Black Monday was the name of the October 19, 1987 stock-market crash, when the Dow Jones Industrial Average fell 22.6% in one session.
The decline spread across international markets after heavy selling in the United States. The crash followed several years of strong gains, rising interest rates, trade tensions, and growing use of computerized trading strategies. Portfolio insurance programs intensified selling as prices dropped.
The 1987 event is often confused with Black Monday dates in other financial crises. October 19, 1987 is specifically the date associated with the record one-day percentage fall in the Dow. The point loss was smaller than later crashes because the index stood at a much lower level than it does today.
Markets recovered relatively quickly compared with the Great Depression. Regulators later introduced circuit breakers and other measures intended to pause trading during exceptionally rapid declines.