Fannie Mae’s privileges as a government-chartered company are likely to survive congressional scrutiny following the ouster of the housing lender’s chief executive because of accounting mistakes.

Senator Shelby, the Republican chairman of the finance committee, doesn’t want to end Fannie’s government perks, spokesman Andrew Gray said. Democrats such as Rep. Artur Davis vowed to defend the privileges.

The $10 billion in annual benefits, according to the Congressional Budget Office, include a $2.25 billion line of government credit and exemptions from state and local taxes. The perks are needed to help low-income Americans buy homes, Mr. Davis said. Lawmakers of both parties agree that the focus will be on increasing regulatory scrutiny of Fannie Mae, which is the biggest source of money for the American mortgage industry.

“What we have to do, I believe, is pass comprehensive legislation to put together a strong regulator,” Mr. Shelby of Alabama said in a Bloomberg TV interview December 22. “This type of legislation is well overdue.”

The point of contention is likely to be receivership, said Mr. Davis, who represents Alabama in the House of Representatives and sits on the financial services committee. Receivership would allow for bankruptcy, potentially diluting the implied government guarantee Fannie-backed mortgages now have.

“I’m not sold on the idea of receivership,” Mr. Davis said.

Shelby said Republicans want a regulator who can take receivership of Fannie Mae if it were to become insolvent.

There is room for compromise on oversight, according to Rep. Barney Frank of Massachusetts. He and other Democrats draw the line at ending the company’s ties to the government. Mr. Frank wouldn’t support changing Fannie Mae’s business model, said his spokeswoman, Kay Gibbs.

The debate about government oversight of Fannie was stoked last week by the ouster of Fannie Mae’s chief executive, Franklin Raines, and its chief financial officer, J.Timothy Howard.

Fannie announced Mr. Raines’ early retirement and Mr. Howard’s resignation on December 21, after the Securities and Exchange Commission said the week before that Fannie Mae made mistakes in accounting for contracts designed to protect its more than $900 billion of securities from swings in interest rates. Fannie Mae said it may have to restate profit by $9 billion as a result.

Mr. Shelby and Rep. Michael Oxley of Ohio, Republican chairman of the House Financial Services Committee, are planning hearings next month and February on Fannie Mae and competitor Freddie Mac. Mr. Shelby said he wouldn’t support any legislation that doesn’t include receivership power for the regulator.

Republican lawmakers want a regulator to curtail the growth of Fannie Mae and Freddie Mac and protect against destabilizing financial markets, forcing a government buyout. The companies own or control about half the $7.6 trillion mortgage market.

Congress chartered Fannie Mae and Freddie Mac to make funds more available for home loans. Fannie Mae, started by Congress in 1938, went public in 1970. That year, Congress created Freddie Mac, which was first publicly traded in 1989. The companies have retained privileges granted by the government that allow them to offer lower rates than many banks.

Since Mr. Raines was fired on December 21, at least three analysts have raised their ratings of Fannie Mae shares and none have lowered them, according to Bloomberg data.

A Sanford C. Bernstein & Company analyst who has rated the stock “outperform” since 2000, Jonathan Gray, said possible regulatory changes by Congress range from “changes that are ineffective to changes that restrict their growth.”

“It is highly unlikely any changes will be made that will enhance their growth,” he said.

For six years, lawmakers have discussed greater regulation of Fannie Mae, said Charles Gabriel, a political analyst and senior vice president at Prudential Equity Group.

“Wall Street has been aware of these proposals,” Mr. Gabriel said. “That’s why the stock has been stagnant during the five years of Raines’s tenure.”

“The debate is obviously going to be much more serious” now, he said. “The presumption is we are going to have legislation, with Fannie and Freddie at their weakest point ever in terms of their ability to defend themselves.”

Fannie Mae created a political action committee this year, according to PoliticalMoneyLine, contributing $248,750 to the Democrats and $264,100 to Republicans. The company gave $250,000 to each party convention host committee, and spent $8.7 million to lobby in 2003.

Freddie Mac began a PAC this year and gave $26,000 to Democrats and $42,500 to Republicans. The company gave $261,000 to the Democratic convention host committee and $300,000 to the Republican host committee, according to PoliticalMoneyLine. Last year, Freddie Mac spent $15.9 million on lobbying.

Mr. Davis said he would consider a Republican proposal giving the Treasury Department and the Housing and Urban Development Department a dual role in regulating Fannie Mae and Freddie Mac. The problems will be in the details, such as how to resolve conflicts between Treasury and HUD, Davis said.

The companies currently are regulated by the Office of Federal Housing Enterprise Oversight, which lawmakers have criticized as weak.

Rep. Paul Gillmor, Republican of Ohio, wants to end the advantages the companies receive from the government. Rep. Richard Baker, a Louisiana Republican who leads a Financial Services subcommittee overseeing Fannie Mae, proposed legislation giving receivership power to a regulator.

Rep. Joseph Crowley, a Democrat of New York, in a written statement criticized “overreaching by Chairman Baker, who has consistently come out against” the companies.

Record sales of homes helped double the mortgage portfolios at the two companies over the past five years to $1.6 trillion. Fannie Mae had net income of $7.91 billion in 2003, up from $3.91 billion in 1999. Raines earned $20 million last year in base salary, bonus, stock grants and long-term incentive payments, an 8 percent increase from 2003.

Until 2002, Fannie Mae and Freddie Mac were exempt from filing financial statements with the Securities and Exchange Commission.

A bill creating a regulator stalled in the Senate this year primarily because of opposition to a receivership provision by Senator Paul Sarbanes of Maryland, senior Democrat on the Senate Banking Committee, and other lawmakers.

In the event of insolvency, receivership would let a federal regulator liquidate the companies and distribute compensation in a way that limits taxpayer losses at the expense of unsecured creditors. Merrill Lynch & Co. has said such authority could hurt the companies’ credit ratings and increase their cost of borrowing.

Receivership is necessary for a regulator to exercise any authority, said Steve Bartlett, president of the Financial Services Roundtable, a Washington lobbying group for brokerages that support increased regulation.

The threat of receivership would bring Fannie Mae and Freddie Mac into line, he said.

“You have receivership to make sure they get properly regulated,” Mr. Bartlett said.