S&P 500 · September 27, 2002

September, testing the lows before a war

-3.23%

single-day change vs previous close

Part of a longer stretch

The dot-com bust hits the S&P 500

near the end of it · 2000-03-24 → 2002-10-09, -49.15% over the whole period

What happened that day?

27 September 2002 — the S&P 500 fell 3.23%. No single cause for that one day could be pinned down
The index had been stepping down all September, retesting the low it set in July
Three things overlapped that year: accounting fraud, slowing earnings, and the prospect of war
War is the hardest thing to price. If you do not know whether, when, or how long, all you can add is a discount
The episode low came about ten days later, on 9 October — the final low of the whole dot-com unwind
From the late-May high to the October low the index fell 29.20%
The war itself began in March the following year, and the market rose on it. A case where removing the uncertainty mattered more than the direction

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 put together from the public record; where a specific source was consulted it is listed above.