The 1987 global stock-market crash that began on Black Monday was called Black Monday. On October 19, 1987, major markets around the world fell sharply, with the Dow Jones Industrial Average dropping 22.6% in one session.
The decline followed a prolonged bull market, rising interest rates, trade tensions, and concerns about high valuations. Program trading and portfolio-insurance strategies accelerated selling, although historians continue to debate the precise balance of causes.
Black Monday is distinct from the 1929 Wall Street crash and from later market events that also used the nickname. It remains the largest one-day percentage fall in the Dow’s history, even though later crashes produced larger point losses because index levels were higher.