The 2010 Flash Crash caused a sudden plunge in major United States stock indexes on May 6, 2010.
During the afternoon of May 6, the Dow Jones Industrial Average dropped about 1,000 points, or nearly 9%, within minutes. Prices in many securities moved with extraordinary speed, and some trades occurred at wildly unusual levels before markets largely recovered.
Investigations concluded that a large automated sell order, combined with fragile market conditions and high-frequency trading activity, helped create a feedback loop of selling and disappearing liquidity. The US Securities and Exchange Commission and Commodity Futures Trading Commission later described the event as involving interactions among automated systems rather than a single simple mistake.
The episode is called a flash crash because much of the decline and recovery happened extremely quickly. It was not the same as the prolonged 2008 financial crisis. New safeguards, including circuit breakers and changes to market-wide trading controls, were introduced or strengthened afterward.