The plan centers on Fannie Mae and Freddie Mac, which between them own or back about 31 million mortgages worth a combined $5 trillion. The federal government took over the firms in September due to mounting losses on their portfolios of mortgages.

Eligibility is determined by several factors: Homeowners must be 90 days or more late in their mortgage payments, owe at least 90% of their home's current value, live in the home on which the mortgage was taken and have not filed for bankruptcy.

Their mortgage payments would be adjusted through lower interest rates or longer repayment schedules with the goal of bringing payments below 38% of monthly household income. Interest rates could be lowered for five years and then raised to a predetermined level. Loan terms could be lengthened to 40 years.

Officials said the standards for loan modifications should fast-track changes in payments. The standards will be applied to loans owned and guaranteed by Fannie and Freddie, but officials said they hope they will also be adopted industry wide.

“We expect that it could significantly increase the number of modifications completed,” said James Lockhart, director of the Federal Housing Finance Agency, the regulator that oversees Fannie and Freddie. …

Fannie reported this week that 1.7% of its mortgages by value are delinquent by 90 or more days. Fannie's filings suggest that it has about 18 million mortgages on its books, which would work out to about 300,000 mortgages that could potentially be eligible. The borrower will ultimately be responsible for paying the full amount of the principal borrowed, but payment on part of the principal can be deferred to make the monthly payment affordable.

Homeowners who purposefully default on their mortgage to get a modification will not be eligible. Borrowers will have to submit a statement showing financial hardship or a change in financial circumstances, along with proof of their income. The modification will become final once a borrower has made three payments under the modified terms. But even in cases where declining home prices have taken the value of a home to less than is owed on the mortgage, the balance of the loan will not be lowered under this program.

“This is not loan forgiveness; the loans will be paid but at terms affordable for borrowers,” said Brian Montgomery, commissioner of the Federal Housing Administration.

The fact that mortgage balances will not be reduced for the so-called underwater mortgages — those in which a homeowner owes more than the home is worth — will limit the use and impact of the program, according to some experts.

However, there is a competing interest in getting modifications done and that is the investors who purchased these loans. Some hedge funds, including Greenwich Financial Services and Braddock Financial, told banks in October that they might sue the banks if they changed mortgages that were within mortgage bonds that the hedge funds had purchased. Modifying the terms of mortgages underlying mortgage bonds can change how much those bonds are worth.

Investor rules and underlying servicing contracts with respect to modifications are not uniform and may prevent us from doing modifications that would benefits borrowers and investors.

Under the plan, Fannie Mae, Freddie Mac and other mortgage firms will rewrite the terms on some overdue mortgages so the homeowners won't pay more than 38% of their monthly income. Modifications could include deferring some of the principal owed, lowering interest rates or extending maturities to as much as 40 years. The process will be streamlined and uniform.