S&P 500 CAPE Ratio Hits 41, a Level Seen Only During the Dot-Com Era

The Motley Fool·21 Sep 2026·

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Summary · why it matters

The S&P 500's cyclically adjusted price-to-earnings ratio has climbed to 41, a level matched in history only during the dot-com bubble era, when it peaked above 44 in November 1999. The CAPE ratio is up 55% over the past decade, and whenever it has exceeded 40, the S&P 500 has posted a negative annualized total return over the following decade, a pattern tied mainly to the 2000s. The index has generated a total return of 321% over the past 10 years as of Sept. 18, turning a $10,000 investment in a tracking exchange-traded fund into $42,100. Despite the warning signal, the article argues investors should stay the course rather than dump holdings for cash and bonds, noting that similar valuation warnings in the early and mid-2010s preceded a more than fourfold gain in the index over the last decade. It credits structurally different market conditions in 2026, including dominant technology companies growing earnings rapidly, the artificial intelligence build-out, and passive funds controlling more capital than active ones.