The 2010 Flash Crash caused an extraordinary intraday U.S. market plunge on May 6, 2010.
During the afternoon, major U.S. equity indexes dropped rapidly and then recovered much of the loss. The Dow Jones Industrial Average fell about 1,000 points, or nearly 9 percent, within minutes before rebounding. Some individual securities briefly traded at extremely low or high prices.
Investigations concluded that automated trading and a large sell order in E-mini S&P 500 futures helped interact with existing market stress. The event exposed weaknesses in fragmented, high-speed markets and highlighted how algorithms could reinforce one another.
The Flash Crash was not a conventional multi-month bear market. It was a sudden market-structure event lasting minutes. Regulators later introduced measures such as single-stock circuit breakers and market-wide safeguards to reduce the chance that extreme orders would spread unchecked.