FEDERAL RESERVE DEPOSITS: Deposits that commercial banks keep with the Federal Reserve System. Federal Reserve deposits, together with vault cash are the bank reserves that banks use to back up customers' deposits and otherwise conduct daily transactions, such as processing checks and satisfying customers cash withdrawals. Federal Reserve deposits play three key roles in the banking system. One, they are used by the Federal Reserve system to process of clear checks. Two, they are loaned between commercial banks through the federal funds market. Three, they are used by the Federal Reserve System to control the money supply. See also | Federal Reserve System | Federal Reserve Bank | bank | Federal Open Market Committee | monetary policy | money creation | federal funds market | federal funds rate | federal funds | bank reserves | vault cash |