At the end of last year, Fannie alone had packaged and guaranteed about $2.8 trillion worth of mortgages, approximately 23% of all outstanding U.S. mortgage debt. And these securities are highly rated and sold to investors all over the world.
"If Fannie or Freddie failed, it would be far worse than the fall of [investment bank] Bear Stearns," says Sean Egan, head of credit ratings firm Egan Jones. "It could throw the economy into depression or something close to it."
"The major issue is that these are very leveraged financial institutions, leveraged much more than any other bank, and they have lots of mortgage assets. As real estate values decline every day, the value of [the mortgages that it bundles, guarantees, and sells] are called into question,
Freddie alone will need to raise $7 billion over the next two quarters due to writedowns and losses. But the company's market capitalization - the number of outstanding shares times the share price stands at $8.7 billion.
If Fannie and Freddie were unable to buy and back loans, banks would stop originating them and the pool of homebuyers would shrink, causing home prices to fall even further.
Fannie and Freddie are among the most highly-leveraged companies around, meaning the amount of capital they have on hand is nowhere close to the level of assets they control.
Fannie and Freddie must constantly borrow money in order to operate; if for any reason borrowing costs rose sharply they would not be able to make good on their guarantees or even fund their day to day operations. This is when the government would feel intense pressure to step in and, at the very least, pay contracts in a timely manner.
In an April report, Standard & Poor's said an Armageddon scenario whereby Fannie and Freddie are insolvent is unlikely, but that the mere possibility of failure at either is a greater threat to the economy than the actual collapse of any investment bank.
The doomsday scenario could cost taxpayers more than $1 trillion, says the S&P report. The report went so far as to say that a government bailout of Fannie or Freddie could force the agency to lower its rating on the creditworthiness of the United States