And it's likely to rise still further: The "robo-signing" settlement reached in February requires the country's five major mortgage servicers to perform at least $10 billion in write-downs, mostly on loans that they own, to atone for illegal foreclosures. Now principal reduction is nipping at the heels of Fannie Mae and Freddie Mac. Many consumer advocates and policymakers are calling for the twin mortgage guarantors to adopt the loss-mitigation tactic, but so far the mortgage giants' conservator, the Federal Housing Finance Agency, has resisted.