Fannie Mae said Wednesday that it will not only refuse to guarantee another loan for seven years if it has evidence that a borrower chose to default on their loan, and will seek to recoup losses in court through deficiency judgements in states that allow lenders such recourse.

There's a carrot-and-stick aspect to the new policy. Troubled borrowers who work with their servicer on foreclosure alternatives such as loan modifications, short sales, or deeds in lieu of foreclosure can be eligible for a new loan in two to three years if they can show extenuating circumstances such as job loss, illness or divorce.

"Walking away from a mortgage is bad for borrowers and bad for communities, and our approach is meant to deter the disturbing trend toward strategic defaulting," said Terence Edwards, Fannie Mae's executive vice president for credit portfolio management.