The major U.S. market disruption on May 6, 2010, was the Flash Crash. During the event, U.S. equity indexes and individual securities plunged rapidly before recovering much of the loss within minutes.
The Dow Jones Industrial Average briefly fell nearly 1,000 points, or about 9%, its largest intraday point decline at that time. Many stocks, exchange-traded funds, and futures contracts traded at extremely unusual prices.
Investigations linked the episode to interactions among automated trading systems, market liquidity, and a large sell order in E-mini S&P 500 futures. The U.S. Securities and Exchange Commission and Commodity Futures Trading Commission later described how selling pressure moved through interconnected markets.
The Flash Crash did not resemble a conventional, months-long bear market. It was a sudden liquidity event that exposed how high-speed trading could amplify volatility. Regulators subsequently introduced safeguards including circuit breakers and single-stock trading pauses.