What name is given to the extreme US market plunge that began on May 6, 2010?

The extreme US market plunge that began on May 6, 2010, is called the 2010 Flash Crash.

During a brief period that afternoon, major US equity indexes and individual securities moved violently downward before recovering much of the loss. The Dow Jones Industrial Average fell about 1,000 points, roughly 9%, in minutes. Some trades occurred at prices far outside normal market ranges.

Investigations by US regulators concluded that a large automated sell order, combined with stressed market conditions and high-frequency trading responses, helped produce the disruption. The event revealed how electronic markets could amplify a temporary imbalance between buyers and sellers.

The flash crash differed from a conventional bear market. It was exceptionally rapid and much of the index decline reversed quickly. Regulators subsequently introduced or strengthened safeguards, including market-wide circuit breakers, single-stock trading pauses, and clearer procedures for reviewing clearly erroneous trades. The episode remains an important case study in modern market microstructure.