It’s rare for a court to appoint its own expert in a class action. But Judge Gleeson of the Eastern District of New York is poised to do precisely that in order to help him decide whether to grant final approval to the $7.25 billion proposed class settlement of antitrust claims by retailers challenging Visa’s and MasterCard’s interchange fees. Some observers say that the proposed class settlement in the case—In re Payment Card Interchange Fee and Merchant Discount Antitrust Litigation, No. 1:05-md-01720—would be the largest class settlement of private antitrust claims in U.S. history.