Those most likely to claim the highly protected mortgage interest tax deduction are higher-income earners in mainly 10 states.

Taxpayers with an adjusted gross income of $100,000 or more accounted for just 13% of all returns in 2008 but claimed 47% of all mortgage interest and property tax deductions, according to a Government Accountability Office study released Monday.

Those making less than $100,000 made up the other half of the claims but represent 87% of all returns.

"Higher-income households are generally more likely to itemize and claim the mortgage interest and property tax deductions, because they have larger amounts to claim. Moreover, they also have received greater tax savings from the two deductions," GAO researchers said.

More than half of taxpayers claiming the mortgage interest tax deduction resided in 10 states – California, New York, New Jersey, Illinois, Maryland, Virginia, Massachusetts, Colorado, Washington, and Connecticut. But these states accounted for just more than one-third of all returns in 2008.

Home sales are usually higher along the coasts, giving a smaller percentage of borrowers more value to claim. Most claimants also lived in urban areas.

According to the GAO, 91% of taxpayers claiming a mortgage interest tax deduction lived in the city. The remaining 9% lived in rural areas, even though these more rural taxpayers accounted for nearly 20% of all returns.

Republicans rejected putting mortgage interest tax deduction protections on their official party platform until the National Association of Realtors and other trade groups pressured the party this year to backtrack.

Both candidates President Obama and Mitt Romney have said on the campaign trail they would scale back such deductions for the wealthiest Americans.

jprior@housingwire.com