Antitrust Has Forgotten its Coase

There is a raging debate within antitrust to determine how to best assess the conduct of digital platforms and tailor the enforcement of antitrust laws to the modern economy. The distinguishing features of digital platforms can make their analysis quite different from conventional, single-sided markets. The Supreme Court’s ruling in Ohio v. American Express (“Amex”) was the first decision to explicitly incorporate features of multisided platforms into antitrust analyses. However, the decision has divided academics and practitioners as to whether the Court properly incorporated platform features into antitrust’s rule of reason framework, which seeks to divide the burden of production between plaintiffs and defendants. Adding fuel to the fire are the lower courts’ interpretation of Amex, including in U.S. v. Sabre, where the district court ruled that only “transactional” platforms compete with other transactional platforms, which effectively short-circuited the competitive analysis. This Article argues that antitrust has forgotten the lessons from Ronald Coase’s work on the nature of the firm. Specifically, categorizing business organizations as “platforms” is insufficient to properly inform the actual competitive effects analysis. Firms organize in various ways to ultimately turn inputs into outputs. Precisely how this process is achieved is relevant to understand a firm’s conduct and incentives, but firm organization alone should not lead to competitive effects conclusions. In light of Coase, this Article reexamines the Court’s Amex decision to put suitable bounds on its precedential value. Additionally, this Article examines several key antitrust cases before and after Amex to assess their fidelity to a Coasian interpretation of platforms