Black Monday, the 1987 stock-market crash's record one-day percentage loss for the Dow, occurred on October 19, 1987.
The Dow Jones Industrial Average dropped 508 points, or 22.6%, in a single session. That remains the largest one-day percentage decline in the index's history. Stock markets in other countries also fell sharply, making the event an international crash rather than an isolated American slump.
Analysts have linked the fall to high valuations, rising interest rates, trade tensions, and computerized portfolio-insurance strategies. Those automated selling techniques could intensify a decline when markets moved rapidly, although no single explanation accounts for every part of the crash.
The episode differed from 1929 because the economy did not enter a comparable decade-long depression. The Federal Reserve, led by Alan Greenspan, said it would provide liquidity to the financial system, helping limit wider damage.