrust goals against one another.560 This context, along with the bill’s
omission of other traditional antitrust concepts like market power, may cut against the argument
that consumer-welfare arguments would be cognizable under the “materially harm competition”
standard.561
The DCPCA appears to be more explicit about this issue. That legislation would make it
presumptively unlawful for covered platforms to preference their own products and services,
“regardless of any alleged procompetitive benefits or efficiencies.”562 Defendants could rebut an
allegation of unlawful self-preferencing only by establishing by clear and convincing evidence
that their conduct “did not result in any harm to the relevant aggrieved party.”563

557 Michael Kades, Protecting Livestock Producers and Chicken Growers: Recommendations for Reinvigorating
Enforcement of the Packers and Stockyards Act, WASH. CTR. FOR EQUITABLE GROWTH 48-57 (May 2022) (explaining
that some courts have equated “harm to competition” under the Packers and Stockyards Act with anticompetitive harm
under the antitrust laws, while others have adopted a broader interpretation).
558 Hearing Transcript at 39-40, Reining in Dominant Digital Platforms: Restoring Competition to Our Digital Markets,
Hearing Before the Subcomm. on Competition Policy, Antitrust and Consumer Rights of the S. Comm. on the Judiciary
(Mar. 7, 2023) (on file with author).
559 See supra “Revisiting the Goals of Antitrust: The Neo-Brandeisian Movement.”
560 See Marshall Steinbaum & Maurice E. Stucke, The Effective Competition Standard: A New Standard for Antitrust,
87 U. CHI. L. REV. 595, 604 (2020) (proposing an “effective competition” standard under which “a substantial lessening
of competition suffices for liability,” and “[e]nforcers and courts need not . . . balance the harms to one set of
stakeholders against the supposed benefits for another”); see also Kanter Handler Lecture, supra note 486 (indicating
that “the question of the goals of antitrust starts and ends” with “competition and the competitive process”) (emphasis
added); Khan & Vaheesan, supra note 467, at 276 (arguing that “[t]he shift from per se rules and presumptions to the
rule of reason and other standards-based tests has dramatically undercut antitrust enforcement,” and that “antitrust
doctrine should be simplified to ease enforcement and avoid interminable and largely fruitless inquiries into market
dynamics”).
561 The 117th Congress’s consideration of the AICOA featured discussion of the availability of a consumer-welfare
defense. The House Judiciary Committee ultimately adopted an amendment offering an affirmative defense under
which platform operators could avoid liability if they established by clear and convincing evidence that their conduct
would increase consumer welfare. American Innovation and Choice Online Act, H.R. 3816, 117th Cong. § 2(c)(3)
(2021) (Reported Version).
The relationship between the “materially harm competition” test and the consumer-welfare standard was also discussed
during the Senate Judiciary Committee’s markup of the AICOA. Transcript of Markup of S. 2992 at 53 (Jan. 20, 2022)
(on file with author) [hereinafter “S. 2992 Markup Transcript”] (Sen. Thom Tillis) (“It’s not clear how existing
competitor or competition jurisprudence would support or be changed by [S. 2992]. The purpose of competition law is
to eliminate harm to consumers not to pick winners and losers. I’m also aware of the spirited debate [over] whether
decades of antitrust law based on [the] consumer-welfare standard should be put in the burn pit. I’m open to having [a]
separate discussion about potential changes to that standard and I hope that we will. But as it stands in relation to this
bill, what standard will enforcers look to[?] What about amendments [that] would insert [the] consumer welfare
standard back into the definition of material harm to competition?”).
562 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2311(b), (c)(3) (2023).
563 Id. § 2311(d).
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Tying
The AICOA, OAMA, and DCPCA also contain provisions prohibiting tying in certain
circumstances.
The AICOA would bar covered platform operators from tying access to or preferred placement on
their platforms to the purchase or use of other products or services that are not “part of or intrinsic
to” a platform.564 The legislation would offer an affirmative defense, however, for conduct that
does not result in “material harm to competition.”565
The OAMA included a narrower tying provision. The bill would have prohibited covered firms
from conditioning access to their app stores on the use of their payment processors for in-app
transactions.566
The DCPCA’s tying provision is the broadest of the three bills. It would presumptively prohibit
covered platforms from engaging in tying, while offering platforms the ability to rebut an alleged
violation with clear and convincing evidence that their conduct “did not result in any harm to the
relevant aggrieved party.”567
All three bills go beyond current tying law. As discussed, the modified per se rule against tying
allows a plaintiff to prevail by showing that
1. The defendant offered two distinct products;
2. The defendant conditioned the sale of one product (the tying product) on the
purchase of the other product (the tied product);
3. The defendant possessed sufficient economic power in the tying product market
to coerce purchasers into acceptance of the tied product; and
4. The defendant’s conduct affected a “not insubstantial” amount of interstate
commerce in the tied product.568
Additionally, some courts have required plaintiffs to demonstrate that a tying arrangement had
anticompetitive effects in the tied product market,569 while others have entertained business
justifications for challenged ties.570 Two cases—the Ninth Circuit’s recent decision in Epic Games
v. Apple and the D.C. Circuit’s 2001 Microsoft decision—have also held that the rule of reason,
rather than the modified per se rule, applies to ties involving platform software.571

