Goldman (GS), you may have heard, was sued last month by the Securities and Exchange Commission. The SEC, led by Mary Schapiro (right), claims Goldman ripped off some investors in a subprime-related debt issue by failing to make clear that a hedge fund manager named John Paulson was betting against the deal — and helping to select the investments. Goldman says it did nothing wrong.

So how does this affect Citi (C)? Well, in Friday’s quarterly filing with regulators, the New York-based megabank made a big reveal. For the first time, it says, it has received subprime-related subpoenas from the SEC.

Citi’s filing said (on page 176) that it “continues to cooperate fully in response to subpoenas and requests for information from the Securities and Exchange Commission and other government agencies in connection with various formal and informal inquiries concerning Citigroup’s subprime mortgage-related conduct and business activities.”

Not that this comes as a great shock. Citi has disclosed before that its actions in the subprime mess and the larger credit crisis are the subject of legal interest from all angles. The firm spent the better part of two pages (at pages 263-265) in its annual regulatory filing detailing the scrutiny it faces from regulators, federal agencies, and plaintiff’s lawyers.

“Beginning in the fourth quarter of 2007, certain of Citigroup’s regulators and other state and federal government agencies commenced formal and informal investigations and inquiries, and issued subpoenas and requested information, concerning Citigroup’s subprime mortgage-related conduct and business activities,” the firm said then. “Citigroup is involved in discussions with certain of its regulators to resolve certain of these matters.”

Friday’s filing adds to the year-end filing in one way: in this one, Citi mentions the SEC by name.

A Citi spokesperson declines to comment on whether Citi received any subpoenas from the SEC in the first quarter but stresses that “there has been no change in the dialogue” with regulators.