Hong Kong's one-day stock-market crash on October 19, 1987, was also known as Black Monday.
The Hang Seng Index fell 46.2% between October 19 and October 26, 1987, with trading suspended for several days during the turmoil. The collapse occurred as markets around the world reacted to the global Black Monday shock that began in the United States.
Hong Kong's market was particularly vulnerable because of its links to international capital and the fixed exchange-rate system connecting the Hong Kong dollar to the U.S. dollar. The extreme volatility overwhelmed the exchange's systems and contributed to the decision to halt trading temporarily.
Black Monday usually refers to October 19, 1987, but the phrase describes events in several markets. The U.S. Dow's one-day fall was 22.6%, while Hong Kong's measured decline over the surrounding trading period was much larger.