Is the stock market overpriced? Consider that the historical price-to-earnings (P/E) ratio for the S&P 500 over the past 146 years is 15.6. The current earnings multiple is over 25.5 -- more than 63% higher than its historical average value. The problem with using valuation metrics that look in the rearview mirror, though, is that the future is more important than the past for stock market performance.