Stocks, while inexpensive, could still have farther to fall, Blackstone Advisory Partners Vice Chairman Byron Wien said Wednesday.
"You know, the stock market is not expensive. The price-earnings ratio of the market is very reasonable right now," he said. "I think the market has further to go on the downside."
On CNBC's "Fast Money," Wien added that stocks weren't necessarily predictable.
"The market always has a tendency to go farther than you think, up and down," he said. "And I think the correction could be greater than 5 percent."
Wien laid out his case for where he saw stocks headed for the remainder of 2013.
"My concern about the second half is that the economy isn't building the kind of momentum that everybody thought," he said. "When the stock market was doing well and it looked like the economy was going to pick up, there were a lot of people who thought economic growth was going to go to 3 percent real. I don't think that's likely. I think we could have another couple of quarters at 2 percent."
Looking at the amount of quantitative easing from the Federal Reserve, Wien noted that its balance sheet in 2008 was $1 trillion.
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"At $85 billion a month, they're going to put $1 trillion in this year. And they can't get the economy to grow at 2 percent in the first half," he said. "I don't think the monetary expansion is having the impact."
Wien saw a narrow effect of the Fed's asset purchases.