Which 1987 market crash is known by the weekday name Black Monday?

The 1987 market crash known as Black Monday occurred on October 19, 1987.

On that Monday, the Dow Jones Industrial Average plunged 508 points, a fall of 22.6%. The percentage decline was larger than on any other day in the Dow’s history. Selling quickly spread from Hong Kong and Australia through Europe and into the United States, demonstrating how closely linked major financial markets had become.

Several conditions contributed: stock prices had risen sharply, interest rates were increasing, the U.S. trade deficit was a concern, and investors feared that economic growth might weaken. Portfolio insurance and other computerized trading strategies automatically generated additional sell orders as prices fell.

The name can cause confusion because “Black Monday” has also been used for other market declines, including October 28, 1929, and October 27, 1997. In the context of the landmark global crash, however, Black Monday specifically means October 19, 1987.