The Dow Jones Industrial Average lost approximately 22.6% on October 19, 1987.
That Monday became known as Black Monday and remains the largest one-day percentage decline in the Dow’s history. The index fell 508 points, an extraordinary move for the era. Selling spread rapidly among international markets, although the size of losses varied from country to country.
Researchers have identified several contributing factors, including overvalued markets, rising interest rates, trade concerns, and computerized portfolio-insurance strategies. No single cause completely explains the global selling wave. Unlike the 1929 crash, the 1987 collapse was followed by a relatively quick economic recovery.
The 22.6% figure refers to the Dow’s percentage change, not the number of points lost. Point losses are not directly comparable across decades because the index’s level changes over time.