The Flash Crash was the 2010 market event in which U.S. stocks briefly lost and recovered nearly $1 trillion in value.
On May 6, 2010, major U.S. equity indexes plunged within minutes before recovering much of the decline. The Dow Jones Industrial Average fell about 1,000 points, roughly 9 percent, during the session, while some individual securities briefly traded at absurdly low prices.
Investigations linked the episode to a combination of automated high-frequency trading, large orders, market liquidity problems, and feedback between trading systems. The event differed from a conventional multiday bear market because the most dramatic fall and rebound occurred in a very short period. It led regulators and exchanges to introduce safeguards such as circuit breakers and improved trading controls.