564 American Innovation and Choice Online Act, S. 2033, 118th Cong. § 3(a)(5) (2023).
565 Id. § 3(b)(2).
566 Open App Markets Act, S. 2710, 117th Cong. § 3(a)(1) (2022) (Reported Version); Open App Markets Act, H.R.
7030, 117th Cong. § 3(a)(1) (2021); Open App Markets Act, H.R. 5017, 117th Cong. § 3(a)(1) (2021).
567 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2311(c)(2), (d) (2023). The
DCPCA’s definition of “self-preferencing” also borrows language from the AICOA’s tying provision, defining that
term to include “conditioning access to the platform or preferred status or placement on the platform on the purchase or
use of other products or services offered by the covered platform operator.” Id. § 2311(a)(5)(D). A tying arrangement
employed by a covered platform may thus constitute a presumptive violation of the DCPCA on two independent
grounds.
568 HOVENKAMP, FEDERAL ANTITRUST POLICY, supra note 94, at 435 (summarizing the test employed by most federal
circuit courts of appeals).
569 Id. at 435-36.
570 E.g., Mozart Co. v. Mercedes-Benz of N. Am., Inc., 833 F.2d 1342, 1348 (9th Cir. 1987); Dehydrating Process Co.
v. A.O. Smith Corp., 292 F.2d 653, 655-57 (1st Cir. 1961).
571 Epic Games, Inc. v. Apple, Inc., 67 F.4th 946, 997 (9th Cir. 2023); United States v. Microsoft, 253 F.3d 34, 89-90
(D.C. Cir. 2001) (per curiam).
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In addition to ties involving app stores and payment processors, the tying provisions in the
AICOA and DCPCA may implicate several of the practices discussed earlier in this report,
including some of Google’s conduct in ad-tech markets and the link between favorable placement
on Amazon’s marketplace and use of Amazon’s fulfillment services.572
Interoperability and Data Access
Other proposals involve the ability of business users to interoperate with and access data they
generate on covered platforms.
The AICOA includes an interoperability provision that would prohibit covered platform operators
from restricting or impeding the ability of business users to interoperate with features that are
available to the operator’s own products or services, except where such access would lead to a
“significant cybersecurity risk.”573 Among other conduct, the prohibition may be directed at
Facebook’s alleged refusal to allow certain app developers to access Facebook Platform and
Apple’s alleged refusal to allow developers to access some APIs and device functionalities that
are available to Apple’s apps.574
The AICOA’s data-access provision would prohibit covered platform operators from restricting or
impeding a business user from accessing or transferring data generated by the user’s activities on
a covered platform.575
The OAMA also contained interoperability requirements. The bill would have required covered
companies to allow users of their operating systems to install third-party apps and app stores
through means other than the covered companies’ app stores.576 It also would have mandated that
covered firms provide developers with access to operating-system interfaces, development
information, and hardware and software features on terms that are functionally equivalent to those
that covered firms offer to their own apps.577
The DCPCA contains both interoperability and data-portability mandates for covered platforms.
The bill’s interoperability provision would require covered platform operators to
• allow business users to interoperate with hardware and software features that are
available to services on a covered platform provided by the platform operator;
• provide business users with continuous and real-time access to data generated by
the use of certain platform services; and
• provide business users with the necessary tools to access and analyze data on a
covered platform without a transfer from the platform.578
The DCPCA’s data-portability provision would require covered platform operators to maintain a
set of interfaces that provide users with “effective portability” of the data they generate using
certain platform services.579

572 See supra “Google” & “Amazon.”
573 American Innovation and Choice Online Act, S. 2033, 118th Cong. § 3(a)(4) (2023).
574 See supra “Meta Platforms” & “Apple.”
575 S. 2033 § 3(a)(7).
576 Open App Markets Act, S. 2710, 117th Cong. § 3(d)(2) (2022) (Reported Version); Open App Markets Act, H.R.
7030, 117th Cong. § 3(d)(2) (2021); Open App Markets Act, H.R. 5017, 117th Cong. § 3(d)(2) (2021).
577 S. 2710 § 3(f); H.R. 7030 § 3(f); H.R. 5017 § 3(f).
578 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2321(b) (2023).
579 Id. § 2321(a).
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Other, potentially broader interoperability and data-portability legislation is discussed in greater
detail in “Interoperability & Data Portability” infra.
Use of Nonpublic User Data
As discussed, some Big Tech firms have been accused of using their access to user data to
identify and imitate popular offerings. Amazon, for example, has allegedly used nonpublic data to
find profitable opportunities for its own private-label business.580 Apple has similarly been
accused of using competitively sensitive information to replicate fast-growing apps and integrate
certain functionalities into iOS.581
Some proposals would prohibit this conduct. The AICOA includes a provision that would bar
covered companies from using nonpublic data from dependent businesses to support their own
offerings.582 The OAMA included a similar prohibition.583
These types of measures have been debated. Some commentators have argued that a platform
operator’s imitation of rival products typically increases static efficiency by stimulating
competition and lowering prices.584 Others have argued that a ban on the use of nonpublic data by
platform operators would boost dynamic efficiency by protecting the incentives of other
businesses to innovate.585
Most-Favored-Nation Policies
Another general category of proposals involves platform restrictions on the activities of business
users in other transaction venues.
In the 117th Congress, the reported House version of the AICOA would have prohibited covered
platform operators from restricting a business user’s pricing of its products or services or its
communications on a covered platform regarding other transaction options.586
The DCPCA contains a similar prohibition. The bill would make it presumptively unlawful for a
covered platform to interfere with or restrict a business user’s pricing of its products or services,
whether or not those products or services are offered on the platform.587
Some of the pricing restrictions targeted by these bills include most-favored-nation clauses
(MFNs), which prohibit a platform’s business users from offering lower prices on rival
platforms.588 Platform MFNs may make it difficult for rivals to compete with a dominant platform

580 See supra “Amazon.”
581 See supra “Apple.”
582 S. 2033 § 3(a)(6).
583 S. 2710 § 3(c); H.R. 7030 § 3(c); H.R. 5017 § 3(c).
584 Francis, supra note 63, at 832; Hovenkamp, Platform Monopoly, supra note 367, at 2015; D. Daniel Sokol, A
Framework for Digital Platform Regulation, 17 COMPETITION L. INT’L 95, 102 (2021).
585 Andre Hagiu, Tat-How Teh & Julian Wright, Should Platforms Be Allowed to Sell on Their Own Marketplaces?, 53
RAND. J. ECON. 297, 32 (2022).
586 American Innovation and Choice Online Act, H.R. 3816, 117th Cong. § 2(b)(6), (b)(8) (2021) (Reported Version).
587 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2311(a)(5)(C), (c)(3) (2023). The
DCPCA would impose this prohibition by defining the term “self-preferencing” to include the specified type of
interference and by making “self-preferencing” presumptively unlawful. Id.
588 Jonathan B. Baker & Fiona Scott Morton, Antitrust Enforcement Against Platform MFNs, 127 YALE L.J. 2176, 2181
(2018). As discussed, Amazon has faced lawsuits challenging its pricing restrictions, though the nature of the relevant
policies has been disputed. See supra “Amazon.”
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by charging lower commissions, because such clauses prevent business users from passing along
those savings to consumers.589
The primary procompetitive benefit proffered in defense of MFNs involves concerns about
free-riding. The basic worry is that, absent an MFN, consumers will use a highly functional
platform to search for and compare products, but then make their purchases on a different
low-cost platform.590 Under those conditions, platforms may lack incentives to invest in
expensive site features like an attractive design or effective comparison tools, even though those
features benefit consumers.591
The literature has distinguished between “narrow” platform MFNs (which restrict a seller’s prices
only on the seller’s own website) and “wide” platform MFNs (which restrict a seller’s prices on
all other platforms).592 Some theoretical analyses have concluded that narrow MFNs are more
likely to be procompetitive than wide MFNs.593
Both narrow and wide platform MFNs would fall within the scope of the DCPCA and the
reported House version of the AICOA in the 117th Congress. Under the relevant version of the
AICOA, challenged restrictions would have escaped liability if a platform operator established by
clear and convincing evidence that its conduct would (1) not harm “the competitive process by
restricting or impeding legitimate activity by business users,” or (2) increase “consumer
welfare.”594 Under the DCPCA, by contrast, covered platforms would need to show by clear and
convincing evidence that their conduct “did not result in any harm to the relevant aggrieved
party.”595
App Preinstallation
The AICOA also includes a provision prohibiting covered firms from restricting or impeding the
uninstallation of preinstalled apps, unless such conduct is necessary for the security or
functioning of the platform or to prevent data from being transferred to a foreign adversary.596
The OAMA contained a similar prohibition.597
These prohibitions appear to be directed at concerns that Google and Apple have leveraged
control of their mobile operating systems to favor their own apps and app stores.598 Though the
bills do not explicitly prohibit the preinstallation of a covered firm’s proprietary apps,
commentators have debated whether such preinstallation would run afoul of the AICOA’s general
self-preferencing prohibition.599

