Eastern time, the S&P 500 was 0.1% lower, the Dow Jones Industrial Average was down 0.5%, and the Nasdaq Composite rose 0.2%.

Wall Street's main indexes dipped on Monday after President Donald Trump said he plans to double tariffs on imported steel and aluminum, fueling more uncertainty around U.S. trade policies. Trump said late on Friday he planned to increase tariffs on imported steel and aluminum to 50% from 25% starting Wednesday,

Wall Street opens lower as tariffs double on steel and aluminum, impacting major indexes like the Dow and S&P 500.