During the 1987 Black Monday crash, the Dow Jones Industrial Average fell 22.6% in a single day.
On October 19, 1987, the Dow dropped 508 points, closing at 1,738.74. The percentage loss was the largest one-day percentage decline in the index’s history, a record that still stands. Stock markets in other countries also fell sharply, making Black Monday a genuinely global crash rather than an isolated U.S. event.
Several factors contributed, including investor anxiety about interest rates, trade imbalances, computerized trading strategies, and falling prices earlier in the month. The exact causes remain debated, but the scale of the decline is not: the Dow lost more than one-fifth of its value in one session.
This percentage is often confused with the 508-point loss. Points measure the index’s numerical change, while the percentage compares that change with the previous closing level. The Dow later recovered much of the decline, and regulators introduced market safeguards partly in response to the crash.