589 Baker & Scott Morton, supra note 588, at 2195 n.82.
590 Id. at 2183-84.
591 Id. at 2184.
592 Schnitzer, et al., supra note 519, at 18 n.12.
593 Baker & Scott Morton, supra note 588, at 2184 n.23 (citing examples).
594 American Innovation and Choice Online Act, H.R. 3816, 117th Cong. §§ 2(c)(1), (c)(3) (2021) (Reported Version).
595 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2311(d) (2023).
596 American Innovation and Choice Online Act, S. 2033, 118th Cong. § 3(a)(8) (2023).
597 Open App Markets Act, S. 2710, 117th Cong. § 3(d)(3) (2022) (Reported Version); Open App Markets Act, H.R.
7030, 117th Cong. § 3(d)(3) (2021); Open App Markets Act, H.R. 5017, 117th Cong. § 3(d)(3) (2021).
598 See supra “Google” & “Apple.”
599 Compare Randy Picker, How Would the Big Tech Self-Preferencing Bill Affect Users?, PROMARKET (June 16,
2022), https://www.promarket.org/2022/06/16/how-would-the-big-tech-self-preferencing-bill-affect-users (arguing that
the AICOA’s self-preferencing prohibition may prohibit app preinstallation), with Hal Singer, Rep. Cicilline’s
(continued...)
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Structural Separation and Line-of-Business Restrictions
Several of the proposals discussed above respond to concerns that Big Tech firms face conflicts of
interest when they operate both a digital platform and vertically related businesses that compete
with platform users. The proposals seek to address those concerns by prohibiting specific
categories of allegedly problematic conduct. One possible downside of this approach involves
enforcement costs.
The worry is twofold. First, conduct rules require regulators to continuously monitor the behavior
of covered firms.600 Second, the availability of affirmative defenses means that rule enforcement
may entail some of the same issues of cost and timeliness that have led to dissatisfaction with the
existing antitrust framework.601
Based on these potential difficulties, some commentators have argued that structural restrictions
have important advantages over behavioral rules.602 Such restrictions can take two general forms.
Structural regulation could involve total separation, meaning firms would be prohibited from
owning both a covered platform and a business that operates on that platform.603 Alternatively,
regulations could mandate partial or functional separation, whereby firms would be required to
house a covered platform and vertically related businesses in separate legal entities.604
There is precedent for these types of structural regulations, including in the railroad, banking, and
telecommunications industries.605
The DCPCA would impose a separation requirement on certain tech platforms. The legislation
would make it unlawful for a covered platform operator to “maintain, or engage in any action that
creates, a platform conflict of interest.”606 It would empower a newly created agency to order
divestitures and other necessary remedies to eliminate prohibited conflicts of interest.607 The new
agency would also have the authority to engage in rulemaking to implement this prohibition.608
In the 117th Congress, H.R. 3825, the Ending Platform Monopolies Act, contained a more
detailed separation requirement.609 The bill would have prohibited covered platform operators
from owning, controlling, or having a beneficial interest in a “line of business” that
• utilizes the covered platform for the sale or provision of products or services;
• offers a product or service that the covered platform requires business users to
purchase or utilize as a condition of accessing or receiving preferred placement
on the platform; or

Nondiscrimination Bill Would Offer a Lifeline to Independent App Developers, PROMARKET (July 2, 2021),
https://www.promarket.org/2021/07/02/antitrust-self-preferencing-preinstallation-app-developers-apple/ (arguing that
the AICOA would not prohibit app preinstallation).
600 HJC REPORT, supra note 11, at 381; Khan, Platforms and Commerce, supra note 362, at 1036.
601 See, e.g., Francis, supra note 63, at 823-24.
602 HJC REPORT, supra note 11, at 381; Khan, Platforms and Commerce, supra note 362, at 1036; see also Rory Van
Loo, In Defense of Breakups: Administering a “Radical” Remedy, 105 CORNELL L. REV. 1955, 2007 (2020) (arguing
that breakups may be preferable to access remedies in certain circumstances).
603 Khan, Platforms and Commerce, supra note 362, at 1052.
604 Id.
605 Id. at 1037-43, 1045-51.
606 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2312(a) (2023).
607 Id. § 2312(b).
608 Id. § 2312(c).
609 Ending Platform Monopolies Act, H.R. 3825, 117th Cong. (2021).
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• gives rise to a “conflict of interest.”610
The bill would have provided that “conflicts of interest” arise when a platform operator’s
ownership or control of another “line of business” creates the incentive and ability for its platform
to (1) advantage the platform operator’s products or services over those of competitors, or
(2) exclude or disadvantage the products or services of competitors.611
These types of proposals have generated debate. Critics of separation requirements have argued
that a platform’s entry into new markets typically benefits consumers.612 For example, by selling
its own private-label products on its marketplace, Amazon may offer consumers low-cost
alternatives to established brands.613 Integration into related business lines may also create
efficiencies.614 Apple and Google, for instance, may be well-positioned to produce apps and app
stores for their respective operating systems, as well as related devices like earphones and smart
watches.615
Separation requirements may also face line-drawing difficulties. The boundary between a covered
platform and separate services is not always clear.616 For example, Apple produces many apps and
functionalities—including a voice assistant (Siri), a camera app, and a payment system (Apple
Pay)—that are integrated with its iOS operating system to various degrees.617 Whether these
services would qualify as “lines of business” that are distinct from iOS may be uncertain; H.R.
3825 did not define that term. Because tech platforms regularly add new functionalities to their
primary services, some observers have argued that an absence of clarity surrounding permissible
activities may deter innovation and thereby harm consumers.618
Proponents of separation requirements have acknowledged these criticisms. In response, they
have argued that the innovation benefits of an equal playing field would likely outweigh any
losses in static efficiency that result from the elimination of a platform operator’s downward
pricing pressure in adjacent markets.619 In addition, advocates of separation rules contend that any

