October 19, 1987, was known as Black Monday after the Dow Jones Industrial Average plunged 22.6% in a single trading session.
The fall was the largest one-day percentage decline in the Dow’s history. Stock markets in several countries also suffered major losses, making the event an international market crash rather than an isolated American shock. The decline followed substantial volatility and a sharp market rise earlier in the decade.
Analysts have associated the crash with factors including overvaluation, concern about trade deficits and interest rates, and computerized program trading. Portfolio insurance strategies could intensify selling when prices moved lower, although no single cause explains every market’s decline.
Black Monday is distinct from the October 1929 crashes, which produced the names Black Monday and Black Tuesday in a different historical episode. It is also distinct from later market sell-offs that reused the Black Monday label. Despite the extraordinary fall, the 1987 crash did not lead to a depression comparable to the 1930s Great Depression.