Bank Reserve

Bank reserves are the currency deposits which are not lent out to the bank's clients. A small fraction of the total deposits is held internally by the bank or deposited with the central bank. Minimum reserve requirements are established by central banks in order to ensure that the financial institutions will be able to provide clients with cash upon request.

The main purpose of holding reserves is to avoid bank runs and generally appear solvent. Central banks place these restrictions on banks, because the banks can earn a much larger return on their capital by lending out money to clients rather than holding cash in their vaults or depositing it with other institutions. Bank reserves decrease during periods of economic expansion and increase during recessions.