How long did the most intense phase of the 2010 Flash Crash last on U.S. markets?

The most intense phase of the 2010 Flash Crash lasted about 36 minutes on U.S. markets.

On May 6, 2010, major stock indexes fell rapidly and then recovered much of the decline before the trading day ended. The Dow Jones Industrial Average briefly lost nearly 1,000 points, one of its largest intraday point swings.

Investigations found that automated trading played an important role. A large sell order in E-mini S&P 500 futures interacted with high-frequency trading and rapidly changing liquidity, producing a feedback loop of selling and canceled orders. Some individual securities briefly traded at wildly abnormal prices.

The event did not represent a conventional months-long market crash. It was a sudden liquidity disruption within one session. Regulators later introduced measures such as market-wide circuit breakers and limits on certain extreme price moves to reduce the risk of similar disorder.