S&P 500 Shiller CAPE Holds Above 40 Since May, Echoing 1999 Bubble Warning
Updated
Updated · Yahoo Finance · Aug 29
S&P 500 Shiller CAPE Holds Above 40 Since May, Echoing 1999 Bubble Warning
3 articles · Updated · Yahoo Finance · Aug 29
Summary
The S&P 500's Shiller CAPE ratio has stayed above 40 since early May 2026, a rare stretch that points to historically rich valuations and a higher risk of volatility.
That matters because the CAPE ratio has averaged about 17 since the 1870s, while the last comparable move into the 40s came during the dot-com bubble.
In 1999, the measure peaked above 44 in December, roughly four months before the tech bubble burst, making the current reading a closely watched warning sign.
AI-driven gains have helped push the S&P 500, Nasdaq and Dow to repeated record highs, but the report says elevated valuations alone do not mean investors should exit the market.