The 2023 Merger Guidelines: Law, Fact, and Method

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"The final version of the 2023 Merger Guidelines, issued in December, 2023, is a vast improvement over an earlier draft, indicating that the Agencies took the many comments they received on a draft very seriously. These Guidelines break some new ground that older Guidelines did not address, and make many positive contributions, which this paper spells out. They are also excessively nostalgic for a past era, however, and this may explain their propensity to treat empirical questions as issues of law: that is one way to insulate them from further revision. The excessive reliance on one decision, Brown Shoe, is unfortunate, particularly since that decision has been so often repudiated, even by the Supreme Court itself. This paper pays particular attention to the Guidelines’ treatment of structural triggers and direct measures of competitive effects, its aggressive position on potential competition mergers, its willingness to weigh a “trend” toward concentration as a factor, and its treatment of serial acquisitions. It includes a welcome new section on mergers involving multi-sided networks, although its view of them is too one-sided, and it also contains an expanded section on mergers with harmful effects on suppliers, including labor. Its treatment of market definition is likely to lead to underenforcement because it defines markets too broadly. Finally, it could have made better use of recent retrospective studies, many of which would have provided further support for the substantive positions that it takes. "


mergers, antitrust, FTC, Justice Department, Clayton Act, Merger Guidelines

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Review of Industrial Organization