Does S&P Stand for SPooky During October?

Darin Newsom

Sat, October 3, 2026 at 10:28 AM EDT

• The month of October has a list of memorable down days, leading to the legend it is a bearish moth for the S&P 500.

• However, October also has a number of the largest daily rallies.

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• Seasonally, the most bearish month for the S&P 500 is not October, but rather September. Myth Busted.

One of the many things that happened this past week was the calendar changed from September to October, not only marking the beginning of Spooky Season (with all Hallows Eve waiting at the end of the month, though given the continued situation in the United States, every season could be considered Spooky Season) but also the end of the financial third quarter (Q3). There are many scary myths surrounding the month of October – The Legend of Sleepy Hollow anyone? – including it is a bearish month for the S&P 500 (($INX).

Like most myths, this one is seeded by scary stories. I asked Barchart’s AI analyst CARL for a list of largest daily moves, and on the downside we have days remember by titles:

• Black Monday, October 19, 1987 (a special time for me)

  • With the highlight being “computerized program trading cascade

  • A precursor to Watson running amok these days

• Black Monday, this one from October 28, 1929)

  • “Margin call liquidations; start of the Great Crash (a dual nickname October day)

• Black Tuesday, from October 29, 1929, the day after the Black Monday (obviously before Turnaround Tuesday was a thing)

  • “Panic selling with record volume”

Looking at the Top 10 list of largest losses we see October filling 5 of the spots, with a clean sweep of the podium disrupted by March 16, 2020 – the COVID-19 pandemic panic (“emergency Fed rate cut to zero backfired”; something the current US president (who happened to also hold the title in March 2020) should pay attention to). Given this, it seems a lock the most bearish month for the S&P 500, from a seasonal analysis point of view, is October, right? In the words of legendary US college football talker (another big part of October in the US, while the rest of the world shakes its head in befuddlement) Lee Corso, “Not so fast my friend”.

I also asked CARL for the 10 days with largest gains, and the list came back with 4 dates in October: