On what date did the stock-market crash known as Black Monday occur?

The stock-market crash known as Black Monday occurred on October 19, 1987.

On that day, stock prices collapsed across many markets. The Dow Jones Industrial Average fell 22.6 percent, its largest one-day percentage decline. Markets in other countries also experienced severe losses, making the event an international financial shock rather than an isolated U.S. exchange disturbance.

Researchers and historians identify several contributing factors, including high valuations, economic concerns, rising interest rates, international tensions, and the growing use of computerized trading strategies. No single explanation accounts for every part of the crash.

The 1987 event also influenced market-structure reforms. U.S. exchanges later adopted circuit breakers designed to pause trading during extreme declines, giving participants time to assess rapidly changing conditions. Black Monday is different from the 1929 crash and from the sharp market fall on Black Monday in 2020.