Fannie Mae said it is lobbying for "substantive" changes in a proposed risk-based capital rule that is under review by the Office of Management and Budget.
Fannie Mae's vice chairwoman, Jamie Gorelick, said the enterprise does not want to be locked into a risk-calculation model it hasn't had a hand in creating.
At issue is the amount of capital Fannie and Freddie Mac would have to set aside to weather a worst-case economic scenario.
"We want them to get to a different substantive result," she said of the proposal from the Office of Federal Housing Enterprises Oversight, which oversees the financial health of the two government-sponsored enterprises. "We want our own models but with a set of factors specified in the regulatory process."
Ms. Gorelick said Congress did not contemplate that the OFHEO would create a "self-contained model that would substitute for the models being used by the companies."
The proposal is favored by banks and other lenders who argue that Fannie and Freddie enjoy an advantage in the marketplace due to an implied government guarantee on their debt, and that they should be required to set aside capital to cover their risks.
Fannie and Freddie "do not have the incentive to hold an amount of capital commensurate with the risks that they pose to the housing and financial markets and, in the event of insolvency, possibly the government," said Mark A. Kinsey, acting director of the oversight office.
The proposal has been in the OMB's hands for four months, including two extensions of two weeks each. The delay prompted banking groups and one key House member to complain to OMB director Jacob Lew.
A source familiar with the situation said the OMB asked for a third extension Wednesday.
In a speech last month, Mr. Kinsey said the law requires the OFHEO to develop a single model-a stress test that will "require the enterprises to hold enough capital to remain solvent during a 10-year period of severe credit and interest rate stresses"-that can be applied equally to Fannie and Freddie.
Fannie's and Freddie's internal stress test models were developed for their own business purposes, he said, adding that each model is "significantly different from the other.
"If they were used for regulatory purposes, they would result in unequal capital requirements," he said.
Jonathan E. Gray, an analyst and principal at Sanford C. Bernstein & Co., said he sees a simpler solution than imposing a risk-based capital rule.
He said that if Fannie and Freddie used subordinated debt-debt not backed by the government-it could "completely eliminate any risk of loss for the taxpayer" and eliminate the need for the OFHEO. "You could have hearings for an afternoon and deal with it," he said.
The issue has become a "political football," said Thomas O'Donnell, senior analyst at Salomon Smith Barney. He said the companies have been stress-tested in the marketplace by such events as the downturn in the California housing market and downturns in the bond market in the early 1990s.
In a letter Wednesday to Mr. Lew, the OMB director, the Bankers Roundtable, the American Bankers Association, the Consumer Bankers Association, the Consumer Mortgage Coalition, and America's Community Bankers complained about the lengthy review period.
And Rep. Richard H. Baker, R-La., chairman of the House subcommittee on capital markets, securities, and government-sponsored enterprises, wrote to Mr. Lew on Friday urging a quick conclusion.
"I am eager to receive the rule for congressional review and to then see it become public so all affected parties can express their views and concerns," Rep. Baker wrote.
"Should that next step not occur, I believe further inquiry by this subcommittee might be merited in the form of hearings or otherwise to address issues associated with the inability of OMB to clear the proposal in a timely manner."
