Through its discount and credit operations, Reserve Banks provide liquidity to banks to meet short-term needs stemming from seasonal fluctuations in deposits or unexpected withdrawals. Longer term liquidity may also be provided in exceptional circumstances. The rate the Fed charges banks for these loans is the discount rate (officially the primary credit rate).
By making these loans, the Fed serves as a buffer against unexpected day-to-day fluctuations in reserve demand and supply. This contributes to the effective functioning of the banking system, alleviates pressure in the reserves market and reduces the extent of unexpected movements in the interest rates 1. For example, on September 16, 2008, the Federal Reserve Board authorized an $85 billion loan to stave off the bankruptcy of international insurance giant American International Group (AIG) 2, 3.