Reuters via Der Spiegel:
I am not yet sounding the alarm. But in many countries stock exchanges are at a high level and prices have risen sharply in some property markets," Shiller told Sunday's Der Spiegel magazine. "That could end badly," he said.
"I am most worried about the boom in the U.S. stock market. Also because our economy is still weak and vulnerable," he said, describing the financial and technology sectors as overvalued.
Shiller: The current adjusted price/earnings of 25 is quite a bit above the average, which is about 16. But it's not so much above average that I would disqualify stocks as an investment...
But I'm starting to get more worried about the market as it keeps going up. When CAPE gets as high as 28, stocks would start to look unattractive.
My valuation-confidence index, which measures the confidence that the market is not overvalued, was at its all-time low right at the peak of the market in 2000, and we are not anywhere near down there. For individual investors, it was recently at a little over 56, versus 27 in April 2000. So I don't see the same bubble-like mentality right now