Which index fell 22.6% on October 19, 1987, during the Black Monday crash?

The Dow Jones Industrial Average fell 22.6% on October 19, 1987, during the Black Monday crash.

The decline amounted to 508.32 points, taking the Dow from 2,246.74 at the previous close to 1,738.74. It remains the largest one-day percentage fall in the index’s history. The Dow tracks 30 prominent U.S. companies, so it is widely quoted as a market indicator, even though it does not represent every listed company.

Black Monday was part of a worldwide sell-off. Major markets in Hong Kong, Australia, the United Kingdom, and elsewhere also fell sharply. Concerns about trade deficits, interest rates, currency movements, and high valuations had already made investors nervous. Computerized trading systems and portfolio-insurance strategies then helped turn falling prices into accelerated selling.

The S&P 500 also dropped heavily that day, but the famous 22.6% figure belongs to the Dow Jones Industrial Average. This distinction matters because different indexes measure different collections of stocks and can show different percentage losses.