Which 2010 market event briefly erased nearly $1 trillion from U.S. equities in minutes?

The 2010 market event that briefly erased nearly $1 trillion from U.S. equities was the 2010 flash crash. It occurred on May 6, 2010, during an already volatile trading session.

The Dow Jones Industrial Average plunged about 1,000 points, or roughly 9 percent, within minutes before recovering much of the loss. Individual securities experienced extreme and temporary price movements, including trades at fractions of a cent and unusually high prices. Automated and high-frequency trading systems amplified the rapid selling and recovery.

The U.S. Securities and Exchange Commission and Commodity Futures Trading Commission later concluded that a large sell order in E-mini S&P 500 futures interacted with market conditions and automated trading. The event led to reforms including circuit breakers and trading pauses. It was different from a traditional multi-day crash because much of the decline reversed on the same day.