S&P 500 Flashes Rare Valuation Warning Not Seen Since 1890

On July 12 2026, fresh market commentary warned that the S&P 500 Shiller CAPE ratio has reached levels near 41.4, flashing a valuation signal observed only once since 1890. The metric, more than double its long-term average, sits close to the 44.19 peak recorded during the dot-com bubble in December 1999. Both articles highlight how six prior instances of CAPE above 30 were followed by major declines, though they also note the current AI-driven bull market that began in October 2022 remains the ninth-longest in history. Investors are urged to reassess concentration risk and consider diversification amid elevated downside potential.