S&P 500 · December 4, 1987

The Black Monday slide

-33.51%

peak-to-trough, the whole slide

71 trading days · 1987-08-25 → 1987-12-04

back to the old high on 1989-07-26

What happened that day?

From the 25 August 1987 peak to the 4 December low the S&P 500 fell 33.51% — 71 trading days
Black Monday, 19 October, sits in the middle of it — still the worst single day on record
The market was already sliding before that, drifting down from the August high on worries about rates and the trade deficit
What made the crash so violent was program trading — software that sold automatically once prices fell past a line, and everyone used the same line
Falling triggered selling, selling triggered more falling. Orders piled up faster than the exchanges could process them
The lasting result was circuit breakers — rules that halt US trading outright when prices drop too fast
The old high returned on 26 July 1989

Sources

Every figure on this page is recomputed from the original daily closing prices and checked against them at build time. The account of what happened is written from the sources listed above.