Ohio v. American Express Co.

The Supreme Court issued a decision in a fight over whether American Express used anti-steering contract terms to block price competition among credit cards. The case asked how courts should apply the Sherman Act's "rule of reason" to a two-sided credit-card platform serving merchants and cardholders.

The case affects how hard it is for governments and businesses to challenge restrictions used by platform companies. For example, a store that wants to steer shoppers to a lower-fee card could face a tougher or easier antitrust test depending on the Court's approach.

The Supreme Court has finished this docket action. Lower courts, merchants, and antitrust enforcers now have to work with the decision in similar future cases.

The case asked whether proof that Amex's rules reduced merchant-side price competition was enough to show unlawful harm under antitrust law.

It affects whether stores can challenge card-network rules that limit steering customers to lower-fee cards. That can shape merchant costs and consumer prices.

The Supreme Court's work in this case is over. Lower courts and antitrust enforcers must apply the decision in future disputes involving similar platform rules.