Investors are cautious at a key moment for equities under President Donald Trump.
Those who have furiously bid up equities may have the most on the line.
Consecutive gains in the Dow Jones Industrial Average have left it at the doorstep of history.
For one, U.S. stocks will surge 12 percent this year, says Wien, the 83-year-old former Morgan Stanley strategist.
Optimism is higher than ever on a group of stocks that have specialized in disappointment.
The S&P 500 index masks a weakness in breadth that has spelled trouble in the past.