During the May 6, 2010 Flash Crash, approximately how long did the steepest market plunge last?

During the May 6, 2010 Flash Crash, the steepest market plunge lasted about 36 minutes.

U.S. stock markets fell rapidly in the afternoon, with the Dow Jones Industrial Average temporarily losing nearly 1,000 points before recovering much of the decline. Some individual securities briefly traded at extraordinarily low prices, creating disorder across exchanges and electronic trading venues.

The U.S. Securities and Exchange Commission and the Commodity Futures Trading Commission later concluded that a large automated sell order interacted with high-frequency trading and market conditions to intensify the fall. The event also exposed differences in how trading systems handled rapidly changing prices.

The crash was unusually brief compared with traditional bear markets. It did not represent a normal, months-long collapse in company values. Regulators introduced measures including single-stock circuit breakers and market-wide safeguards to reduce the risk of similar extreme dislocations.