During the October 1987 global stock-market crash, which market recorded the largest one-day percentage fall?

During the October 1987 global stock-market crash, the Hong Kong Stock Exchange recorded the largest one-day percentage fall.

On October 19, 1987, commonly called Black Monday, Hong Kong’s stock market fell about 45.8 percent. The collapse was part of a worldwide market panic that rapidly spread across financial centers. By comparison, the Dow Jones Industrial Average in the United States fell 22.6 percent that day, its largest one-day percentage decline in history.

The Hong Kong market’s fall is sometimes confused with the U.S. crash because Black Monday is most closely associated with Wall Street in popular accounts. However, the percentage decline in Hong Kong was substantially larger. Other major markets also dropped sharply, including Australia, the United Kingdom, and Canada.

The crash exposed how increasingly connected international markets had become. Program trading, investor panic, expensive valuations, and concerns about economic conditions all contributed to the sell-off. Central banks and governments responded with measures intended to restore confidence and market liquidity.