Don't expect a significant boost to stocks if and when the U.S. and China strike a deal on trade, Morgan Stanley CEO James Gorman said Friday.

Stopping the trade spat from turning into a true trade war "is clearly a positive. I think the market would rally on the news of that," Gorman said during an interview at the Council on Foreign Relations. But "would it be a meaningful rally? I'd be very surprised."

Gorman made his comments after President Donald Trump told reporters earlier in the day that he thinks a "very big spike" will take place in the stock market once a trade deal is reached.

Stocks are up sharply this year in part because of increasing expectations for a U.S.-China trade deal. Since the start of the year, the is up more than 8 percent.