In 2006, the Congress had approved plans to allow the Fed, beginning in 2011, to pay interest on banks' reserve balances. In the fall of 2008, the Congress moved up the effective date of this authority to October 2008.

A higher IOER rate encourages banks to raise the interest rates they charge, putting upward pressure on market interest rates regardless of the level of reserves in the banking sector. While adjusting the IOER rate is an effective way to move market interest rates when reserves are plentiful, federal funds have generally traded below this rate.

Paying interest on reserve balances enables the Fed to break the strong link between the quantity of reserves and the level of the federal funds rate and, in turn, allows the Federal Reserve to control short-term interest rates when reserves are plentiful.

Janet Yellen Quotes