During the 2010 Flash Crash, about 1,000 Dow points disappeared intraday before much of the loss reversed.
On May 6, 2010, U.S. equity markets experienced an exceptionally rapid collapse and partial recovery. The Dow Jones Industrial Average fell about 998.5 points, or roughly 9%, within minutes before recovering much of the decline by the close.
A later U.S. investigation concluded that a large automated sell order in E-mini S&P 500 futures interacted with high-frequency trading and market conditions to amplify the move. The event also exposed weaknesses in how fragmented markets handled extreme order flow.
The crash was not the same as a normal bear market. It unfolded in minutes rather than months, and many individual securities briefly traded at wildly abnormal prices. New safeguards, including trading pauses and improved coordination, were developed afterward.