610 Id. § 2(a).
611 Id. § 2(b).
612 Hagiu, et al., supra note 585, at 319; Herbert J. Hovenkamp, The Looming Crisis in Antitrust Economics, 101 B.U.
L. REV. 489, 541 (2021) [hereinafter “Hovenkamp, Looming Crisis”]; Giuseppe Colangelo, Evaluating the Case for
Regulation of Digital Platforms, in GLOBAL ANTITRUST INSTITUTE REPORT ON THE DIGITAL ECONOMY (2020); Thomas
A. Lambert, The Case Against Legislative Reform of U.S. Antitrust Doctrine 21-22 (Univ. of Mo. Sch. of L. Legal
Studies, Research Paper No. 2020-13, 2020), https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3598601; Todd,
supra note 319, at 524-25.
613 Hovenkamp, Looming Crisis, supra note 612, at 541 (“Many of the brands that compete with Amazon’s own brands
are sold by large firms, often at margins that are significantly higher than Amazon’s margins. . . . Forcibly separating
Amazon’s brands from the offerings of these companies will almost certainly reduce downward pricing pressure on
these national name brands, resulting in higher prices for consumers.”).
614 See, e.g., Todd, supra note 319, at 514-17.
615 Randy Picker, The House’s Recent Spate of Antitrust Bills Would Change Big Tech as We Know It, PROMARKET
(June 29, 2021), https://www.promarket.org/2021/06/29/house-antitrust-bills-big-tech-apple-preinstallation/.
616 Carl Shapiro, Protecting Competition in the American Economy: Merger Control, Tech Titans, Labor Markets, 33 J.
ECON. PERSPS. 69, 84 (2019); Hal Singer, Inside Tech’s “Kill Zone”: How to Deal With the Threat to Edge Innovation
Posed by Multi-Sided Platforms, PROMARKET (Nov. 21, 2018), https://www.promarket.org/2018/11/21/inside-tech-kill-
zone/.
617 Todd, supra note 319, at 536.
618 E.g., Rogerson & Shelanski, supra note 421, at 1934.
619 Khan, Platforms and Commerce, supra note 362, at 1085; see also Feng Zhu & Qihong Liu, Competing with
Complementors: An Empirical Look at Amazon.com, 39 STRATEGIC MGMT. J. 2168 (2018) (concluding that, while
Amazon’s entry into a new market typically reduces prices, it may also reduce the number of innovative products on
Amazon’s marketplace by discouraging participation by third-party sellers).
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decreases in platform innovation caused by such rules must be weighed against likely increases in
innovation by platform users.620
Mergers & Acquisitions
Substantive Merger Law
Other proposals target mergers involving large tech platforms. The DCPCA would create a new
agency charged with reviewing certain mergers that involve covered platform operators.621 For
transactions subject to the HSR Act’s pre-merger filing requirement, the bill would require
covered platform operators to submit their filings to the new agency, in addition to the antitrust
agencies. To proceed with such transactions, covered platform operators would need to prove by
clear and convincing evidence that the transactions would “serve the public interest.”622
The bill lists 13 factors that are relevant to this inquiry, including a transaction’s effects on
competition, national security, privacy, and local communities.623 It also identifies certain fact
patterns in which a covered transaction “would not” serve the public interest, in addition to fact
patterns that “may” support a determination that a transaction would not serve the public interest.
The bill prescribes that a covered transaction “would not” serve the public interest if
• the acquired firm offers services or products that overlap or compete with, or that
are functionally equivalent to, those offered by the covered platform operator;
• the acquired firm is a “critical trading partner in the supply chains or business
ecosystems of the parties”; or
• the transaction would create a “platform conflict of interest.”624
The legislation identifies the following facts that “may” support a determination that a covered
transaction would not serve the public interest:
• the transaction would result in a post-transaction market share of greater than
33% in any relevant market (including labor markets);
• the transaction would (1) result in a Herfindahl-Hirschman Index (HHI) greater
than 1,800 in any relevant market, and (2) increase the HHI by more than 100;625
or

620 Khan, Platforms and Commerce, supra note 362, at 1085.
621 Digital Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2313 (2023).
622 Id. § 2313(b)(1).
623 Id. § 2313(d)(1).
624 Id. § 2313(d)(2).
625 As discussed, the HHI is a measure of market concentration calculated by summing the squares of each firm’s
market share. Thus, a market with four firms that each occupy 25% of the market would have an HHI of 2,500 (252 +
252 + 252 + 252). A market with an HHI of 1,800 qualifies as “moderately concentrated” under the 2010 Horizontal
Merger Guidelines, which indicate that mergers in such markets “potentially raise significant competitive concerns and
often warrant scrutiny” when they increase the market’s HHI by more than 100 points. HORIZONTAL MERGER
GUIDELINES, supra note 49, at § 5.3. Under the 1992 Merger Guidelines, a market with an HHI above 1,800 would have
qualified as “highly concentrated,” and the antitrust agencies adopted a rebuttable presumption of illegality for mergers
that increased the HHI of such markets by more than 100 points. DEP’T OF JUSTICE AND FED. TRADE COMM’N, 1992
MERGER GUIDELINES § 1.5 (1992).
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• the transaction would result in an aggregation of data or access to data that
“harms the competitive process or creates or helps maintain a monopoly, a
monopsony, market power, or unfair methods of competition.”626
In addition to requiring covered platform operators to prove by clear and convincing evidence
that HSR-reportable mergers would serve the public interest, the DCPCA would empower the
newly created platform regulator to block non-reportable transactions involving covered platform
operators upon a determination that they would not serve the public interest.627
The DCPCA would also give the new regulator the authority to review consummated mergers
involving covered platform operators and unwind those transactions upon a determination that
they “materially harmed the public interest.”628 The bill would allow the regulator to evaluate
whether a consummated transaction “materially harmed the public interest” by evaluating the
factors identified above, while also providing that such harm is present if
• the covered platform operator acquired a “critical trading partner”;
• the transaction resulted in a post-transaction market share of greater than 50% in
any relevant market (including labor markets); or
• the transaction (1) resulted in an HHI greater than 2,500 in any relevant market,
and (2) increased the HHI by more than 200.629
The DCPCA thus envisions a broad overhaul of the legal regime governing mergers involving
dominant platforms. In place of the existing framework in which courts inquire primarily into a
transaction’s economic effects, the bill would adopt per se rules against platform mergers that fall
into certain categories and empower a new specialist regulator to block platform mergers under a
public-interest standard.
Legislation in the 117th Congress likewise would have adopted certain per se rules for mergers
involving dominant platforms, but would not have established a public-interest standard for those
mergers or created a new regulator. H.R. 3826, the Platform Competition and Opportunity Act,
would have prohibited covered platform operators from acquiring other firms unless they could
demonstrate by clear and convincing evidence that a target does not
• compete with the platform operator;
• constitute “nascent or potential competition” for the platform operator;
• enhance or increase the platform operator’s market position with respect to
products or services offered on or directly related to a covered platform; or
• enhance or increase the platform operator’s ability to maintain its market position
with respect to products or services offered on or directly related to a covered
platform.630

