On September 24, a firm that handles due-diligence matters for financial institutions filed its opposition to a motion filed by the U.S. Attorney’s Office for the District of Connecticut, on behalf of the federal-state RMBS Working Group, to compel production of documents and information the group sought in a July subpoena. In its brief, the firm reviews its cooperation to respond to “six years of subpoenas, investigatory demands, and formal and informal requests for information,” and summarizes the volume and types of information it has provided to the DOJ and the Working Group to date as a third-party witness in connection with the 16 companies the Working Group has identified as subjects of its RMBS investigations. The firm notes the “substantial expense” it has incurred “to educate an ever-growing, and often-changing, number government attorneys and investigators.” The firm argues that the Working Group’s most recent subpoena, which seeks “every document and communication for all 193 clients and for almost 5,000 e-mail custodians,” constitutes a “fishing expedition” and violates the firm’s rights under the Fourth Amendment.