This article provides a good summary of how the Fed used its ability to lend to commercial banks as a tool for addressing the financial crisis that began in August 2007.
EXCERPT:
"Easing the terms of primary credit was one of the Federal Reserve’s first responses to the financial crisis. On August 17, 2007, the Federal Reserve reduced the spread of the primary credit rate over the FOMC’s target for the federal funds rate to 1/2 percentage point, from 1 percentage point, and lengthened the typical maximum maturity from overnight to 30 days. On December 12, 2007, the Federal Reserve created the TAF to further improve the access of depository institutions to term funding. On March 16, 2008, the Federal Reserve lowered the spread of the primary credit rate over the target federal funds rate to 1/4 percentage point and extended the maximum maturity of primary credit loans to 90 days.
Subsequently, in response to improving conditions in wholesale funding markets, on June 25, 2009, the Federal Reserve initiated a gradual reduction in TAF auction sizes. As announced on November 17, 2009, and implemented on January 14, 2010, the Federal Reserve began the process of normalizing the terms on primary credit by reducing the typical maximum maturity to 28 days.
The increase in the discount rate announced Thursday widens the spread between the primary credit rate and the top of the FOMC’s 0 to 1/4 percent target range for the federal funds rate to 1/2 percentage point. The increase in the spread and reduction in maximum maturity will encourage depository institutions to rely on private funding markets for short-term credit and to use the Federal Reserve’s primary credit facility only as a backup source of funds. The Federal Reserve will assess over time whether further increases in the spread are appropriate in view of experience with the 1/2 percentage point spread.
