S&P 500 Shiller P/E at 40.8

Robert Shiller’s cyclically adjusted price-to-earnings ratio, or CAPE, returned to the center of market debate in late May as traders circulated readings around 40 for the S&P 500. YCharts listed the S&P 500 Shiller CAPE ratio at 39.58 for May 2026, up from 38.14 in April and 35.08 a year earlier. Robert Shiller’s Yale data page describes CAPE as a measure built from monthly stock-price, dividend, earnings and consumer-price data dating to 1871. Social-market posts on May 22 cited a higher intramonth reading near 40.8 as investors weighed Nvidia earnings and softer S&P 500 futures. ### What exactly is the Shiller P/E measuring? Robert Shiller’s Yale data page says CAPE uses the current market price divided by the 10-year average of inflation-adjusted earnings. The point of that construction is to smooth out short-term swings in profits that can distort a standard one-year price-to-earnings multiple. YCharts describes the same metric as the S&P 500’s current price divided by the 10-year moving average of inflation-adjusted earnings. (ycharts.com) That makes CAPE a valuation gauge for the broad U.S. equity market rather than a trading signal tied to one quarter’s results. ### Why are people focusing on a reading around 40? YCharts showed a May 2026 reading of 39.58, which places the market near the 40 level that investors often treat as historically elevated territory. (econ.yale.edu) Social commentary on May 22 cited about 40.8, which is directionally consistent with a high-valuation backdrop even if the exact figure depends on timing and data vendor methodology. (ycharts.com) GuruFocus, summarizing the same long-run series, said the median Shiller CAPE value was 16.05 and that the historical record high was 44.2. Those reference points help explain why a reading near 40 draws attention from strategists and retail investors alike. ### Did Nvidia earnings have anything to do with the CAPE number? Nvidia’s earnings did not determine the CAPE ratio, but they shaped the market backdrop in which the number circulated. (ycharts.com) Bloomberg reported on May 21 that U.S. stock futures fell after Nvidia’s results failed to lift sentiment, while another market report said S&P 500 futures slipped 0.1% and Nasdaq 100 futures dropped about 0.3% after the release. (gurufocus.com) May 22 social posts paired that futures reaction with the CAPE reading to argue that investors were confronting both rich valuations and a market still heavily driven by large technology stocks. That link is an inference from concurrent market discussion, not a separate published calculation. ### Why can one source say 39.58 and another say 40.8? (bloomberg.com) YCharts publishes CAPE as a monthly series and listed May 2026 at 39.58. Social-market posts citing 40.8 on May 22 likely reflected an intramonth estimate or a different calculation window based on then-current index levels before month-end data were finalized. Robert Shiller’s own Yale page provides the underlying monthly dataset rather than a live intraday market feed. (news.az) That means third-party services and commentators can show slightly different current readings while still drawing from the same underlying framework. ### Where should readers look if they want to track the next update? Yale’s economics department hosts Shiller’s underlying data series, including the CAPE dataset used by market services. (ycharts.com) YCharts also updates a monthly S&P 500 Shiller CAPE page that showed May 2026 at 39.58 as of this weekend. May month-end updates from data vendors and the next round of index moves will determine whether the market stays near 40 or moves away from it. (econ.yale.edu) Nvidia, the S&P 500 and the data services publishing monthly CAPE figures are the named participants readers will be watching. (ycharts.com)