Which index suffered the largest single-day point loss during the 2010 United States flash crash?

The Dow Jones Industrial Average suffered the largest single-day point loss during the 2010 United States flash crash.

On May 6, 2010, the Dow fell about 1,000 points in minutes, including a roughly 573-point drop in a short period. The S&P 500 and Nasdaq Composite also plunged before recovering much of the loss by the close.

A joint investigation by US regulators concluded that a large automated sell order in E-mini S&P 500 futures helped trigger an extreme liquidity event. High-frequency trading firms and other automated systems responded rapidly, while available buyers temporarily disappeared in many securities.

The episode showed that modern markets could move extraordinarily fast even without a conventional economic shock. Some individual stocks briefly traded at implausible prices, and several trades were later canceled under exchange rules. Regulators subsequently strengthened safeguards, including market-wide circuit breakers and controls for clearly erroneous trades. The crash was brief, unlike the prolonged declines of 1929 or 2008.