Black Wednesday was the 1992 currency crisis that forced the United Kingdom to leave the European Exchange Rate Mechanism on September 16.
The ERM required participating currencies to remain within agreed bands against one another. Speculators, most famously including George Soros's Quantum Fund, bet that sterling could not remain above its required lower limit. The British government raised interest rates and announced further measures, but the pressure continued.
Britain suspended sterling's ERM membership on September 16, 1992, a day later known as Black Wednesday. The event was a currency and exchange-rate crisis rather than a conventional stock-market crash, but it produced major financial-market turmoil and political consequences. The pound later depreciated, while the episode damaged the reputation of the government led by John Major. Black Wednesday should not be confused with the stock-market Black Monday of 1987 or the later Black Wednesday labels used for other market events.