The 2010 Flash Crash unfolded over about 36 minutes, from roughly 2:32 to 3:08 p.m. Eastern Time on May 6, 2010.
During that period, major U.S. equity indexes plunged rapidly before recovering much of the loss. The Dow Jones Industrial Average fell nearly 1,000 points, or about 9%, at its worst point, although the market ended the day down substantially less.
A joint investigation by U.S. regulators concluded that a large automated sell order, combined with high-frequency trading and deteriorating liquidity, helped trigger and amplify the move. Some individual securities briefly traded at wildly abnormal prices.
The event showed how computerized trading systems could interact unexpectedly during stress. It led to measures including single-stock circuit breakers and market-wide mechanisms intended to prevent a similar cascade.