Servicers who lower distressed homeowners’ mortgage payments by reducing the principal balance, as opposed to just making interest rate adjustments, are much more likely to see the payments keep coming in and ward off a redefault, according to a new study published by the “Federal Reserve Bank of New York”:http://newyorkfed.org.

The economists found a definite pattern among modifications made since December 2005 that suggests “an intention among servicers to make the loans more affordable, while not losing any of the underlying principle.” However, their analysis shows that modifications that trim off some of the loan balance have higher rates of success and “can double the reduction in re-default rates.”

While principal writedowns essentially mean the lender or investor must eat a loss, many analysts argue that it’s a smaller loss than comes with the eventual foreclosure and the price tag of a nonperforming asset in today’s housing market, already swollen with REO inventories and vacant properties.

According to the New York Fed’s economists, when a borrower’s monthly mortgage payment is cut by 25 percent by reducing the interest rate only, the borrower is 11 percent less likely to default within one year.

But, if the monthly payment is lowered by the same 25 percent, this time by shaving 25 percent off of the outstanding loan balance, coupled with a small interest rate cut, the chances that the borrower will defaulting again within one year drops by nearly 27 percent.

The report’s authors also concluded that borrowers who have a loan-to-value (LTV) ratio of 115 percent or higher – meaning they owe 15 percent or more than their homes are worth – pose a 51 percent higher risk of redefaulting after a modification.

According to a blog by Wall Street Journal reporter Nick Timiraos, the findings of the New York Fed paper could have big implications on the administration’s Home Affordable Modification Program (HAMP).

Timiraos explained that while the program doesn’t preclude principal forgiveness on the part of lenders, HAMP’s primary push is on lowering interest rates and extending the loan term to bring monthly payments down – exactly the types of modifications that the Fed report says have a higher chance of becoming delinquent again.

The Congressional Oversight Panel and the special inspector general for the Troubled Asset Relief Program (TARP) have criticized the government’s mortgage modification efforts on numerous occasions for not addressing the issue of negative equity, which would ultimately involve trimming LTV ratios by shaving off outstanding mortgage balances.

A growing number of mortgage experts and foreclosure counselors agree with the federal watchdogs and the New York Fed economists that principal reduction is a powerful incentive for borrowers to keep up with their restructured payments, particularly now, when such a large number of mortgages are underwater.

First American CoreLogic says that nearly 10.7 million, or 23 percent, of the residential mortgages in the United States had negative equity at the end of the third quarter of 2009, with the homeowner owing more on the home than it was worth. A modification is only worthwhile if it induces borrowers who would otherwise default to continue paying, the New York Fed’s economists noted, and they argue in their analysis that borrowers with positive equity in their properties have a strong incentive to keep current on their mortgage, since delinquency and foreclosure will ultimately lead to a loss of the asset.

“In fact,” they wrote, “borrowers with positive equity (that is, borrowers whose house is worth more than the balance on their mortgage) should rarely default, since refinancing the mortgage or selling the property are better options than foreclosure, which may cause the borrower to lose [their] equity.”