Stock prices have surged, leading to high valuations. Historical data suggests negative returns when S&P 500 forward P/E ratio exceeds 23. Analysts predict rough decade ahead for U.S. stocks. However, projections based on limited sample size may not be accurate. Base rate indicates average S&P 500 returns of 10.6% over 100 years. Investors advised to consider valuations before making decisions.

Read more at Yahoo Finance: The S&P 500 Just Did Something Seen Only Twice in the Last 45 Years. Here’s What History Says Happens Next and Why You Should Take It With a Grain of Salt.