During the 1987 global stock-market crash, the Dow fell 22.6% on Black Monday.
On October 19, 1987, the Dow Jones Industrial Average plunged 508 points, or 22.6%, in a single trading session. It was the largest one-day percentage decline in the index’s history, and it occurred despite the absence of a single event comparable to a national financial collapse.
Several pressures were present, including high valuations, rising interest rates, trade tensions, and concerns about economic growth. Computerized portfolio-insurance strategies and other automated selling mechanisms amplified the downward move as prices dropped.
Markets in other countries also fell sharply. Hong Kong’s market crashed first in the sequence, and major European and Pacific markets recorded severe losses. The United States later introduced circuit breakers, although the specific safeguard connected with unusually large price movements is a separate question from the crash itself.