Since 1950, Only Two Months Have Averaged a Loss on the S&P 500. September Is the Ugly One.

Wall Street’s worst calendar month just started — and this year, the setup is especially rough.

Avg. S&P 500 Return by Month (1950–2025)

November

+1.69%

December

+1.55%

April

+1.46%

July

+1.28%

March

+1.13%

January

+1.07%

February

−0.03%

September

−0.70%

Top 6 positive months shown, plus both negatives. February is essentially flat. September is the real outlier.

Source: S&P Dow Jones Indices / Barchart, 1950–2025

Yesterday was the first trading day of September. The S&P 500 dropped 0.7%. The Nasdaq fell more than 1%. Oil surged past $90 on the Iran situation, bonds sold off around the world, and traders started pricing in a 65%–68% chance the Fed raises rates this month.

Rough start. But here’s what nobody on CNBC mentioned...

September has been doing this for 75 years.

Look at the chart. Since 1950, ten of twelve months have averaged a positive return for the S&P 500. February is essentially flat, at −0.03%. And then there’s September — a real, meaningful loss of about 0.7% on average. It’s the only month that reliably costs investors money. Since 1950, it’s finished in the green just 44% of the time. No other month has a sub-50% hit rate; February’s 54% is a distant second.

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Chart of the Day — September 2, 2026

Most people hear “September is bad for stocks” and file it under Wall Street folklore. Like the Super Bowl indicator or the hemline index. Something cute but useless. It’s not. This pattern has survived 75 years of data — through wars, recessions, bubbles, and crashes. Under fourteen presidents and more Fed chairs than I can name without looking it up. And if anything, it’s gotten worse recently: over the last ten years, September has averaged −1.6% with just a 50% win rate.

And this particular September comes loaded. WTI crude above $90 for the first time in over a month. The 10-year Treasury yield near 4.79%. Traders betting roughly two-to-one the Fed hikes rates, not holds. That’s the kind of cocktail that turns an average bad September into a really bad one.

But here’s what I’d tell you over a steak... don’t sell. The same data that says September is the worst month says November through January is the strongest three-month window of the year — averaging about +4.4%, and finishing positive 80% of the time. The guys who panic in September and sit on the sidelines until everything “feels safe” miss that ride. Over a decade, that’s serious money left on the table.

The Takeaway

“September is the only month that reliably loses money for S&P 500 investors — about −0.7% on average since 1950, and worse over the last decade. It’s been that way through every war, crash, and boom in between.”

If your portfolio takes a hit this month, remember what comes after. November alone averages +1.69% — the best month of the year. The guys who sell in September and miss November are the ones who look back and wonder where their returns went. That’s worth keeping in mind before you make any moves this month.

More tomorrow. Stay sharp.

— Ray Calloway

"September Is Bad for Stocks" Sounds Like Folklore. The 75-Year Record Says Otherwise.

Since 1950, Only Two Months Have Averaged a Loss on the S&P 500. September Is the Ugly One.

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