SACRAMENTO — A federal judge on Thursday disqualified Winston & Strawn from additional work on the city of San Bernardino’s bankruptcy proceedings, ruling that the Chicago-based firm has an insurmountable conflict.

U.S. Bankruptcy Judge Meredith Jury in Riverside sided with the California Public Employees’ Retirement System, which accused Winston of hiring away K&L Gates attorneys who had worked on the bankruptcy case for CalPERS. Winston represents National Public Finance Guarantee Corp., a bond insurer and rival of CalPERS in the ongoing battle over San Bernardino’s assets.