Much Ado About Amex

By Keith N. Hylton 
Ohio v. Amex has gained a great deal of attention because of its implications for digital platforms. The decision, though harshly criticized by many commentators, does not presage major changes in antitrust enforcement. Amex is likely to have a limited impact on antitrust law and enforcement. The reason Amex has a limited reach is that it is mostly a response to the plaintiffs’ proof of market power using direct (pricing) evidence. Amex should be understood as a statement about the direct evidence approach to proving or inferring market power. Under Amex, in cases involving two-sided markets where plaintiffs present such direct evidence, courts must conduct market power analyses with a view toward both sides of the market.