Ohio and 10 others states — Connecticut, Idaho, Illinois, Iowa, Maryland, Michigan, Montana, Rhode Island, Utah and Vermont — brought the challenge, arguing the company’s rule violates federal antitrust laws by restricting trade.

The states claimed the rules had the actual market effect of raising the price of fees credit card companies charge merchants and that those increased costs have been passed on to the consumer.

American Express, however, argued its rules have allowed it to compete in a market where Visa and MasterCard command a combined share of 68 percent of credit card transactions.

Justice Clarence Thomas delivered the majority opinion, which Chief Justice John Roberts and Justices Anthony Kennedy, Samuel Alito and Neil Gorsuch joined.

Justice Stephen Breyer filed a dissenting opinion, which the other members of the court’s liberal wing — Justices Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan — joined.

Thomas said the court found the challengers’ argument that American Express agreements increase merchant fees unpersuasive.


Supreme Court sides with American Express in antitrust case