626 S. 2597 § 2313(d)(3).
627 Id. § 2313(e).
628 Id. § 2314(a)-(b).
629 Id. § 2314(c).
630 Platform Competition and Opportunity Act of 2021, H.R. 3826, 117th Cong. § 2(b)(2) (2021). The bill would have
excluded certain categories of transactions that are exempt from pre-merger filing requirements for reasons other than
their size. Id. § 2(b)(1).
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The reported version of the bill included an amendment that would have exempted transactions of
less than $50 million from the prohibition.631
For transactions of $50 million or greater, then, the bill would have prohibited covered platforms
from engaging in horizontal mergers; mergers involving “nascent or potential” competitors; and
vertical and conglomerate mergers that enhance, increase, or help maintain their market positions
with respect to products or services “offered on or directly related” to a covered platform.
As drafted, the bill raised three issues. The first involved the legislation’s prohibition of
acquisitions involving “potential” competitors.632 As discussed, antitrust doctrine has recognized
two theories of harm in potential-competition cases: the elimination of perceived potential
competition and the elimination of actual potential competition.633 Courts have identified
prerequisites for both theories.634
The relationship between those prerequisites and H.R. 3826’s requirement that a covered platform
show that a target firm is not a “potential” competitor may have generated complex legal
questions if the bill had become law. For example, the bill could have been read to allow platform
operators to make such a showing by negating an element of both types of potential-competition
claims.635 However, that is not the only interpretive option; the details surrounding the relevant
burden would have had to be fleshed out in practice. That the Supreme Court has recognized only
the perceived-potential-competition theory might have complicated this inquiry.
The second issue concerned the bill’s prohibition of Big Tech acquisitions involving “nascent”
competitors.636 Commentators have offered different definitions of the concept of nascent
competition.637 In general, however, the term has been used to refer to firms and technologies
with uncertain prospects that nevertheless pose serious threats to an incumbent.638
Despite posing such threats, acquisitions of nascent competitors may be difficult to challenge
under existing law. As discussed, to prevail under an actual-potential-competition theory, a
plaintiff must establish a “substantial likelihood” that a target firm would deconcentrate the
relevant market or produce other procompetitive benefits.639 In cases involving unproven or

631 Amendment to the Amendment in the Nature of a Substitute to H.R. 3826 Offered by Ms. Ross of North Carolina,
Markups, H.R. 3843, the Merger Filing Fee Modernization Act of 2021, et al., H. Comm. on the Judiciary, 117th Cong.
(June 24, 2021), https://docs.house.gov/meetings/JU/JU00/20210623/112818/BILLS-117-HR3826-R000305-Amdt-
1.pdf.
632 H.R. 3826 § 2(b)(2)(B).
633 See supra “Mergers & Acquisitions.”
634 See id.
635 Under the bill, such efforts would be subject to a clear-and-convincing-evidence standard. H.R. 3826 § 2(b).
636 Id. § 2(b)(2)(B).
637 Yun, supra note 416, at 626 (“Amongst antitrust practitioners and scholars, various definitions have emerged for
nascent competition”); Hemphill & Wu, supra note 416, at 1881 (“Nascent competition means different things to
different people.”).
638 United States v. Microsoft Corp., 253 F.3d 34, 79 (D.C. Cir. 2001) (per curiam); Yun, supra note 416, at 626-27;
Hemphill & Wu, supra note 416, at 1886-88; Tracy J. Penfield & Molly Pallman, Looking Ahead: Nascent Competitor
Acquisition Challenges in the “TechLash” Era, ANTITRUST SOURCE 2 (June 2020),
https://www.americanbar.org/content/dam/aba/publishing/antitrust-magazine-online/2020/june-
2020/jun20_penfield_6_17f.pdf.
639 United States v. Marine Bancorporation, Inc., 418 U.S. 602, 633 (1974).
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developing technology, that burden could prove problematic for a plaintiff. H.R. 3826 was a
response to this doctrinal difficulty.640
While the bill thus sought to address an issue that has generated considerable attention, the
analytical framework that would govern inquiries into nascent competition remains unsettled.
There is little case law addressing issues of nascent competition in the merger context.641
Accordingly, H.R. 3826 would have leaned on the courts to develop standards for evaluating
whether a firm constituted a nascent competitor of a covered platform.
The third issue raised by H.R. 3826 involved the breadth of the provisions prohibiting mergers
that “enhance or increase” a platform operator’s market position or ability to maintain its market
position.642
By their terms, these prohibitions did not distinguish between procompetitive mergers and
anticompetitive mergers. As drafted, the bill thus appeared to prohibit mergers that “enhance or
increase” a covered platform’s market position by improving the quality of its products or
services, even when the target company is not a competitor, potential competitor, or nascent
competitor of the platform. As a result, H.R. 3826 may have limited Big Tech platforms to
in-house development or licensing of complementary technologies; acquisitions of firms that
could enhance a platform’s core offerings would have likely been off-limits.
S. 1074—another bill in the 117th Congress—would have taken a similarly strict approach
toward Big Tech mergers.643 Among other things, S. 1074 would have prohibited companies
designated as “dominant digital firms” from engaging in acquisitions valued at more than
$1 million.644
Other proposals are more limited. Several commentators, for example, have advocated a
requirement that Big Tech firms bear the burden of proving that their mergers would not harm
competition.645
Abstracting from specific policy options, the debate over special merger rules for Big Tech firms
has focused on two general concerns.

640 There is an ongoing debate as to whether Section 2 of the Sherman Act provides a more attractive vehicle for
challenging acquisitions of nascent competitors than Section 7 of the Clayton Act. Compare Hemphill & Wu, supra
note 416, at 1896-1901 (discussing the advantages of Section 2); Melamed, supra note 416, at 6-7 (similar), with Scott
Sher, Keith Klovers & John Ceccio, Nascent Competition, Section 2, and the Agencies’ Quixotic Quest to Avoid the
Potential Competition Doctrine, ANTITRUST MAGAZINE ONLINE (Aug. 2021),
https://www.americanbar.org/content/dam/aba/publishing/antitrust-magazine-online/august-2021/atonline-sher.pdf
(arguing that Section 2 is less stringent than Section 7 as applied to mergers); Jonathan Jacobson & Christopher
Mufarrige, Acquisitions of “Nascent” Competitors, ANTITRUST SOURCE 5-6 (Aug. 2020),
https://www.americanbar.org/content/dam/aba/publishing/antitrust-magazine-online/2020/august-
2020/aug20_full_source.pdf (similar). Both approaches remain largely untested.
641 See, e.g., Yun, supra note 416, at 635 (“A considerable downside to bringing a nascent competition case under
[Section] 7 is that there are no court precedents for doing so. . . . Consequently, a court would need to develop new
conditions and requirements to find a violation, which is certainly a major impediment to applying the nascent
competition doctrine in [Section] 7 cases.”).
642 Platform Competition and Opportunity Act of 2021, H.R. 3826, 117th Cong. § 2(b)(2)(C)-(D) (2021).
643 Trust-Busting for the Twenty-First Century Act, S. 1074, 117th Cong. § 4 (2021).
644 Id.
645 STIGLER REPORT, supra note 415, at 98, 111; ACCC Report, supra note 218, at 109; see also OECD STARTUP
ACQUISITION REPORT, supra note 416, at 38-41 (cataloguing various rebuttable-presumption proposals).
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First, opponents of such rules have argued that Big Tech mergers are typically benign or
procompetitive.646 Acquisitions of complementary technologies, for example, may reduce the
transaction costs associated with licensing arrangements or allow for more efficient integration
with a platform’s offerings.647 Mergers may also stimulate competition among Big Tech firms by
giving them an attractive means of entering or expanding within each other’s core markets.648
Second, some have argued that limitations on Big Tech mergers may reduce startup investment by
eliminating a popular exit route for venture investors and other entrepreneurs.649
Proponents of special merger rules for tech platforms have responded that the procompetitive
benefits of tech mergers are often overstated.650 Merger limitations targeting a handful of
prospective acquirers may also leave startup investors with enough viable exit options to mitigate
concerns about dampened investment. Additionally, some commentators have suggested that
reducing investment in innovations that end up in the hands of dominant incumbents is the
intended outcome of the relevant proposals.651
The Merger Review Process
Before moving on from mergers, one final topic warrants mention: the HSR pre-merger review
process. As discussed, under the HSR Act, parties to mergers that exceed certain thresholds must
report their transactions to the DOJ and FTC and abide by specified waiting periods before
closing.652 This process gives the agencies the opportunity to review proposed mergers for
antitrust concerns and seek relief before deals are consummated.
Some commentators have expressed concerns about the number of Big Tech mergers that fall
below the relevant thresholds and thus avoid HSR review.653 In September 2021, the FTC
released a report indicating that the four Big Tech firms discussed in this report and Microsoft
together engaged in 819 non-reportable deals between 2010 and 2019.654

