The U.S. auto industry may be staring down a massive profitability crunch as President-elect Donald Trump's proposed 25% tariffs on vehicle imports from Mexico and Canada threaten to squeeze margins by nearly one-fifth, according to S&P Global Ratings.

Michigan-based automakers like General Motors Company (NYSE:GM), Stellantis N.V. (NYSE:STLA), and Ford Motor Co. (NYSE:F) could lose up to 17% of their combined annual EBITDA – a financial acronym that stands for earnings before interest, taxes, depreciation, and amortization – in a worst-case scenario. That's according to a note published Friday by S...