Fannie Mae Chief Executive Officer Michael Williams announced his resignation Tuesday, saying he will officially step down as soon as the mortgage-finance giant names a successor. Williams didn't specify a reason for his departure except to say that "the time is right to turn over the reins to a new leader." He may be smart to get out now as the firm continues to struggle with its finances. In November, Fannie Mae reported a net third-quarter loss of $5.1 billion, forcing them to ask for another $7.8 billion in federal funding. After the financial crisis in 2008, regulators forced Fannie Mae and its sibling, Freddie Mac, to depend on government help to cover losses on owned or guaranteed mortgages. Both Williams and Freddie Mac CEO Ed Haldeman have been scrutinized for their large paychecks ($6 million each, with bonuses), and Haldeman announced in October that he plans to resign at some point in 2012 as well.