Fannie Mae and Freddie Mac will receive guidance from their regulator on developing contingency plans for failed lenders and servicers by the first quarter of 2013.

Both government-sponsored enterprises identified 300 counterparties that either sell home loans to them or service mortgages on their behalf as of September 2011. The GSEs stopped doing business with more than 40 of them, according to a report from the Federal Housing Finance Agency Inspector General.

Fannie and Freddie lose their ability to force failed lenders to buyback faulty mortgages and can face late fees on insurance and tax obligations handled by servicers that go out of business. Legal fees from counterparty bankruptcy pile up from settled claims against the GSEs, and transferring loans to another servicer also comes with additional costs.

Since entering conservatorship in 2008, the GSEs took $6.1 billion in losses from the failures of just four counterparties and could lose $7.2 billion more from current exposure.

Both GSEs monitor watch lists of risky counterparties, but FHFA examiners have not detailed guidance for detailing contingency plans should one lender or servicer fail.

"The enterprises can benefit from published FHFA guidance about when counterparties' volume and concentration of business raise their risk enough to warrant contingency plans," the FHFA-IG said.

FHFA directors of GSE regulation and policy Jon Greenlee and Fred Graham wrote in a response letter to the inspector general that teams are testing a finalized draft examination manual with the guidance in it.

"The manual's section on counterparty risk management includes a number of specific requirements relating to the timing, content and implementation of contingency plans, which have informed supervisory work and communication to date," Greenlee and Graham wrote.