The Bush administration is considering at least four candidates to head the regulator of Fannie Mae and Freddie Mac, the largest sources of money for American home loans, people familiar with the search said.

Jonathan Fiechter, a deputy director at the International Monetary Fund; Edward DeMarco, assistant deputy commissioner at the Social Security Administration; Mark Sullivan, the U.S. representative to the European Bank for Reconstruction and Development, and Steve McMillan, an adviser to White House Chief of Staff Andrew Card; are among the candidates, said the people, including a senior government official who deals regularly with the regulator.

The Bush administration in May began seeking a new director of the Office of Federal Housing Enterprise Oversight to replace Stephen Blumenthal. Congress is currently debating legislation that would create a tougher regulator for Washington-based Fannie Mae and McLean, Va.-based Freddie Mac, which have made more than $15 billion of accounting errors.

Anyone offered the post “is going to have to ask themselves whether they want to take a job that may be overseeing the unwinding of” the agency, said Josh Rosner, an analyst at Medley Global Advisors.

Messrs. Fiechter, DeMarco, Sullivan, and McMillan didn’t reply to phone messages requesting comment.

The new Ofheo director should be “familiar with the housing markets and familiar with financial markets generally and a strong executive,” the Treasury undersecretary for domestic finance, Randal Quarles, said. “The administration will continue to look for someone with those capacities.”

Mr. Fiechter in 2003 joined the IMF as deputy director of the monetary and financial system department after three years as senior deputy comptroller at the Office of the Comptroller of the Currency. Mr. DeMarco, before join ing the SSA in 2003, was director of the Treasury’s Office of Financial Institutions Policy, where he helped develop regulation toward Fannie Mae and Freddie Mac.

Mr. McMillan, a former aide to retired Texas Senator Phil Gramm, became an adviser to Mr. Card last month after serving in the office of White House Budget Director Josh Bolton. Mr. Sullivan became the U.S. representative to the EBRD in 2002, rejoining Treasury where he served as general counsel from 1988 until 1989.

The House passed legislation creating a stricter regulator on October 26. Senate legislation approved by the banking committee in July hasn’t gone to the floor for a vote even though the committee’s chairman, Senator Shelby of Alabama, identified the bill as his top priority for 2005.

Democrats and some Republicans on the banking committee, along with Fannie Mae and Freddie Mac, oppose a provision requiring a new regulator to cut the companies’ combined $1.4 trillion mortgage portfolios. The holdings generate about two-thirds of profit at the government-chartered companies, which own or guarantee almost half the $7.6 trillion mortgage market.