The Dow Jones Industrial Average lost 22.6% on the worst day of the 1987 stock-market crash.
The fall occurred on October 19, 1987, when the Dow dropped 508 points. That percentage decline remains the largest single-day percentage fall in the index’s history. Markets in other countries also plunged, making the event a truly global crash rather than an isolated American sell-off.
Several factors contributed to the panic, including high valuations, concerns about economic conditions, international currency tensions, and automated portfolio-insurance strategies. Computerized trading could accelerate selling once prices began to fall, although the crash had multiple causes rather than one universally accepted trigger.
The 1987 event is sometimes confused with the 1929 crash because both are associated with dramatic October selling. Unlike the early 1930s, however, the 1987 crash was not followed by a comparably prolonged depression.