On October 19, 1987, the Dow Jones Industrial Average plunged about 22.6 percent in a single trading day, a collapse remembered as Black Monday. It was one of the largest one-day percentage drops in U.S. stock market history. The crash followed a long rise in stock prices and was driven by a mix of concerns about valuations, interest rates, and automated trading. The sudden fall rattled investors and raised fears of a new depression. Central banks and regulators responded with steps to keep markets functioning and to reassure investors. While the economy slowed, it did not enter a severe depression, and new “circuit breaker” rules were later adopted to reduce the risk of similar crashes.
