What nickname describes the rapid stock-market collapse of October 1987?

Black Monday describes the rapid stock-market collapse of October 1987.

The name most specifically refers to October 19, 1987, when major stock markets plunged. The Dow Jones Industrial Average lost 22.6% in one session, while markets in Hong Kong, Australia, Britain, and other countries also recorded dramatic declines. Because trading occurred across time zones, the shock appeared as a chain of connected market falls rather than a single isolated national event.

Several forces contributed. U.S. shares had risen strongly, interest-rate and trade concerns unsettled investors, and automated selling strategies amplified the rush for the exits. Portfolio insurance was intended to limit losses, but its sell orders could add further pressure when prices dropped.

Black Monday is distinct from the Black Monday of October 28, 1929, which preceded Black Tuesday in the Wall Street crash. The same nickname has also been used for other financial disasters, so the year is important when identifying the event.