We don’t think that financial stability concerns should at this point detract from the need for monetary policy accommodation which we are continuing to provide. Of all the concerns raised about bond buying by the Fed, the risk it could prompt financial instability is the only one I find personally credible. Currently, asset prices are broadly in line with historical norms. Those who have been saying for the last five years that we’re just on the brink of hyperinflation, I think I would just point them to this morning’s CPI number and suggest that inflation is not really a significant risk of this policy. The Fed is extraordinarily sensitive to risks of financial market instability. (Referring to bond purchases by the Fed), It was at least somewhat effective, and given that we were at the limits of what conventional monetary policy could do, we felt that we needed to take additional steps. I’m not yet ready to conclude that very low interest rates are going to be a permanent condition.
~ Ben Bernanke, "Bernanke Says QE Effective While Posing No Immediate Bubble Risk", Bloomberg, January 16, 2014