Trade talks between the U.S. and Canada collapsed in the 11th hour Friday, renewing fears of an all-out trade war as new tariffs went into effect over the weekend.

Ford and Stellantis shares slipped Monday after President Trump announced a 50% tariff on automobiles and auto parts from Canada come January. Ford shares fell about 4% in midday trading, while Stellantis saw a 4.8% decline. General Motors shares were down about 1.7%.

Meanwhile, U.S. steel producers saw modest gains. Cleveland-Cliffs saw the largest move, up 4.8%. Nucor and Steel Dynamics rose about 2%.

Though steel wasn't explicitly named in the initial tariff rollouts, its inclusion in retaliatory lists pushed the U.S. and Canada into the now defunct trade talks. These retaliatory tariffs on steel and aluminum are back on the table.