The 1987 crash in which the Dow Jones Industrial Average lost 22.6% in one trading session was Black Monday.
Black Monday occurred on October 19, 1987. The Dow Jones Industrial Average fell 508 points, equivalent to 22.6 percent, making it the largest one-day percentage decline in the index’s history. Major markets in Asia and Europe also suffered enormous losses, making the event global rather than solely American.
Several factors were discussed afterward, including overvalued shares, investor anxiety, portfolio insurance, computerized trading, and international economic tensions. No single universally accepted cause explains the entire decline. Trading systems and market rules were later reviewed, contributing to the introduction of circuit breakers designed to slow extreme falls.
Black Monday is sometimes confused with the October 1929 crash dates, which also carry “Black” labels. The 1987 event was not followed by a depression comparable to the 1930s, and the U.S. economy continued expanding afterward.