October 19, 1987, the worst one-day percentage fall in Dow Jones Industrial Average history, was called Black Monday.
The Dow Jones Industrial Average fell 508 points, or 22.6%, on that day. The decline followed sharp losses in markets across Asia and Europe and was intensified by computerized trading strategies, including portfolio insurance. Investors sold rapidly as prices dropped, creating a feedback loop of falling prices and more selling.
The crash was global rather than limited to the United States. Hong Kong’s market fell especially sharply, and major European markets also recorded very large losses. The U.S. market later recovered, but the 1987 episode remains distinct from the 1929 crash because the percentage collapse was much larger in a single day.
Black Monday is sometimes confused with other market days using the same nickname, including October 28, 1929, and October 19, 1987. In stock-market history, the unqualified term usually refers to the 1987 event.