The 1987 crash in Hong Kong was also called Black Monday, preceding the same-day U.S. market collapse.
Hong Kong’s Hang Seng Index fell sharply on October 19, 1987, and its market was closed for several days afterward. Because Asian markets opened earlier than U.S. markets, the Hong Kong plunge formed part of the international sequence that investors watched as trading moved westward through time zones. The crisis culminated in dramatic losses in the United States and other major markets.
Black Monday is most commonly used for October 19, 1987, and the name can refer to the global crash or, especially, the U.S. Dow’s record one-day percentage fall. It is not the same as Black Monday in October 1929, nor the later Black Monday labels applied to unrelated market declines. Hong Kong’s episode is notable because the Hang Seng’s loss was exceptionally severe and helped show how interconnected markets had become.