Current Shiller PE Ratio : 39.79 -0.13 (-0.33%)
Shiller PE ratio for the S&P 500.
Price earnings ratio is based on average inflation-adjusted earnings from the previous 10 years, known as the Cyclically Adjusted PE Ratio (CAPE Ratio), Shiller PE Ratio, or PE 10 — FAQ.
Data courtesy of Robert Shiller from his book, Irrational Exuberance .