Which U.S. stock-market event on May 6, 2010 briefly erased about $1 trillion in market value?

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

During the afternoon of May 6, major U.S. equity indexes plunged rapidly before recovering much of the loss within minutes. The Dow Jones Industrial Average fell about 1,000 points, or roughly 9%, at its session low. Many individual securities also traded at extraordinary prices.

Investigations by U.S. regulators linked the episode to interactions among high-frequency trading, market conditions, and a large automated sale of stock-index futures. The precise sequence was complex, and the event prompted changes to circuit breakers and trading safeguards.

The crash was temporary and differed from a conventional bear market. It also occurred more than two decades after Black Monday in 1987, which was a separate worldwide market shock.