The 1992 currency-market crisis when speculators forced Britain out of the European Exchange Rate Mechanism was called Black Wednesday.
On September 16, 1992, the British government tried to keep the pound within the ERM’s permitted exchange-rate band. Speculators, including George Soros, bet that Britain could not maintain the pound’s value without imposing economically damaging interest-rate increases.
After emergency rate rises and other interventions failed, the United Kingdom suspended the pound’s ERM membership. The government’s attempt to defend sterling produced heavy losses and became a major political embarrassment.
Black Wednesday was principally a currency and policy crisis rather than a stock-market crash. It matters in crash history because it shows how exchange-rate commitments, interest rates, and speculative pressure can destabilize financial markets.