May 6, 2010, was the date of the 2010 Flash Crash, a brief and dramatic plunge in U.S. financial markets.
During the afternoon, major U.S. equity indexes fell rapidly before recovering much of the loss. The Dow Jones Industrial Average dropped about 1,000 points, or roughly 9 percent, within minutes. Some individual securities traded at extremely unusual prices, although many transactions were later canceled under market rules.
Investigations concluded that automated trading and rapidly changing liquidity conditions played major roles. A large sell order in E-mini S&P 500 futures interacted with high-frequency trading and other algorithmic activity, creating a feedback loop that intensified the decline. The event prompted reforms in trading controls, including circuit breakers and safeguards for individual securities.
The Flash Crash was not the same as the 1987 Black Monday crash or the 2008 financial crisis. It was exceptionally fast, with much of the disruption occurring and reversing within a short period rather than unfolding over months or years.