Over the last year, the potential fallout of the trade battle surpassed previous worries that troubled these professional investors, such as the chance that the Federal Reserve could tighten interest rates too far or a sharp slowdown in Chinese growth could stifle global growth.

At times this year, the stock market has suffered bouts of extreme volatility, first in May and again last month, when previous cease-fires in the battle between the United States and China broke down.

Data on mutual funds and E.T.F.s has shown money consistently flowing out of the stock market and into the bond market, often considered a safe haven for investors, which is also enjoying a strong year.

Businesses in both the United States and China have begun to express concern about a trade war that has dragged on for more than a year. American manufacturing activity contracted for the first time in three years because of slowing export orders amid the trade dispute, data showed on Wednesday.

Chinese factory activity, meanwhile, contracted for three months this summer before ticking back up slightly in data released this week. Its manufacturing sector has suffered layoffs and factory shutdowns from the trade war and as its economy grows at its slowest pace in three decades.

“When I speak to C.E.O.s of leading Chinese and global companies, everyone is fretting about what the latest escalations mean for their businesses in the short term, and more worrisome, for their long-term strategy and investment plans,” said Fred Hu, founder of the investment firm Primavera Capital Group and former head of Goldman Sachs’s greater China business.

The two sides show little sign of backing down, however. Mr. Trump has gambled that China’s softening economy will put pressure on Beijing’s leaders to back down. Speaking with reporters on Wednesday, Mr. Trump cited the country’s slowdown, which he called, inaccurately, “the worst year they’ve had in 57 years.”