The 1987 global stock-market crash was called Black Monday.
On 19 October 1987, the Dow Jones Industrial Average plunged 508 points, or 22.6%, in its largest one-day percentage decline. The fall began in Hong Kong, spread through Europe, and reached the United States after markets opened.
The crash was international rather than solely American. Stock markets in Australia, Canada, Hong Kong, and the United Kingdom also suffered severe losses. In the United States, program trading, portfolio insurance, rising interest rates, and investor anxiety were among the factors examined afterward.
Black Monday is often confused with the 1929 Wall Street crash, which had several famous collapse days. The 1987 event was followed by regulatory changes, including new circuit breakers designed to pause trading during extreme declines.