Many experts say reducing mortgage principal can help troubled homeowners avoid foreclosure and stay in their homes. But the regulator who oversees two of the nation's largest mortgage holders, Fannie Mae and Freddie Mac, has rejected the idea. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images

Federal Housing Finance Agency Acting Director Edward DeMarco during testimony before Congress in December. Chip Somodevilla/Getty Images hide caption

itoggle caption Chip Somodevilla/Getty Images