The mortgage giants were taken over by the government on Sept. 7, as their mounting defaults and foreclosures threatened the entire mortgage market. The move was an attempt to help reverse a prolonged housing and credit crisis.

Both Fannie Mae and Freddie Mac were being placed in a government conservatorship, a move that could end up costing taxpayers billions of dollars.

Prior to this move, on July 23, the U.S. House passed a bill to help homeowners facing foreclosure and to keep Fannie and Freddie from collapsing.

The two companies hold or guarantee more than $5 trillion in mortgages - almost half of the nation's total.

<<< Click on the questions at left for answers about their role in the mortgage market and what the bill entails. Credits:  CBS News, The Associated Press, Fannie Mae, Freddie Mac