NEW YORK -- Less than two weeks after the US government bailout of Fannie Mae, several leaders are leaving the company, including Peter Niculescu, promoted less than a month ago to become the mortgage giant's chief business officer.

Also leaving are Beth Wilkinson, general counsel; Chief Information Officer Rahul Merchant and lobbyist Duane Duncan, according to an internal memo obtained by Reuters.

The Federal Housing Finance Agency, which regulates Fannie Mae and rival Freddie Mac, announced about two weeks ago that it was placing them under conservatorship. It named Herb Allison as Fannie's CEO, replacing Daniel Mudd, and David Moffett as Freddie's CEO, replacing Richard Syron.

The US Treasury and the FHFA determined that neither company could sustain mounting mortgage losses and still offer critical aid to the broader housing markets. Treasury Secretary Henry Paulson worried that Wall Street would continue to shun their stock. Without investor cash, Fannie Mae and Freddie Mac would have to raise the costs of their mortgages and shrink their balance sheets just as policy-makers were relying on the companies to keep home buying costs low. Reporting by Helen Chernikoff; Editing by Derek Caney