What was the name of the sudden U.S. equity-market collapse on May 6, 2010?

The sudden U.S. equity-market collapse on May 6, 2010, was called the Flash Crash.

During the afternoon of May 6, major U.S. stock indexes dropped rapidly before recovering much of the loss. The Dow Jones Industrial Average briefly fell nearly 1,000 points, an extraordinary move for a few minutes of trading. Prices in individual securities also became highly distorted, with some trades occurring at extremely low or high levels before being canceled under exchange rules.

Investigations found that automated trading, market liquidity and a large sell order in E-mini S&P 500 futures interacted in a destabilizing way. The event showed how interconnected electronic markets could amplify a temporary imbalance between buying and selling.

The Flash Crash was not a conventional multi-month bear market like the 1929 or 2008 collapses. It was a rapid, largely intraday dislocation. U.S. regulators later introduced measures such as single-stock trading pauses and strengthened market-wide circuit-breaker mechanisms.