After unveiling a fourth round of long-term asset purchases, or quantitative easing, and a new threshold-based guidance, the Federal Reserve has put itself on a path of unlimited purchases of Treasuries and residential mortgage-backed securities (RMBS) until the unemployment rate falls.

FORBES: 2013 Is Bernanke's Year: Unlimited QE And Total Control Of The Fed

In late December the Treasury Department said it would provide unlimited support to Fannie Mae and Freddie Mac, and wouldn't force them to sell securities they hold.

WSJ: Fed Plan to Stop Buying Mortgages Feeds Recovery Worries