S&P 500’s Shiller P/E climbs to 41.3, nearing dot-com peak levels

The S&P 500’s Shiller price-earnings ratio has risen to 41.3, close to the 44.2 peak reached in December 1999 and far above the roughly 19 average over the past century. Because it uses 10 years of inflation-adjusted earnings, the measure smooths out short-term profit bursts tied to surging AI-related capital spending. By contrast, the index’s forward P/E is about 21 times expected earnings, only modestly above its 30-year average of 17.1. A key caveat is that much of the profit growth is concentrated in a small number of mega-cap technology companies, complicating what the valuation signal means for the broader market.