After a 10.1% average since 1926, strategists see tougher S&P 500 returns ahead

U.S. stocks delivered an average 10.1% annual return from 1926 through 2025, outpacing Treasurys (3.3%) and roughly 3% inflation. But strategists cite high valuations and heavy concentration in a few mega-cap tech names, with Research Affiliates projecting just over 3% annualized for the S&P 500 over the next 10 years. They say diversification—potentially beyond a market-cap weighted S&P 500 approach—could matter more for investors with shorter time horizons.