The 1987 U.S. market crash that began in Hong Kong before spreading west was called Black Monday.
On October 19, 1987, the Dow Jones Industrial Average fell 508 points, or 22.6%, its largest one-day percentage decline. The selling followed sharp falls in Asian and European markets and spread rapidly through increasingly interconnected financial systems.
Analysts have identified several contributing factors, including overvalued shares, rising interest rates, trade tensions, portfolio insurance, and computerized program trading. No single explanation accounts for every feature of the crash.
The date is called Black Monday in the United States, although the Hong Kong market fell first on October 19 local time. The crash was not the same as the October 1929 collapse, and the U.S. economy did not experience a depression comparable to the 1930s after 1987.