What date is known as Black Monday, when global stock markets suffered a historic 1987 collapse?

Black Monday, the 1987 global stock-market crash, occurred on October 19, 1987. The Dow Jones Industrial Average fell 22.6% in a single session, its largest one-day percentage decline.

The selling began in Hong Kong and spread westward through Europe and North America. Investors were worried about trade tensions, rising interest rates, slowing economic growth, and a rapidly expanding use of computerized trading strategies.

The crash was not a repeat of the 1929 collapse, although the nickname caused confusion. Markets stabilized relatively quickly, and the Dow recovered much of its decline over subsequent months. The episode also encouraged regulators to develop circuit breakers that could temporarily halt trading during extreme volatility.