The 1987 global stock-market crash’s Monday of record declines was called Black Monday.
Black Monday occurred on October 19, 1987. The Dow Jones Industrial Average fell 508 points, or 22.6 percent, in its largest one-day percentage decline. Major markets around the world also dropped sharply, including exchanges in Hong Kong, London, and Australia.
Several explanations have been studied. Portfolio insurance strategies encouraged automated selling as prices fell, while international market links, high valuations, and investor anxiety amplified the move. The crash exposed weaknesses in trading infrastructure and coordination among financial regulators.
The event did not produce a depression comparable to the 1930s. The U.S. Federal Reserve, led by Alan Greenspan, issued a statement affirming its readiness to provide liquidity. Exchanges also introduced circuit breakers afterward to pause trading during extreme price movements. This question concerns the 1987 event, not Black Tuesday in 1929.