AmEx Must Answer Merchants’ Amended Swipe Fee Complaint

American Express Co. lost a round in a private antitrust action about its rules barring merchants from asking customers to use cards with cheaper swipe fees even though it won against antitrust enforcers in the U.S. Supreme Court on the same question.

AmEx must answer the merchants’ revised complaint, which was filed after the Supreme Court rendered an opinion in June that allows AmEx’s rules to stand for now, Judge Nicholas Garaufis of the U.S. District Court for the Eastern District of New York held Sept. 26.

AmEx filed a motion to dismiss the revised complaint, but Garaufis denied it, ...