According to a recent report, the PE ratio of the
S&P 500 has risen to 16, a 14 percent increase relative to earnings over the last 12 months. The last time the PE ratio has risen this fast was 1999, just prior to the dot com crash.
The S&P 500 PE has averaged 17.4 during bull markets since 1957, and
have typically reached a high of 20.2 at the top of the market, with a
high of 31 times in March 2000.