Unusually Uncertain

The Fed Chairman indicated that the pace of economic growth was "unusually uncertain."

But with decided certainty the Fed has made permanent a floor of $2.33 trillion in its balance sheet up from $878 billion at the end of 2007.

This freshly printed $1.5 trillion will be rolled over into US Treasury Bonds by reinvesting the principal received from US agency (fannie mae, freddie mac) bonds.

Fed Reverses Exit Plans, Sets $2 Trillion Floor for Holdings - Bloomberg