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President and Founder

Geoffrey A. Manne is president and founder of the International Center for Law and Economics (ICLE), a nonprofit, nonpartisan research center based in Portland, Oregon. He is also a distinguished fellow at Northwestern University’s Center on Law, Business, and Economics. Previously he taught at Lewis & Clark Law School. Prior to teaching, Manne practiced antitrust law at Latham & Watkins, clerked for Hon. Morris S. Arnold on the 8th Circuit Court of Appeals, and worked as a research assistant for Judge Richard Posner. He was also once (very briefly) employed by the FTC. Manne holds AB & JD degrees from the University of Chicago.


Antitrust Platforms


In defence of the Supreme Court’s ‘single market’ definition in Ohio v American Express


The Supreme Court’s decision in Ohio, et al v Am Express Co, et al (‘Amex’)[1] is uniquely important for the antitrust analysis of firms in the modern platform economy. Although it is undoubtedly not the last word on the subject, the case represents the Court’s first comprehensive effort to address the thorny and previously indeterminate question of how courts should define the relevant market and assess competitive effects in antitrust cases involving two-sided or multi-sided platforms (‘two-sided markets’). In this article, I evaluate the Supreme Court’s approach to this question, discuss the economic and legal underpinnings of how it approached market definition and effects analysis, and demonstrate why the primary criticisms of the Court’s decision are misguided. While the Court’s approach has been roundly decried by some, its conclusion—that both sides of a two-sided market must be considered in defining the relevant market and evaluating the existence and consequences of a firm’s exercise of market power—is, indeed, the proper one.

[1] (2018) 138 S Ct 2274 (Slip Opinion) [hereinafter, ‘Amex’ and ‘Amex Slip Op.’].