The price-to-earnings ratio for the S&P 500, based on the last four quarters of net earnings, now sits at 22.5, up from 18.9 at the close of the fourth quarter. That multiple stands well above the average of 19 for the last two decades, not to mention the reading of around 16 over the past century......Shiller's adjusted P/E right now? 31. It's only been that lofty twice, just before the 1929 market crash, and in the run-up to the dot.com bubble in 2000. The Shiller P/E's message: High multiples on top of inflated profits equals low future returns.