Ohio v. Amex

In 2018, the U.S. Supreme Court handed down a decision in Ohio v. Amex that sent ripples through the antitrust world. In the highly anticipated opinion, Justice Clarence Thomas assessed how the relevant market should be defined in antitrust cases involving “two-sided markets.” What was monumental about the decision, and what are the potential far-reaching consequences? Julie Elmer, antitrust expert and former DOJ attorney, explains the crux of the decision, how some lower courts have interpreted the opinion since, and why some antitrust scholars and practitioners are concerned about its future impact.


Julie Elmer is a partner in the antitrust and litigation practices at Freshfields.

Additional Resources

Ohio v. American Express Co.   (read the full Supreme Court opinion from Oyez)

More from Julie Elmer

The Failing Firm Defense (in a Time of COVID-19 Bankruptcies)  (a TOL Brief)