"Earnings are going to come through. The U.S. economy is strong," Wien, vice chairman of Blackstone Advisory Partners, said in an interview with " Closing Bell " on Tuesday.
The S&P is currently selling at a little more than 16 times earnings, he said, and he believes it can sell at 20 times earnings.
"The combination of earnings improvement, a little multiple improvement, we can make the 15 percent."
That is just one of his 10 "surprises" for the year, which he called "probable events" with a better than 50 percent chance of happening. It's the 30th year he's compiled the list.
Wien also thinks the Federal Reserve will raise short-term interest rates as soon as March, earlier than many believe.
"I think short rates will go up but I think the yield curve will flatten. There is an abundance of liquidity around the world and my view is that you are going to see long rates pretty much stay where they are," he said.
Wien believes short-term rates will still be attractive and are good for business and housing. In fact, two of his favorable areas for 2015 are housing and capital goods.
When it comes to oil, he expects the decline to continue, with Brent slipping in the $40s. Those low prices are positive for the U.S., India, China and every country that imports oil, he said.
"It's more likely to force Iran to the negotiating table on its weapon's development policy. It's more likely to make Putin more conciliatory on territorial expansion in Ukraine and elsewhere so I see the decline in the price of oil as a net positive," Wien noted.
Also, he said Europe will slip back into a recession, which may not be surprising in and of itself. However, he thinks what will be surprising is that European Central Bank President Mario Draghi will enact a "vigorous" quantitative easing program that won't work.
Click here to see Wien's full list of surprises for 2015.