S&P 500 Shiller CAPE Hits 40 for 2nd Time in 155 Years
Updated
Updated · Yahoo Finance · Aug 23
S&P 500 Shiller CAPE Hits 40 for 2nd Time in 155 Years
3 articles · Updated · Yahoo Finance · Aug 23
Summary
June 2026 marked the second time since 1871 that the S&P 500 Shiller CAPE ratio reached 40, a level previously seen only during the 1999-2000 dot-com bubble.
The valuation gauge compares stock prices with a 10-year average of inflation-adjusted earnings, and the latest jump reflects share prices rising much faster than underlying profits.
Shiller's data show the CAPE ratio stayed below 25 for most of market history and averaged about 15.7 from 1871 through 2000, underscoring how extreme the current reading is.
History gives the signal a troubling backdrop: after the CAPE ratio first broke 30 in 1929, the U.S. market crashed, and elevated readings have often preceded weak returns or major drawdowns.
With the CAPE ratio hitting 40, are we facing a devastating 1999-style crash or entering a fundamentally new AI-driven financial era?
Does a backward-looking valuation metric still matter when an unprecedented AI productivity boom is rapidly rewriting the rules of corporate earnings?
The S&P 500’s Record-High CAPE Ratio in 2026: AI-Driven Valuations and the Lessons of Market History
Overview
In August 2026, the S&P 500 Shiller CAPE Ratio soared to 41.58, driven by massive AI capital spending from tech giants like Alphabet and Microsoft. This surge in investment fueled strong earnings growth, especially in technology, and helped lower the forward P/E ratio even as valuations remained high. Calmer Middle East tensions and falling oil prices eased inflation worries, reducing borrowing costs for companies. However, the market’s elevated state echoes past bubbles, such as 1929 and 1999, and is complicated by structural changes like new accounting rules and a shift toward high-margin tech firms. As a result, traditional portfolio strategies face new risks, making diversification and rebalancing more important than ever.