The crash that began when the Dow Jones Industrial Average fell 508 points on October 19, 1987, was Black Monday.
The 508-point loss represented a 22.6% decline, the largest one-day percentage fall in the Dow’s history. Because the Dow’s level was much lower than it is today, the point figure is less useful for comparison than the percentage figure, but it remains a widely quoted measure of the event’s severity.
Black Monday was international: Asian and European markets had already weakened, and selling continued across global exchanges. Analysts identified several contributing pressures, including interest-rate concerns, trade disputes, stretched valuations, and computerized trading strategies.
The crash did not produce the prolonged economic collapse associated with 1929. Financial authorities responded quickly, and the Dow eventually recovered, although the event permanently changed views about market risk and trading-system design.