It's shaping up as the biggest government bailout in history.

Fannie Mae and Freddie Mac, the government-sponsored mortgage finance firms, have already received a total of more than $85 billion as part of the Federal bailout program.

Fannie got $34.2 billion in taxpayer money; Freddie got $51.7 billion.

But it seems that's not enough, by half. Estimates now forecast the two giants will need about $200 billion total before they can stand on their own two financial feet again.

'We're assuming they each will cross the $100 billion mark fairly soon,” Bose George, a mortgage analyst at Keefe, Bruyette & Woods, told CNN.

That figure is pathetically under the $25 billion the Congressional Budget Office forecast last year that Fannie and Freddie would need to regain solvency.

When the CBO made that prediction in July, 2008, it said there was only a 5 percent chance that Fannie and Freddie would ultimately need $100 billion combined, according to CNN.

The firms still hold trillions of dollars in mortgage loans, some of which they own outright, others which they've guaranteed.

But don't worry. Uncle Sam won’t let Fannie or Freddie fall.

"Fannie Mae and Freddie Mac are so large and so interwoven in our financial system that a failure of either of them would cause great turmoil in our financial markets here at home and around the globe," said Secretary of the Treasury Henry Paulson, quoted recently in The Wall Street Journal.