"The rise in protectionism, pervasive trade policy uncertainty, and slower global growth are considered key downside risks to U.S. economic activity."
About 10 percent of U.S. business economists surveyed believe a recession will begin next year in 2019, while 56 percent believe it will start in 2020.
"This is the first shot across the bow over a trade war," an analyst said.
Expected signals on Trump's on planned global trade and China policies prompted caution from investors.
It is a signal of how Trump plans to elevate a crackdown on competitors in the world market.
Technological change has had a far greater impact on U.S. jobs than any trade deal.