In a move that took Wall Street insiders by surprise, Citigroup CEO Vikram Pandit is stepping down as the company's Chief Executive Officer and as a member of the Board, effective immediately.

Until more details emerge, it’s difficult to know what to make of Vikram Pandit’s sudden resignation from Citicorp. In recent years, the mighty Citi, once of America’s largest banks, has been humbled ...

FILE PHOTO: Vikram Pandit, chief executive officer of Citigroup Inc., speaks at the U.S. Export-Import Bank annual meeting in Washington, D.C., U.S., on Friday, April ...

* Michael Corbat named CEO * Pandit says he had considered leaving for some time * COO John Havens, a close Pandit associate, also resigns * Citigroup shares rise 1.6 percent By Carrick Mollenkamp and ...