The reserve requirement sets the minimum reserves each bank must hold to demand deposits and banknotes. This type of regulation has lost the role it once had, as the emphasis has moved toward capital adequacy, and in many countries there is no minimum reserve ratio. The purpose of minimum reserve ratios is liquidity rather than safety. An example of a country with a contemporary minimum reserve ratio is Hong Kong, where banks are required to maintain 25% of their liabilities that are due on demand or within 1 month as qualifying liquefiable assets.
Reserve requirements have also been used in the past to control the stock of banknotes and/or bank deposits. Required reserves have at times been gold coin, central bank banknotes or deposits, and foreign currency.