Fractional-reserve banking is the system of banking in all countries worldwide, under which banks that take deposits from the public keep only part of their deposit liabilities in liquid assets as a reserve, typically lending the remainder to borrowers. Bank reserves are held as cash in the bank or as balances in the bank's account at the central bank. Fractional-reserve banking differs from the hypothetical alternative model, full-reserve banking, in which banks would keep all depositor funds on hand as reserves.

A bank is a financial institution that accepts deposits from the public and creates a demand deposit while simultaneously making loans. Lending activities can be directly performed by the bank or indirectly through capital markets.