Coruscation

Conventional loans, which conform to Fannie and Freddie underwriting guidelines, do not require upfront mortgage insurance. But some may require monthly private mortgage insurance, if the borrower puts less than 20 percent down toward the purchase, or has less than 20 percent equity in a refinancing.

F.H.A. borrowers, meanwhile, can stop paying the monthly mortgage insurance only after five years and when their loan-to-value ratio reaches 78 percent, at which point they have 22 percent equity in their home.

F.H.A. loans are typically offered by niche direct lenders, and because of the insurance, they often carry interest rates equal to or slightly below those of conventional loans.

In October, the F.H.A. set a minimum FICO score of 500 for borrowers who want an F.H.A.-insured loan -- the first time a minimum was set. It also introduced a new minimum down payment of 10 percent for borrowers with FICO scores below 580. (Those above 580 still pay a minimum 3.5 percent.)

The issue for the F.H.A, Mr. Harriott said, is that the realm of borrowers has widened. "We see executives of little companies, teachers, people making $200,000 a year, doing an F.H.A. loan, because they've gotten into a financial situation," he said, adding that F.H.A. loans are perceived as safe by investors because of the insurance.