In a letter to U.S. Senator Chris Dodd, Fed Chairman Ben Bernanke said it is impossible to tell when markets will normalize and that the Fed is constantly reviewing its monetary policy tools to make them more effective.

Responding to a request from Dodd for the Fed to consider student loans at the Term Securities Lending Facility, Bernanke responded that banks could already pledge student loans as collateral.

Bernanke also called on Congress to consider the government's reimbursement rate.

By Erik Kevin Franco and edited by Stephen Huebl