The U.S. Justice Department has subpoenaed documents from Clayton Holdings LLC, once Wall Street’s largest mortgage due-diligence firm, as investigators eye-ball the due diligence that was performed on residential MBS deals in the run-up to the financial crisis. According to Bloomberg, the Justice Department presented a subpoena to Clayton on July 1, requesting an extensive amount of documentation having to do with the firm’s work on such deals. The DoJ is apparently seeking internal communications related to a review of pools of loans, due-diligence reviews performed by Clayton, as well as all communication between the clients for whom the company performed such reviews and the employees with which they dealt. The subpoena is...