During the 1987 global crash, which market recorded the largest one-day percentage fall, at about 45.8%?

The Hong Kong Stock Exchange recorded the largest one-day percentage fall during the 1987 global crash, dropping about 45.8%.

The collapse began in Hong Kong on 19 October 1987 and spread rapidly through international markets. Hong Kong’s Hang Seng Index suffered its biggest daily percentage decline during the episode, while other exchanges recorded very large losses over the same period.

The New York market’s decline on 19 October became the event’s best-known image: the Dow Jones Industrial Average fell 22.6%, its largest one-day percentage drop. Program trading, portfolio insurance, valuation concerns, and international market links were all examined afterward.

The Hong Kong figure is often overlooked because “Black Monday” is usually associated with New York. The global nature of the crash means that the market with the most famous fall was not the market with the largest percentage decline.