The S&P 500 fell 0.74%, while the Nasdaq Composite fell 0.68%. The Dow Jones Industrial Average fell 293.12 points, or 0.63%.

LPL chief technical strategist Adam Turnquist is worried the stock market is relying too much on the AI trade to carry it.

“While the trend model shows that there are still more S&P 500 stocks trading in uptrends vs. downtrends, the narrowing gap highlights emerging cracks in the market’s foundation,” Turnquist said in a Wednesday note to clients. “These cracks can be repaired through broadening participation, but they also underscore the elevated concentration risk tied to a handful of dominant names driving the rally.”

President Donald Trump last week threatened to place an additional 100% tariff on any goods coming from China in response to the country’s new export controls on rare earth minerals. The trade tone softened over subsequent days, but tensions increased again Tuesday, when Trump on  threatened China with a cooking oil trade ban.

Investors are also keeping a watchful eye as the U.S. government shutdown continues for a third week. The stoppage has led to an indefinite shutdown of crucial economic data releases from federal agencies, giving traders less information at a time when concerns about the labor market, the effect of tariffs on consumers, high interest rates and historically elevated market valuations all remain top of mind.