Bank reserves or central bank reserves are banks' holdings of deposits in accounts with their central bank (for instance the European Central Bank or the Federal Reserve, in the latter case including federal funds), plus currency that is physically held in the bank's vault ("vault cash"). The some central banks set minimum reserve requirements, which require banks to hold deposits at the central bank equivalent to a specified percentage of their liabilities such as customer deposits. Even when there are no reserve requirements, banks often opt to hold some reserves—called desired reserves—against unexpected events such as unusually large net withdrawals by customers or bank runs.
In relation to bookkeeping the term is a misnomer. Reserves are ordinarily part of the equity of the company and are therefore liabilities. Bank reserves, on the other hand, are part of the bank's assets. In a bank's annual report, they are referred to as "cash and balances at central banks".
- Reserves on deposit – deposit accounts at the central bank, owned by banks.
- Vault cash – reserves held as cash in bank vaults rather than being on deposit at the central bank.
- Borrowed reserves – bank reserves that were obtained by borrowing from the central bank.
- Non-borrowed reserves – bank reserves that were not obtained by borrowing from the central bank.
- Required reserves – the amount of reserves that banks are required to hold, determined by the central bank as a function of a bank's deposit liabilities.
- Excess reserves – bank reserves in excess of the reserve requirement. A portion of excess reserves (or even all of them) may be desired reserves.
- Free reserves – the amount by which excess reserves exceed borrowed reserves. (Vogel 2001:421)
- Total reserves – all bank reserves: vault cash plus reserves on deposit at the central bank, also borrowed plus non-borrowed, also required plus excess.
- In the case of the Federal Reserve System in the United States, see, e.g., Regulation D, at 12 C.F.R. sec. 204.5(a) and 12 C.F.R. sec. 204.2(k).
Vogel, Harold L. (2001). Entertainment Industry Economics: A Guide for Financial Analysis. New York: Cambridge University Press. ISBN 0-521-79264-9