Ford (NYSE:F<\/a>) stock is down 4% to $13.87 in Monday mid-morning trading after President Trump announced a sharp escalation in auto tariffs targeting Canadian imports. Meanwhile, Stellantis (NYSE:STLA<\/a>) shares are also down 4% to $5.19, while General Motors (NYSE:GM<\/a>) stock is down 2% to $86.28. <\/p>\n The selling is sorting within Detroit’s Big Three, with Ford and Stellantis taking the harder hit on the tape today. For context, the Global X Autonomous & Electric Vehicles ETF (NASDAQ:DRIV<\/a>) is down 2% to $34.25. <\/p>\n The tariff itself isn’t yet in force, and Trump’s announced 50% duty on Canadian vehicles and parts is set to take effect January 1, 2027, so Monday’s tape is repricing an announced future cost. Ford stock was up 17% year to date through Friday’s close, so today’s slide erodes a slice of that lead. Stellantis has traded well below year-end levels heading in, which magnifies the sting for shareholders already sitting on losses. <\/p>\n Truth Social Post Triggers the Auto Selloff <\/p>\n In a Truth Social post Monday, Trump wrote, “On January first, 2027, tariffs on all cars, trucks, both large and small, automotive parts, and steel, will be increased to 50%.” He accused Canada of “ripping off” the United States and cited a $60 billion trade deficit as justification for the escalation. The post landed at the open of the week and immediately pressured cross-border auto exposure across the Detroit names. <\/p>\n Act now: the analyst who called NVIDIA in 2010 just named his top 10 AI stocks \u2014 and Stellantis didn’t make the cut. Grab the names FREE today<\/a>. <\/p>\n The auto action follows the collapse of U.S.-Canada trade talks late Friday. Separately, Washington applied 50% tariffs to about $20 billion of Canadian goods after talks broke down, 5% of Canada’s exports to the U.S., covering electronics, industrial machinery, dairy, paper goods, appliances, and agricultural equipment. That levy is distinct from the forward-dated auto duty, and Canada announced counter-tariffs scheduled to take effect September 8. <\/p>\n Why Talks Collapsed and Where Automakers Fit <\/p>\n Canada’s ambassador to the U.S., Mark Wiseman, told Bloomberg that Canada “needed medium and heavy duty vehicles to be included” in any tariff relief, noting the issue directly affects General Motors and Ford, both of which operate assembly in Canada. He stated, “That’s just something we could not accept because we want to protect the existence of an automotive assembly industry in Canada for cars, light trucks, you know, medium trucks and heavy-duty trucks.” <\/p>\n Wiseman cautioned that the truck dispute “is not why the deal fell apart,” describing it as one example among several where the written text diverged from what Canada believed it had agreed to. U.S. Trade Representative Jamieson Greer stated Canada sought more “in the last hours,” after Washington had offered to halve steel and aluminum tariffs, substantially reduce auto tariffs, and accommodate Canada on softwood lumber. <\/p>\n Ford and Stellantis are absorbing the announcement more sharply than General Motors on Monday. All three automakers carry cross-border production exposure across cars, light trucks, and heavy-duty units, and the tape is treating that exposure unevenly across the group today. The gap between a 4% drop for Ford and Stellantis and a 2% slide for General Motors is visible on quotes, though no single explanation for the divergence has emerged from either the White House or the companies themselves. <\/p>\n How to Size Risk From Here <\/p>\n The selloff is concentrated within North American auto names. With the auto tariff dated to January 1, 2027, investors have runway to model the impact, and the market is pricing in that risk now. Any softening of the policy, exemptions for USMCA-compliant content, or a resumption of talks could reverse today’s move quickly, while escalation or Canadian retaliation extending beyond the September 8 counter-tariff date could deepen it. <\/p>\n Holders of Ford, Stellantis, and\/or General Motors shares should size their positions to reflect elevated policy risk running into year-end and the January 1 effective date. A cautious approach is warranted for adding exposure here, since headline flow out of Washington and Ottawa can move these names several percent in a single session. Trimming into strength and keeping dry powder for clarity after the September 8 Canadian counter-tariff date can help manage the whipsaw ahead for their portfolios. <\/p>\n Keep an eye on stock-price reactions to any company statements on production impact, guidance revisions, or White House clarification on the scope of the auto tariff. Those disclosures are the next inflection point for Ford, Stellantis, and General Motors shares heading into the fall. <\/p>\n Act now: the analyst who called NVIDIA in 2010 just named his top 10 AI stocks \u2014 and Stellantis didn’t make the cut. Grab the names FREE today<\/a>. <\/p>\n<\/a> 2003 Getty Images \/ Getty Images News via Getty Images <\/p>\n