Fractional-reserve banking, the most common form of banking practiced by commercial banks worldwide, involves banks accepting deposits from customers and making loans to borrowers while holding in reserve an amount equal to only a fraction of the bank's deposit liabilities. Bank reserves are held as cash in the bank or as balances in the bank's account at a central bank. The country's central bank determines the minimum amount that banks must hold in liquid assets, called the "reserve requirement" or "reserve ratio". Banks usually hold more than this minimum amount, keeping excess reserves.