Why Stocks Went Up in September Even Though Most Stocks Didn't
The S&P 500 and Nasdaq rose on September 30, 2026, after a lower-than-expected inflation report calmed fears about high interest rates from the Federal Reserve. Both were headed for gains in September. Reuters
A day earlier, most stocks were not joining in. On September 29, 2026, the S&P 500 had 8 stocks at a fresh yearly high and 33 at a fresh yearly low, Reuters reported. The Nasdaq had 34 new highs and 244 new lows. Lows beat highs on both. Reuters
The same was true a week before. On September 24, 2026, the S&P 500 had 14 new highs and 41 new lows, and the Nasdaq had 53 new highs and 238 new lows, Reuters reported. Reuters
In the middle of the month, results were mixed. On September 18, 2026, the Dow fell 0.18%, the S&P 500 rose 0.17%, and the Nasdaq rose 0.40%, Reuters reported. Reuters
September 11, 2026 was stronger. The S&P 500 rose 0.86% to finish at 7,656.98, and the Nasdaq rose 0.96% to finish at 26,333.04. Reuters
That would add to a long winning streak. The S&P 500 has not risen by 10% or more four years straight since before the early-2000s dot-com bust. Yahoo Finance
The broader context here is simple. A few big companies can pull the average up even when most stocks are down. It is like a class average raised by a few top scores.
In my view, cool inflation helps mainly by taking pressure off interest rates. Lower rate fears support stock prices, especially for big growth companies. One good report does not mean every stock recovers.
Looking at what this means for positioning, September rewarded a narrow group of leaders. Protection tied to the whole index may not help if you own the laggards. For savers and borrowers, the link is rates. Until more stocks join in, prices can swing fast on the next inflation news.
