Which 1987 crash date saw the Dow Jones Industrial Average fall 22.6% in one session?

19 October 1987 saw the Dow Jones Industrial Average fall 22.6 percent in one trading session, the largest one-day percentage decline in its history.

The date became known as Black Monday. Selling spread through major markets, including Hong Kong, London, and Australia, although the size and timing of declines differed by country and time zone. Investors were worried about high valuations, interest rates, trade tensions, and slowing economic growth.

Computerized trading and portfolio-insurance strategies are widely discussed as factors that accelerated the fall, but no single cause fully explains the crash. Unlike the 1929 collapse, the 1987 crash was followed by a relatively short recession and the Dow eventually recovered. The Federal Reserve, led by Alan Greenspan, helped reassure markets by emphasizing its support for the financial system.