The worldwide stock-market collapse that began on October 19, 1987, was nicknamed Black Monday.
The name refers to the day when markets around the world experienced extraordinary losses. The Hong Kong market dropped first, and the selling wave moved west through Europe before reaching the United States. The Dow Jones Industrial Average fell 22.6%, while other major indexes also suffered severe declines.
The 1987 crash followed a strong multi-year rise in share prices. Investors were worried about interest rates, currency tensions, economic growth, and valuations. Portfolio insurance and other computer-assisted trading strategies encouraged further selling once prices began to fall.
“Black Monday” can also refer to other financial shocks, especially October 28, 1929, in some historical writing. In stock-market history, however, the phrase most commonly identifies October 19, 1987, unless a year is supplied. The crash led exchanges and regulators to introduce circuit breakers and coordinated emergency procedures.