646 Samuel Bowman & Sam Dumitriu, Better Together: The Procompetitive Effects of Mergers in Tech, INT’L CTR. FOR
L. & ECON. (Oct. 1, 2021), https://laweconcenter.org/resources/better-together-the-procompetitive-effects-of-mergers-
in-tech/?doing_wp_cron=1676398306.5821518898010253906250; UK DIGITAL COMPETITION REPORT, supra note 415,
at 101 (concluding that regulators should adopt a “balance of harms” approach to platform mergers instead of a
presumption of illegality because “the majority of acquisitions by large digital companies are likely to be either benign
or beneficial for consumers”).
647 Bowman & Dumitriu, supra note 646; A. Douglas Melamed & Nicolas Petit, The Misguided Assault on the
Consumer Welfare Standard in the Age of Platform Markets, 54 REV. OF INDUS. ORG. 741, 754 (2019).
648 Bowman & Dumitriu, supra note 646.
649 Gary Dushnitsky & D. Daniel Sokol, Mergers, Antitrust, and the Interplay of Entrepreneurial Activity and the
Investments That Fund It, 24 VAND. J. OF ENT. & TECH. L. 255 (2022); Jacobson & Mufarrige, supra note 640, at 10;
UK DIGITAL COMPETITION REPORT, supra note 415, at 101.
650 John M. Newman, Antitrust in Digital Markets, 72 VAND. L. REV. 1497, 1541 (2019).
651 Hemphill & Wu, supra note 416, at 1893.
652 15 U.S.C. § 18a. As discussed, the DCPCA would require covered platform operators to also submit HSR-reportable
deals to a newly created regulator and allow that regulator to block such deals under a public-interest standard. Digital
Consumer Protection Commission Act of 2023, S. 2597, 118th Cong. § 2313(a)-(c) (2023).
653 STIGLER REPORT, supra note 415, at 111.
654 FTC NON-REPORTABLE ACQUISITIONS STUDY, supra note 414, at 10.
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In response to worries about these transactions, some have supported a blanket HSR filing
requirement for acquisitions by dominant tech platforms.655 Opponents of such a rule have argued
that it would be burdensome and offer few benefits for regulators.656
Interoperability & Data Portability
Network effects and switching costs are frequent themes in discussions of Big Tech.657 Some
reform proposals seek to address these structural features of certain platform markets by imposing
interoperability and data-portability obligations on designated-platform operators.658
Interoperability refers to the ability of distinct services to work together and communicate with
one another.659 Interoperability can develop organically—as with email—or as a result of a legal
mandate.660 Examples in the latter category include the 1996 Telecommunications Act’s
requirement that local exchange carriers interconnect with other providers.661 The DOJ’s 2002
monopolization settlement with Microsoft also included an interoperability provision prohibiting
Microsoft from excluding other firms’ web browsers from its Windows operating system.662
These types of measures seek to lower the entry barriers associated with networked industries by
shifting network effects from individual firms to the market as a whole, making them available to
nascent and potential competitors of a dominant incumbent.663
Data portability, by contrast, refers to a consumer’s right to move his or her data from one
platform to another.664 Telecommunications law again offers an example by granting phone users
the right to retain their phone numbers when they change carriers.665 Such requirements decrease
the switching costs that might otherwise discourage consumers from taking their business to a
more attractive provider.666
In the 117th Congress, H.R. 3849 would have imposed interoperability and data-portability duties
on designated digital platforms.667 The bill would have directed the FTC to develop standards

