October was the first month of the 1987 crash in which the Dow Jones Industrial Average fell by more than 20%.
The decisive collapse occurred in October 1987, culminating in Black Monday on October 19. On that day, the Dow dropped 22.6%, its largest one-day percentage fall. The monthly decline was also historically severe because the market had already weakened before the single-day plunge.
Black Monday was part of a worldwide market shock. Major exchanges in Asia, Europe, and North America fell within a short period, demonstrating how increasingly connected financial markets had become. The crash was not followed by an economic depression in the United States.
The event is sometimes confused with the 1929 crash because both are associated with October and “Black” trading days. Their economic settings were different, however. In 1987, regulators and central banks acted quickly, and new trading safeguards were developed to reduce the risk of another uncontrolled cascade.