The Dow Jones Industrial Average fell 22.6% on the worst single day of the 1987 crash.
On Monday, October 19, 1987, known as Black Monday, the Dow dropped 508 points, or 22.6%. It was the largest one-day percentage decline in the index’s history, exceeding the percentage fall seen on any single day during the 1929 crash.
The selling was global: major markets in Hong Kong, Europe, Australia, and elsewhere also suffered steep losses. Analysts have linked the episode to overvalued markets, rising interest rates, investor anxiety, and computerized portfolio-insurance trading, although no single explanation accounts for every feature of the crash.
The 1987 event did not produce a depression comparable to the 1930s. The U.S. Federal Reserve, led by Alan Greenspan, issued a statement supporting market liquidity, and the Dow later recovered its pre-crash closing level.