According to this Bloomberg article, Ben Graham would still find US stocks to be expensive:

Benjamin Graham, the father of value investing and mentor of Warren Buffett, would find most U.S. stocks expensive even after the Standard & Poor’s 500 Index dropped 56 percent in 17 months.

Mr. Graham’s valuation method measured stocks against a decade of earnings to “smooth out distortions. Interesting, but I’m not sure if I understand the impact of it:

Graham measured equities against a decade of profits to smooth out distortions, a method that shows the S&P 500 trading at 13.2 times earnings, according to data compiled by Yale University Professor Robert Shiller. At the bottom of the three worst recessions since 1929, the average ratio fell below 10. To reach that level, the S&P 500 would sink another 27 percent.

Take it with a grain of salt, but it is interesting to see how valuation methods have changed over time.

Another interesting snippet from the Bloomberg piece:

“A lot of earnings estimates on which the market valuations are based are quite suspect,” said John Carey, who oversees $8 billion at Pioneer Investment Management in Boston. “You have to adjust what you see out there for reality. I remember thinking that a stock selling at 10 times earnings was expensive” in the 1970s and 1980s, he said.