General Motors has lowered its earnings forecast for 2025 as it braces for up to $5 billion in potential tariff-related costs, signaling renewed concern over trade policy volatility under the Trump administration.The move comes days after President Donald Trump announced executive orders to ease some existing 25 percent tariffs on automobiles and auto parts, while leaving broader tariff threats in place.The automaker said its initial guidance for 2025, issued earlier this year, did not include the impact of prospective auto import duties. GM now projects full-year adjusted earnings before interest and taxes (EBIT) to be between $10 billion and $12.5 billion, down sharply from its previous forecast of $13.7 billion to $15.7 billion.The revised outlook incorporates an estimated tariff exposure ranging from $4 billion to $5 billion. Shares of the company rose over 2 percent in premarket trading following the announcement.Why It MattersThe revised forecast reflects growing uncertainty for U.S. automakers as the federal government reconsiders its trade posture. While Trump's latest executive actions roll back portions of his original 25 percent auto tariffs, analysts and executives alike are grappling with the broader implications of a more aggressive tariff regime.What To KnowTrump's latest executive order partially reversed tariffs originally imposed during his first term, but left open the possibility of more sweeping trade actions in 2025. These measures are framed by the administration as incentives for companies to increase U.S.-based production, though critics argue they risk higher consumer costs and economic drag.What People Are SayingIn a shareholder letter Thursday, GM CEO Mary Barra said: "As you know, there are ongoing discussions with key trade partners that may also have an impact."We will continue to be nimble and disciplined and update you as we know more."Donald Trump has defended the revised policy shift as a necessary step toward reshoring manufacturing. "We're putting America first," he said at a press conference earlier this week.What's NextThe auto industry will be watching closely as trade negotiations unfold and more clarity emerges on which imports may be subject to duties. GM has indicated it may revise guidance again depending on how those talks evolve.For now, the lowered forecast represents a concrete cost of uncertainty. Investors and competitors are likely to follow GM's lead as they reevaluate their own financial projections and supply strategies for the year ahead.