A trader works on the floor of the New York Stock Exchange.

The following is a free preview of CNBC Pro. To get more investment analysis and the live CNBC TV feed, please subscribe.

The U.S. stock market will drop by 10 percent at some point during the next five months, pulling the S&P 500 lower to 1,900, Stifel strategist Barry Bannister wrote in a note to clients.