Which exchange was forced to close for several days during the 1987 Black Monday crisis?

The Hong Kong Stock Exchange was forced to close for several days during the 1987 Black Monday crisis.

Hong Kong’s market closed from October 20 through October 23, 1987, after international selling and severe losses created operational and financial pressures. When trading resumed, the Hang Seng Index plunged, contributing to the worldwide sense that the crash was spreading rapidly across time zones.

The New York Stock Exchange did not close during the main 1987 crash, although trading was exceptionally disorderly and later regulations introduced circuit breakers. London and Tokyo also experienced major declines but remained open. The Hong Kong episode illustrates how a crash can move from one market to another as exchanges open at different times. It also helped prompt discussions about clearing systems, settlement risk, and coordinated market safeguards.