The 2010 market event in which U.S. stock indexes plunged rapidly before recovering was the Flash Crash.
On May 6, 2010, major U.S. equity indexes suddenly dropped and then rebounded within minutes. The Dow Jones Industrial Average briefly fell about 1,000 points, or roughly 9 percent, its largest intraday point decline at that time.
Investigations by U.S. regulators concluded that a large automated sell order in E-mini S&P 500 futures interacted with existing high-frequency trading activity and reduced market liquidity. The event showed how electronic markets could move sharply when many automated systems responded to one another.
Some individual securities recorded extraordinary temporary prices, including Accenture, whose shares briefly appeared to trade at one cent on some venues. The Flash Crash was not a conventional multi-day economic collapse like 1929 or 2008. It was a rapid, largely intraday market dislocation that prompted new circuit-breaker and trading controls.