What name was given to the sharp U.S. stock-market plunge on October 19, 1987?

The sharp U.S. stock-market plunge on October 19, 1987, was called Black Monday.

The Dow Jones Industrial Average fell 22.6% on that Monday, the largest one-day percentage decline in its history. Selling was global: markets in Hong Kong, Australia, Europe, and North America recorded major losses during the episode.

The crash followed a period of rising equity prices and growing concern about interest rates, trade imbalances, and economic conditions. Computerized trading systems and portfolio-insurance strategies also became associated with the speed of the selling, although historians and economists do not attribute the event to one single cause.

Black Monday is sometimes confused with Black Tuesday, the best-known day of the 1929 Wall Street Crash. The labels refer to different market crises separated by nearly six decades. In both cases, the weekday name became a shorthand for a dramatic collapse.