Despite the policy tightening that took place between June 2004 and June 2006, when the Fed brought its target for overnight interest rates up from 1 % to 5¼ %, long-term interest rates have not significantly changed. Chairman Bernanke believes that there is still somewhat of a “global savings glut,” characterized by large amounts of available global savings (especially from developing countries like China and energy producing nations) relative to investment opportunities. As those savings are made available to the U.S., in the form of demands for U.S. assets from abroad, there is upward pressure exerted on U.S. asset prices and, correspondingly, downward pressure exerted on the yields on those assets. Those forces are, according to Bernanke’s “global savings glut” hypothesis, helping to keep long-term U.S. interest rates relatively low.