The 1987 global stock-market crash that saw the Dow fall 22.6% in one day was called Black Monday.
On October 19, 1987, the Dow Jones Industrial Average dropped 508 points, or 22.6%, then the largest one-day percentage decline in its history. Selling spread rapidly to other markets, including Hong Kong, London, and Australia, making the event a genuinely international crash rather than an isolated U.S. sell-off.
Program trading, portfolio insurance, overvalued shares, rising interest rates, and investor fear all featured in explanations of the collapse. No single cause fully accounts for the event. Unlike the 1929 crash, Black Monday was not followed by a decade-long depression, and major economies continued to grow.
The name can cause confusion because “Black Monday” is also used for other market disasters. In this context, it specifically identifies October 19, 1987, and not the 1987 market decline as a whole.