The stock market is beginning to sense headwinds unrelated to quantitative easing, Blackstone Advisory Vice Chairman Byron Wien told CNBC.
"I think while valuations are still fair, I think the market's made a lot of progress, and I think there's some trouble ahead," he said.
"The trouble is that profit margins, in my opinion, have peaked and that earnings are going to be disappointing in the second half, and that's what the market is beginning to sense."
