What was the nickname of the rapid U.S. market collapse on May 6, 2010?

The rapid U.S. market collapse on May 6, 2010, became known as the Flash Crash.

During the afternoon, major U.S. stock indexes and many individual securities dropped extremely quickly before recovering much of the loss. The Dow Jones Industrial Average briefly fell nearly 1,000 points, an unusually large intraday move at the time. Prices became highly unstable, with some securities trading at implausibly low or high prices.

Investigations found that automated and high-frequency trading played an important role in the event. A large sell order in E-mini S&P 500 futures interacted with existing market conditions and automated trading activity, worsening the temporary imbalance between buyers and sellers. The event showed how modern electronic markets could transmit stress in seconds.

The Flash Crash differed from a traditional bear market because much of the decline and recovery occurred within minutes. Authorities later introduced or strengthened controls such as circuit breakers and single-stock trading pauses. The event remains an important case study in market structure and algorithmic trading.