September was not a good month for the stock market. The S&P 500 (^GSPC +0.73%) index dropped 0.3% for the month. The total U.S. stock market, as measured by the Vanguard Morningstar Total Stock Market ETF (VTI +0.75%), fell 0.8%.
The results aren't a big surprise, as September has historically been a rough month for stocks.
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What might have been a little surprising to some investors was that September turned out to be a poor month for almost all asset classes. Foreign stocks were down in both emerging and developed economies. Bonds of every sort were down, as global yields soared. And real estate suffered during the month, with the Vanguard Real Estate Index Fund ETF (VNQ +0.37%) fell 6.2%, its worst monthly performance in almost two years.
Real estate investment trusts (REITs) and other real estate-related stocks are suffering from rising interest rates and bond yields, which make REIT borrowing more expensive and push mortgage rates higher, damaging the housing market.
Two asset classes gained in September
So, did any asset classes make gains during the month?
Yes, two did: commodities and cash. Commodities returned 4.5% in September, as measured by the iShares S&P GSCI Commodity-Indexed Trust (GSG -0.86%). That ETF tracks the S&P Dow Jones GSCI index, which is heavily concentrated in energy commodities.
Part of its impressive return for the month stems from crude oil rising 8.9% in September amid the ongoing conflict in the Persian Gulf. As I write this, Brent crude, the international benchmark, is trading at around $101 a barrel.
NYSEMKT: GSG
Key Data Points
Not all commodities gained. Gold was down 6.8% in September due to a stronger dollar and higher bond yields, which rendered the yellow metal less attractive to investors.
Cash was up for the month, as measured by the iShares 0-1 Year Treasury Bond ETF (SHV +0.02%), which includes U.S. Treasury bonds with maturities of a year or less. It's not literal cash but functions as a low-risk cash equivalent.
While equities overall didn't perform well in September, a slice of the stock market did. The Nasdaq-100 was up 3.3%. That index tracks the 100 largest nonfinancial companies listed on the Nasdaq stock exchange, and it's mostly made up of large technology and software companies. And many of those, including Meta Platforms, Dell Technologies, and Advanced Micro Devices, posted gains of more than 20% during the month.
The Nasdaq-100 has climbed almost 21% so far in 2026, outpacing the S&P 500, which is up 12.7% this year.
Many of the trends that affected the market in September look likely to continue into October. The war in the Persian Gulf doesn't seem likely to be resolved any time soon, while bond yields remain elevated and the Federal Reserve looks to be on a path to higher interest rates.
