What nickname was given to the sudden US stock-market plunge on May 6, 2010?

The sudden US stock-market plunge on May 6, 2010, was called the Flash Crash.

The Dow Jones Industrial Average briefly plunged nearly 1,000 points, or about 9%, during the afternoon session before recovering much of the loss. Many individual securities experienced extreme and short-lived price movements, including trades at implausibly low or high prices.

Investigations found that automated and high-frequency trading played a major role. A large sell order in E-mini S&P 500 futures interacted with already stressed markets and automated systems, causing liquidity to disappear rapidly. The US Securities and Exchange Commission and Commodity Futures Trading Commission issued a joint report on the event.

The episode differed from a conventional bear market because its most violent movement occurred within minutes and partially reversed the same day. It led to reforms including market-wide circuit breakers and tighter controls on erroneous trades.