655 HJC REPORT, supra note 11, at 388.
656 ABA DIGITAL ECONOMY REPORT, supra note 438, at 16.
657 See, e.g., HJC REPORT, supra note 11, at 40-42; STIGLER REPORT, supra note 415, at 38-39, 109; UK DIGITAL
COMPETITION REPORT, supra note 415, at 35-36.
658 OECD, DATA PORTABILITY, INTEROPERABILITY AND DIGITAL PLATFORM COMPETITION (2021),
https://www.oecd.org/daf/competition/data-portability-interoperability-and-digital-platform-competition-2021.pdf
[hereinafter “OECD INTEROPERABILITY REPORT”]; HJC REPORT, supra note 11, at 384-86; STIGLER REPORT, supra note
415, at 109-10, 113; see also Kades & Scott Morton, supra note 424 (advocating interoperability remedies in antitrust
litigation involving tech platforms).
659 Ezrielev & Marquez, supra note 223, at 9; OECD INTEROPERABILITY REPORT, supra note 658, at 12.
660 Herbert Hovenkamp, Antitrust Interoperability Remedies, 123 COLUM. L. REV. F. 1, 10 (2023) [hereinafter
“Hovenkamp, Interoperability Remedies”].
661 47 U.S.C. § 251(c).
662 United States v. Microsoft Corp., 215 F. Supp. 2d 1 (D.D.C. 2002). For other examples of antitrust cases in which
interoperability has been used as a remedy, see Hovenkamp, Interoperability Remedies, supra note 660, at 13 n.74.
663 Kades & Scott Morton, supra note 424, at 41-42; Becky Chao & Ross Schulman, Promoting Platform
Interoperability, NEW AM. FDN. 21-22 (May 2020).
664 Michal S. Gal & Daniel L. Rubinfeld, Data Standardization, 94 NYU L. REV. 737, 739 (2019).
665 47 U.S.C. § 251(b)(2).
666 Juan Pablo Maicas, et al., Reducing the Level of Switching Costs in Mobile Communications: The Case of Mobile
Number Portability, 33 TELECOMMS. POL’Y 544 (2009).
667 ACCESS Act of 2021, H.R. 3849, 117th Cong. §§ 3-4 (2021).
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implementing those duties for individual covered platforms.668 In promulgating standards under
the legislation, the FTC would have been advised by technical committees that included
representatives of a platform’s competitors, competition and privacy-advocacy organizations, the
National Institute of Standards and Technology, and covered platforms.669
The obligations contemplated by H.R. 3849 were potentially broader than those in the AICOA,
which were discussed earlier in this report.670 The AICOA’s interoperability provision would
prohibit a covered platform operator from restricting the ability of business users to interoperate
with features that are available to the operator’s own products or services.671 Accordingly, the
prohibition would have been limited to a platform operator’s unequal treatment of firms that
utilize its platform.672
In contrast, H.R. 3849 would have granted the FTC rulemaking authority to impose potentially
broader, platform-specific interoperability obligations.673 For a social network like Facebook, an
interoperability rule might have included duties to allow users of other networks to “friend”
Facebook users and transmit posted content from Facebook to other networks.674 Supporters of
interoperability have argued that these types of obligations would catalyze competition by
allowing users of upstart social networks to benefit from Facebook’s scale.675
H.R. 3849’s data-portability provision was also potentially broader than the parallel requirement
in the AICOA. While the AICOA’s requirement would apply only to a platform’s business
users,676 H.R. 3849’s data-portability obligation would have encompassed individuals who use a
covered platform.677
A rule implementing this duty might have required a social network like Facebook to keep a
user’s messages, photos, and other content in an accessible format that could be transferred to
other platforms.678 Although this type of requirement may have partially overlapped with the
ongoing transferability contemplated by H.R. 3849’s interoperability mandate, it could also have
included categories of data not subject to continuous real-time interoperability for technical or
other reasons.679 Data-portability rules may likewise require Amazon to allow retailers on its

668 Id. § 6(c).
669 Id. § 7.
670 See supra “Interoperability and Data Access.”
671 American Innovation and Choice Online Act, S. 2033, 118th Cong. § 3(a)(4) (2023).
672 The reported House version of the AICOA in the 117th Congress also included a broader provision that prohibited
covered platform operators from restricting a business user’s ability to interoperate with “any product or service.” H.R.
3816 § 2(b)(9).
673 ACCESS Act of 2021, H.R. 3849, 117th Cong. §§ 4, 6 (2021); see also Schnitzer, et al., supra note 519, at 22
(contrasting the AICOA’s interoperability provision with the “general interoperability requirement” in H.R. 3849).
674 Kades & Scott Morton, supra note 424, at 16; Transcript of Markup of H.R. 3843, the Merger Filing Fee
Modernization Act, et al., at 48,832-48,835 (June 23, 2021) (on file with author) [hereinafter “H.R. 3849 Markup
Transcript”] (Rep. Mary Gay Scanlon) (“Much like texting allows iPhone owners to communicate with Android
owners, so, too, would [H.R. 3849] allow individuals switching to new social media platforms to be able to
communicate and interact with their friends and family on Facebook.”).
675 Kades & Scott Morton, supra note 424, at 9.
676 S. 2033 § 3(a)(4).
677 H.R. 3849 § 3.
678 Hovenkamp, Interoperability Remedies, supra note 660, at 27.
679 See id. (arguing that “dynamic” interoperability for social networks might be technically difficult and that the
“static” interoperability offered by data portability may thus be a more promising option).
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marketplace to port their customer reviews to rival e-commerce platforms and Apple to permit
iPhone users to transfer their message histories to an Android device.680
Objections to interoperability and data-portability mandates take several forms. Some have
highlighted the complexity of interoperability requirements, which may pose challenges of
implementation and enforcement.681 Others have focused on possible privacy and data-security
risks that might accompany both interoperability and data-portability rules.682
H.R. 3849 attempted to address complexity concerns by directing the FTC to establish technical
committees to assist with rule development.683 The bill sought to mitigate privacy and
data-security risks by imposing data-security requirements on firms that interoperate with or
receive ported data from a covered platform.684
Another category of criticism directed at interoperability requirements involves innovation
concerns. Some have worried that interoperability may result in homogenized markets as an
incumbent’s rivals coalesce around a single set of standards.685 Compelled interoperability also
potentially implicates the free-rider problems that motivate narrow duty-to-deal doctrine: by
requiring firms to share the fruits of their innovation with competitors, policymakers may dampen
incentives to invest in new products.686 Defenders of interoperability have acknowledged this
risk, but maintain that interoperating Big Tech platforms would still face incentives to innovate to
prevent rivals from gaining a competitive edge.687
Changes to General Antitrust
While the proposals discussed above would entail special competition rules for large tech
platforms, other options involve changes to general antitrust law. Because general antitrust reform
is a vast topic, this report does not attempt an exhaustive overview of the relevant proposals.
Instead, it briefly reviews selected bills involving exclusionary conduct and merger law.
Exclusionary Conduct
S. 225, the Competition and Antitrust Law Enforcement Reform Act (117th
Cong.)
In the 117th Congress, S. 225 would have made several changes to the legal framework
governing exclusionary-conduct claims.688 The bill would have amended the Clayton Act to

