The S&P 500 (SNPINDEX:^GSPC) closed September at 7,651.54 and October at 7,580.07. That’s two monthly losses in a row, of around 0.5% and 0.9%, and the first time since 2023 that the index has dipped in both months.
October’s loss came late. Heading into its last session, the index was up around 0.9% for the month, and a fall of about 1.8% on Oct. 30 sent it under September’s close. Yet the S&P 500 has risen around 11% this year and finished October within about 3% of the record it set on Oct. 6.
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I wanted to see what has usually come next. With month-end closes (price only, no dividends), I found 16 past years since 1950 when the index dropped in both months. That comes to around one year in five.
Image source: Getty Images.
The 16 cases
Most of these years finished well. The index rose over November and December in 12 of the 16, and the median two-month gain was around 3.7%. The four that didn’t were 1957, 1987, 2000, and 2008.
The next 12 months looked even better. A year after the end of October, the S&P 500 was higher in 14 of the 16, and the typical gain was around 13%. Of course, two of these gains hardly counted, at about 0.1% after 1952 and 0.9% after 1977.
The two losses were in 1989 and 2000.
In 1989, the index had already climbed around 23% for the year through October. The next 12 months ran into a recession that started in August 1990, according to the National Bureau of Economic Research, and the S&P 500 finished that stretch down about 11%. In 2000, the index had peaked back in March, early in the dot-com bust, and it dropped around 26% over the next year.
Two down months didn’t shift the odds much
This record looks a lot like a normal year’s.
From 1950 through 2025, the index gained over November and December in 59 of 76 years, or around 78% of the time, and the typical rise was about 3.6%. After a down September and October, the rate was 75%, with a typical rise of around 3.7%. So two losing months haven’t said much about how the year finishes.
The 12-month results look a bit more favorable — 14 of 16, versus 60 of the 75 years from 1950 through 2024. But with just 16 cases, a gap that small could easily come down to luck.
And the starting year matters. Yahoo Finance’s data for the index goes back to the end of 1927, and the years before 1950 have eight more September-October drops, mostly in the Great Depression.
