Widely followed investor Byron Wien says stocks have become overextended as they hit record highs, and he predicts a significant decline for the market in the months ahead.
"I think this is going to be a down year for the market. … I think it's going to struggle in the second half," the vice chairman at Blackstone Advisory Partners said Wednesday on CNBC's "Trading Nation."
Since the S&P 500 has risen 6.3 percent through Wednesday's close, that would represent a substantial loss for investors who are buying stocks now, as indexes hit all-time highs.
Wien's concerns come down to nothing more frightening than valuation levels that appear extended over historical averages.
"I don't think we're going to have a bear market," Wien said. "I just think the market is very fully priced, and we could have a pullback from current levels."
This is in line with a prediction made at the beginning of the year, when he foresaw that U.S. equities would suffer "a down year."
When he zooms out, Wien observes that companies have a lot of cash piled up on their balance sheets, and even with 2 percent economic growth, "I think companies will find a way to make money in that environment. So long-term, I'm positive about equities."
"But they're a little ahead of themselves now," he added.