680 H.R. 3849 Markup Transcript, supra note 674, at 4,564-4,568 (Rep. David Cicilline).
681 See, e.g., Hovenkamp, Interoperability Remedies, supra note 660, at 35; Randy Picker, Forcing Interoperability on
Tech Platforms Would Be Difficult to Do, PROMARKET (Mar. 11, 2021), https://www.promarket.org/2021/03/11/
interoperability-tech-platforms-1996-telecommunications-act/.
682 See, e.g., Laura Alexander & Randy Stutz, Interoperability in Antitrust Law & Competition Policy, COMPETITION
POLICY INT’L ANTITRUST CHRON. 31, 36 (June 2021); OECD INTEROPERABILITY REPORT, supra note 658, at 24; Peter
Swire & Yianni Lagos, Why the Right to Data Portability Likely Reduces Consumer Welfare: Antitrust and Privacy
Critique, 72 MD. L. REV. 335, 365-75 (2013).
683 ACCESS Act of 2021, H.R. 3849, 117th Cong. § 6 (2021).
684 Id. §§ 3(b), 4(b).
685 Hovenkamp, Interoperability Remedies, supra note 660, at 35; Ezrielev & Marquez, supra note 223, at 10-11.
686 See, e.g., FUMAGALLI, et al., supra note 73, at 547; ABA Letter, supra note 507, at 14; Ezrielev & Marquez, supra
note 223, at 10-11; Shelanski, supra note 95, at 371.
687 Kades & Scott Morton, supra note 424, at 26.
688 Competition and Antitrust Law Enforcement Reform Act of 2021, S. 225, 117th Cong. §§ 9, 13 (2021).
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prohibit “exclusionary conduct that presents an appreciable risk of harming competition.”689
“Exclusionary conduct” would have been defined to mean conduct that (1) “materially
disadvantages” an actual or potential competitor, or (2) “tends to foreclose or limit” the ability of
an actual or potential competitor to compete.690
S. 225 would have adopted a presumption that exclusionary conduct presents “an appreciable risk
of harming competition” if it is undertaken by a firm with a market share of greater than 50% or
that otherwise has “significant market power” in the relevant market.691 That presumption could
be rebutted, however, if a defendant established by a preponderance of the evidence that
1. “distinct procompetitive benefits of the exclusionary conduct in the relevant
market eliminate the risk of harming competition presented by the exclusionary
conduct”;
2. another firm has “entered or expanded their presence in the market with the effect
of eliminating the risk of harming competition posed by the exclusionary
conduct”; or
3. “the exclusionary conduct does not present an appreciable risk of harming
competition.”692
The bill would have provided that several of the conduct-specific tests that courts have adopted in
Sherman Act cases would not apply to exclusionary-conduct claims under the amended Clayton
Act. Among other things, exclusionary-conduct plaintiffs would not have to show
• that a defendant terminated a prior course of dealing,693 which some courts have
held is a prerequisite for refusal-to-deal liability under the Sherman Act;694
• that the defendant priced its products below its costs or is likely to recoup losses
from below-cost pricing,695 which are both requirements for predatory-pricing
claims under the Sherman Act;696 or
• that the conduct of a multi-sided platform presents an appreciable risk of harming
competition on more than one side of the platform,697 contrary to the rule the
Supreme Court adopted for two-sided transaction platforms in Ohio v. American
Express.698
S. 225 also would have provided that market definition is not necessary to prove an antitrust
violation, except in cases where the applicable statute includes the phrase “relevant market,”
“market concentration,” or “market share.”699

689 Id. § 9.
690 Id.
691 Id.
692 Id.
693 Id.
694 E.g., Novell, Inc. v. Microsoft Corp., 731 F.3d 1064, 1075 (10th Cir. 2013) (Gorsuch, J.).
695 Competition and Antitrust Law Enforcement Reform Act of 2021, S. 225, 117th Cong. § 9 (2021).
696 Brooke Grp. Ltd. v. Brown & Williamson Tobacco Corp., 509 U.S. 209, 222-24 (1993).
697 S. 225 § 9.
698 Ohio v. Am. Express Co., 138 S. Ct. 2274, 2286-87 (2018).
699 S. 225 § 13(a).
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S. 1074, the Trust-Busting for the Twenty-First Century Act (117th Cong.)
S. 1074—another bill in the 117th Congress—also would have made changes to the standards
governing exclusionary-conduct claims.700 The legislation would have provided that, in litigation
under Section 1 or Section 2 of the Sherman Act, a defendant that relies upon procompetitive
effects to justify its conduct must establish by clear and convincing evidence that
1. the relevant procompetitive effects “clearly outweigh” any anticompetitive
effects; and
2. the defendant “could not obtain substantially similar procompetitive effects
through commercially reasonable alternatives that would involve materially
lower competitive risks.”701
Like S. 225, the bill would have provided that market definition is not required to prove a
violation of Section 1 or Section 2.702
Mergers
S. 225, the Competition and Antitrust Law Enforcement Reform Act (117th
Cong.)
In addition to the exclusionary-conduct provisions discussed above, S. 225 would have modified
several aspects of merger law. The bill would have amended Section 7 of the Clayton Act to
prohibit mergers that “create an appreciable risk of materially lessening” competition703—a
change from the current language that prohibits mergers that may “substantially” lessen
competition.704 The term “materially” was defined to mean “more than a de minimis amount.”705
S. 225 also would have shifted the relevant burden of proof to the merging parties in certain
circumstances.706 For example, merging parties would have had the burden of proving that their
transactions would not “create an appreciable risk of materially lessening” competition in cases
where
• a merger would lead to a “significant increase in market concentration”;
• a firm with a market share greater than 50% or that possesses “significant market
power” acquires a competitor or a company that has a “reasonable probability” of
becoming a competitor;
• a transaction is valued at more than $5 billion; or
• the acquiring firm has assets, net revenue, or a market capitalization exceeding
$100 billion and the transaction is valued at $50 million or more.707

700 Trust-Busting for the Twenty-First Century Act, S. 1074, 117th Cong. § 2 (2021).
701 Id.
702 Id.
703 S. 225 § 4(b)(1).
704 15 U.S.C. § 18.
705 S. 225 § 4(b)(3).
706 Id.
707 Id.
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S. 1074, the Trust-Busting for the Twenty-First Century Act (117th Cong.)
S. 1074 also included merger restrictions.708 The bill would have prohibited firms with market
capitalizations exceeding $100 billion from engaging in mergers whose effect “may be to lessen
competition in any way.”709 It also would have explicitly provided that market definition is not
necessary to block a merger and that mergers shall not be presumed to be legal on the grounds
that the parties are not direct competitors.710
S. 3847, the Prohibiting Anticompetitive Mergers Act (117th Cong.)
In the 117th Congress, S. 3847 would have taken a similarly skeptical approach to large mergers.
The legislation would have prohibited mergers valued at more than $5 billion, mergers that result
in a market share of over 33% for sellers or 25% for employers, and mergers that would result in
specified levels of market concentration.711
S. 3847 also would have made changes to the merger-review process.712 Among other things, the
bill would have extended the initial HSR waiting period from 30 days to 120 days and allowed
the antitrust agencies to block mergers without obtaining a court order.713
In addition, the bill would have directed the DOJ and FTC to review mergers consummated after
January 1, 2000, if they would have qualified as “prohibited mergers” under the categories
mentioned above.714 It would have further required the agencies to pursue remedies to restore
competition or address the anticompetitive effects of those mergers in specified circumstances.715

Author Information

Jay B. Sykes

Legislative Attorney

708 S. 1074 contained both size-based merger restrictions and merger restrictions that would have applied to companies
designated as “dominant digital firms.” Trust-Busting for the Twenty-First Century Act, S. 1074, 117th Cong. §§ 3, 4
(2021). The latter are discussed in supra “Substantive Merger Law.”
709 S. 1074 § 3.
710 Id.
711 Prohibiting Anticompetitive Mergers Act of 2022, S. 3847, 117th Cong. § 3 (2022). The market-concentration
prohibition would have barred mergers that would (1) result in an HHI of greater than 1,800, and (2) increase the HHI
by more than 100 points. Id.
712 S. 3847 § 4(b).
713 Id.
714 Id. § 6.
715 Id.
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