Which exchange suffered the largest single-day percentage fall during the 1987 global stock-market crash?

The Hong Kong Stock Exchange suffered the largest single-day percentage fall during the 1987 global stock-market crash. On October 19, 1987, Hong Kong’s Hang Seng Index fell 46.1%, an exceptionally severe decline during the worldwide episode.

The Hong Kong market had already experienced sharp volatility before trading was suspended for several days. When it reopened, selling pressure reflected both local concerns and the turmoil spreading through international financial centers. The crash then moved across markets in Europe and North America, showing how increasingly connected global exchanges had become.

The New York market’s 22.6% Dow decline is more famous, but it was not the largest percentage fall among major exchanges that day. Hong Kong’s result is also distinct from the Hang Seng’s later crashes, including those connected to the 1997 Asian financial crisis. Exchange percentages can differ because each market uses its own index, trading hours, and rules.