On what date did the 1987 stock-market crash reach its worst day, when the Dow fell 22.6%?

The 1987 stock-market crash reached its worst day on October 19, 1987, when the Dow Jones Industrial Average fell 22.6%.

The date is widely known as Black Monday. The Dow’s one-day percentage loss remains the largest in its history, even though later crashes produced larger point declines because the index had grown substantially.

Selling spread rapidly across international markets. Concerns about high valuations, trade tensions, rising interest rates, portfolio insurance, and automated selling all contributed to the panic, although historians and economists continue to debate the precise balance among these factors.

Black Monday is sometimes confused with Black Tuesday, October 20, when several markets began recovering. It is also distinct from Black Thursday, October 24, 1929, an early episode of the Wall Street Crash.