Back to the trough for Fannie and Freddie?

Are Fannie Mae (FNM) and Freddie Mac (FRE) heading out on the fundraising circuit again? The big mortgage companies’ regulator, the Office of Federal Housing Enterprise Oversight, seems to be saying yes. OFHEO director James Lockhart tells Bloomberg in an interview published Friday that the companies may raise as much as $20 billion in new capital as part of last week’s deal freeing them to expand their purchases of mortgage securities. Fannie and Freddie raised almost $15 billion in new capital by selling preferred stock and cutting their dividends late last year, after hefty losses tied to souring mortgage markets depleted their cushions against future losses.

Lockhart’s comments come just two weeks after Freddie execs insisted they had enough capital to see their way through the housing mess. But that was before the government gave Fannie and Freddie and another government-sponsored entity, the Federal Home Loan Banks system, more leeway to buy mortgage-backed securities in a bid to support that market, which has been hit by the flight of risk-averse investors. News of the agreement, which also led OFHEO to pare back some capital surcharges on Fannie and Freddie, sent the companies’ shares soaring last Wednesday, as investors bet the move would boost revenue growth.

Fannie and Freddie will need to raise the capital “sooner rather than later,” Lockhart told Bloomberg this week. But for now, investors seem to be betting that sooner won’t be all that soon. Shares of the companies were down just 2% in midmorning action Friday.