A bank run occurs when a large number of bank customers try to withdraw their deposits at the same time, usually due to concerns about the solvency of the bank or a lack of confidence in the banking system as a whole.

A bank run can be triggered by various factors, such as rumors about the bank's financial stability, a sudden economic downturn, or a major news event that erodes public trust in the banking system.

Bank runs can be particularly damaging to the affected bank, as they can quickly deplete the bank's reserves and lead to insolvency. In some cases, governments may intervene to prevent bank runs and protect depositors' funds.