U.S. District Judge Paul Engelmayer of the Southern District of New York will allow to go forward a suit claiming a dozen of the biggest banks colluded against competition in the $230 trillion interest rate swap market.

The order, issued late last week, represented a partial victory for plaintiffs seeking class status in the consolidated suit In re: Interest Rate Swaps Antitrust Litigation, 16-md-02704, against major financial firms such as Bank of America, JPMorgan Chase & Co. and Citibank. The defendants filed a motion to dismiss antitrust claims, arguing among other things that the plaintiffs, which include institutional investors as well as third-party trading companies, failed to meet the antitrust collusion requirements.