A bank run is a series of unexpected large cash withdrawals from a bank caused by a sudden decline in depositor confidence or fear that the bank will be closed by the chartering agency, i.e. many depositors withdraw cash almost simultaneously. Since the cash reserve a bank keeps on hand is only a small fraction of its deposits, a large number of withdrawals in a short period of time can deplete available cash and force the bank to close and possibly go out of business. Bank runs are a risk for every bank that operates under a fractional-reserve banking system.
- Mankiw, N.G. Principles of Macroeconomics; South-Western Cengage Learning; Mason, OH. Page 353, (2008)