The official name of the 2010 U.S. market crash caused by rapid automated selling was the Flash Crash.
On May 6, 2010, U.S. stock indexes fell suddenly and then recovered much of the decline within minutes. The Dow Jones Industrial Average dropped about 1,000 points, roughly 9%, during the session before rebounding.
Investigations found that automated high-frequency trading and a large sell order in E-mini S&P 500 futures interacted in ways that rapidly removed liquidity. Some individual securities briefly traded at extremely low or high prices, demonstrating how electronic markets could behave during a liquidity shock.
The event led regulators and exchanges to introduce or strengthen safeguards, including circuit breakers and rules for clearly erroneous trades. It was not the same as the 1987 Black Monday crash, which involved a much larger percentage decline in the Dow over a full session.