What nickname was given to the rapid U.S. market plunge on October 19, 1987?

The rapid U.S. market plunge on October 19, 1987, was nicknamed Black Monday. The Dow Jones Industrial Average fell 22.6 percent that day, the largest one-day percentage decline in its history.

The name follows a tradition of assigning “black” labels to severe market panics. Earlier examples include Black Thursday and Black Tuesday during the 1929 Wall Street Crash. Because several financial crises have used similar names, the year is essential when identifying the event.

Black Monday was not limited to the United States. Stock markets in Europe, Asia, and other regions also suffered large losses as selling moved across time zones. The episode demonstrated how interconnected major financial markets had become.

The crash prompted reviews of trading systems and risk controls. U.S. exchanges later adopted circuit breakers that can pause trading after unusually large index movements, giving participants time to absorb information.