BUZZ-US steel, aluminum cos rise after Trump raises tariffs on steel, aluminum imports

Shares of steel and aluminum manufacturers in the United States rise premarket after President Donald Trump raises tariffs on steel and aluminum imports to a flat 25% "without exceptions or exemptions"

United States Steel X.N up 1%, Nucor NUE.N and Steel Dynamics STLD.O rise more than 2% in premarket trade

Roughly a quarter of all steel used in the U.S. is imported, mostly from neighbors Mexico and Canada or close allies in Asia and Europe like Japan, South Korea and Germany

Aluminum companies Century Aluminum CENX.O and Alcoa AA.N up more than 1% premarket

Roughly half all aluminum used in the U.S. is imported, with the vast majority coming from Canada