The global stock-market crash in which Hong Kong’s Hang Seng fell 46% in five days occurred in 1987.
Black Monday began on October 19, 1987, when the Dow Jones Industrial Average in the United States dropped 22.6% in a single session. The shock spread rapidly through international markets. Hong Kong’s exchange was closed for several days, and when trading resumed, its Hang Seng Index suffered a cumulative fall of about 46% over five days.
The episode was not limited to one country or one exchange. Major indexes in Europe, Australia, Canada, and other Asian markets also recorded exceptional losses. Concerns about valuations, interest rates, currency relationships, and automated portfolio strategies all contributed to the crisis.
The year 1987 distinguishes this crash from the Asian financial crisis of 1997, which also caused a major fall in Hong Kong. Black Monday is specifically associated with the worldwide October 1987 collapse, while the Hang Seng’s 46% five-day loss describes the Hong Kong market’s particular experience.