NEW YORK (CNNMoney.com) -- The Bush administration is set to unveil on Tuesday a potentially extensive new program to modify mortgages and help at-risk homeowners and stabilize the battered real estate market.

The plan centers on Fannie Mae and Freddie Mac, which between them own or back about $5 trillion in loans. The federal government took over the firms in September due to mounting losses on their portfolios of mortgages.

While a number of major banks, including Citigroup (C, Fortune 500), JPMorgan Chase (JPM, Fortune 500) and Bank of America (BAC, Fortune 500), have announced loan modifications programs in recent weeks, they hold only a fraction of the nation's mortgages compared with Fannie and Freddie.

Despite calls from members of Congress and some housing advocates for the government to take a more direct role in preventing foreclosures, federal agencies have been slow to present their own plans to modify the loans of millions of homeowners at risk.

The rest of this article is here:  http://money.cnn.com/2008/11/11/news/economy/loan_modification/index.htm