As investors grew more convinced that only some type of government bailout could rescue the firms, Treasury Secretary Henry Paulson said the focus was to support the pair "in their current form" without a takeover.
The government was considering giving Fannie and Freddie access to the Fed's emergency lending program as one option to prop up the firms, said Sen. Christopher Dodd, D-Conn., citing conversations with Fed Chairman Ben Bernanke and Paulson.
A Fed spokeswoman said the central bank had not talked with Fannie and Freddie about the emergency lending program. The spokeswoman declined to discuss any other options being considered.
Both companies issued statements late Friday calling their financial positions solid. Freddie Mac said it did not see an immediate need to raise fresh money, and said other options included cutting its annual shareholder dividend, which costs $650 million a year.
Investors drove Fannie and Freddie shares to 17-year lows before the stocks recovered somewhat. The turmoil, combined with a new high for oil prices, helped send the Dow Jones industrials briefly below 11,000 for the first time in nearly two years. The Dow finished down about 1 percent at 11,100.54.
Fannie and Freddie were created by the government to provide more Americans the chance to own a home by adding to the available cash banks can loan customers. Shares of both companies are publicly owned.
Their importance to the housing market and overall economy is hard to overstate: Fannie and Freddie either hold or back $5.3 trillion of mortgage debt, or about half the outstanding mortgages in the United States.
"Without them, our economy would collapse," Piper Jaffray analyst Robert P. Napoli said in a note to clients.
In the mortgage industry, the prospect of doing business without Fannie and Freddie is truly frightening.
"The cost of borrowing would go up dramatically," said Steve Habetz, president of Threshold Mortgage Co. in Westport, Conn. "We would be going back to dark ages where a homebuyer would be hoping that a local bank would (have enough resources) to make the loan that it will keep on its books."
Published reports suggested the government was considering taking over one or both of the companies and running them itself.
President Bush met with senior economic advisers and said Paulson had assured him that Paulson and Federal Reserve Chairman Ben Bernanke "will be working this issue very hard."
Wall Street sent the companies' stocks lower nonetheless. Freddie Mac shares were down 25 cents, or 3.1 percent, to $7.75. Fannie Mae shares were down $2.95, or 22.4 percent, to 10.25.
"I think everybody's just holding their breath in expectation that something substantive from the government will happen today or over the weekend," said Karen Shaw Petrou, managing partner of consulting firm Federal Financial Analytics.