The abrupt May 6, 2010 US market plunge and rapid rebound was called the Flash Crash.
During the afternoon of May 6, major U.S. stock indexes dropped rapidly before recovering much of the loss. The Dow Jones Industrial Average briefly fell about 1,000 points, or roughly 9%, within minutes. Some individual securities experienced far more extreme temporary price movements.
Investigations by U.S. regulators concluded that a large sell order in E-mini S&P 500 futures interacted with high-frequency trading and automated market-making systems. As liquidity disappeared, algorithms amplified the decline and created unusual price volatility.
The event differed from a conventional long-lasting bear market because the most dramatic movement occurred in minutes and prices rebounded quickly. Regulators later introduced measures including trading pauses, minimum quoting requirements, and procedures for reviewing clearly erroneous trades.