The 1987 stock-market crash day when Hong Kong’s Hang Seng Index fell 11.1% is known as Black Monday.
On 19 October 1987, markets around the world suffered extraordinary losses. Hong Kong was among the first major markets to experience the shock because of time-zone differences, and the Hang Seng Index fell 11.1% that day.
The same nickname is most famously associated with the US market’s 22.6% Dow decline on that date. Using the identical name for different markets can create confusion, so the exchange and percentage must be identified when discussing the event. Hong Kong’s market remained closed for several days after the crash, and trading resumed amid continuing international anxiety.
The crash was linked to global economic concerns, market imbalances, and trading practices such as portfolio insurance. It also revealed how closely connected national exchanges had become. The episode encouraged regulators to create coordinated responses and helped establish temporary trading halts as a standard emergency tool.