On what date did the 2010 United States stock-market flash crash occur?

The 2010 United States stock-market flash crash occurred on May 6, 2010.

During that afternoon, major U.S. equity indexes fell sharply within minutes before recovering much of the decline. The Dow Jones Industrial Average dropped nearly 1,000 points, or about 9%, intraday.

Investigations found that automated trading, rapidly changing liquidity, and a large sell order contributed to the disorder. A later U.S. Justice Department case identified trader Navinder Singh Sarao as a participant whose spoofing activity was linked to the event, although the crash resulted from interacting market conditions rather than one simple cause.

The episode led regulators and exchanges to introduce or strengthen circuit breakers and other safeguards. It also demonstrated how electronic markets could move at extraordinary speed even without a conventional economic announcement.