Which U.S. trading event on May 6, 2010 briefly erased nearly $1 trillion in market value?

The 2010 Flash Crash was the U.S. trading event on May 6, 2010, that briefly erased nearly $1 trillion in market value.

During the afternoon of May 6, major U.S. equity indexes plunged rapidly and then recovered much of the decline within minutes. The Dow Jones Industrial Average fell about 1,000 points, or roughly 9 percent, before rebounding. Some individual securities briefly traded at extremely low or high prices.

Investigations found that a large automated sell order in E-mini S&P 500 futures interacted with existing high-frequency trading and market conditions. The U.S. Securities and Exchange Commission and Commodity Futures Trading Commission described the interaction as a major contributor, rather than attributing the event to one simple error.

The episode exposed weaknesses in fragmented, automated markets. Regulators later introduced or strengthened safeguards such as single-stock circuit breakers and coordinated trading pauses. It was a market-structure shock, not a conventional multi-year economic depression.