Mexico Faces New Tariff Round as 301 Probe Nears Close

Mexico faces a pending US Section 301 determination on structural excess manufacturing capacity, a probe covering 16 economies that could result in new tariffs as early as August 2026, layered atop the forced-labor duties already replacing prior emergency-powers tariffs. Automotive, machinery, computing, industrial equipment, and medical device sectors face the greatest exposure, while roughly 85% of Mexican exports remain shielded under USMCA rules of origin. The outcome will shape Mexico's negotiating position heading into the next phase of the USMCA joint review.

Mexico faces another round of tariff negotiations with Washington as soon as August, Economy Minister Marcelo Ebrard warned, pointing to a pending US investigation into "excess manufacturing capacity" that could add fresh duties on top of measures already in place. 

Ebrard said the immediate priority is to learn the outcome of the Section 301 probe being carried out by the Office of the US Trade Representative (USTR) before any further negotiation can move forward.

US Trade Representative Jamieson Greer confirmed separately that Mexico remains one of 16 trading partners under review in the excess-capacity inquiry, opened under Section 301 of the Trade Act of 1974. "We are going to finish that investigation, hopefully soon, and we will make a proposal," Greer said, declining to rule out that the process ends in new tariffs for the countries involved, Mexico among them.

A Third 301 Case in Months

The excess-capacity investigation is one of two parallel Section 301 actions the USTR opened in March 2026 to justify additional tariffs on the bulk of US imports. The first targets alleged failures by 60 trading partners to block goods made with forced labor; the second examines whether 16 economies, including China, the European Union, Japan, India, South Korea, Vietnam and Mexico, carry structural overcapacity in manufacturing that distorts US trade. 

Mexico Business News has tracked the forced-labor track closely: in June, USTR proposed an additional 10% tariff on Mexican goods tied to that investigation, and by early July, Mexico joined Peru, Guatemala and Ecuador in petitioning USTR for an exemption at public hearings, arguing the duty was never designed with USMCA partners in mind.

That forced-labor tariff has since taken effect as a replacement, not an addition, to the emergency-powers surcharge Mexico had faced since April. Ebrard said last week that the new 10% rate under Section 301 simply substitutes the 10% previously applied under Section 122, meaning the tariff treatment for Mexican exporters is unchanged in practice. Crucially, USMCA-compliant goods, roughly 85% of Mexico's exports to the United States, remain exempt from the new duty. 

USTR finalized the forced-labor determinations across 60 economies earlier this month, with Mexico assigned the lower 10% rate while 46 other economies were assigned 12.5%.

Excess Capacity: the Open Front

Unlike the forced-labor case, the excess-capacity investigation has no resolution yet. The USTR closed public comments on April 15, 2026, and held hearings from May 5 to May 8, but has not issued findings or proposed any specific action. The agency defines "structural excess capacity" as industrial production capacity sustained through government intervention that leaves other countries running large or persistent trade surpluses, displacing US output.

Mexico has pushed back hard on being included at all. In May, Economy Ministry formally petitioned USTR to remove Mexico from the excess-capacity probe, citing 213,000 combined job losses on both sides of the border as evidence that Mexican and US manufacturing are integrated rather than competing. 

Mexico's private sector made the same case in person: business chambers CCE, CONCAMIN and INDEX told USTR directly during the second round of USMCA review talks that no evidence supports classifying Mexican production as overcapacity, warning that an adverse finding would strain integrated North American supply chains in automotive, plastics and machinery.

Why it Matters Now

The stakes go beyond the excess-capacity case itself. Analysts at Ansley Consultores note it remains unclear which Mexican manufacturing sectors would be targeted if USTR rules against Mexico, but flag automotive, machinery, computers, industrial equipment and medical devices as the sectors most exposed given prior US actions against countries running sector-specific surpluses.

The timing compounds the uncertainty. Mexico is simultaneously navigating the formal USMCA joint review, where Section 232 tariffs of up to 50% on steel and aluminum and 25% on automobiles remain unresolved and have already cut steel exports by more than a third. Ebrard said Mexico intends to reach September "with all the elements on the table" before continuing talks with USTR, an implicit acknowledgment that the excess-capacity ruling could still land before, or alongside, the next stage of USMCA negotiations.

For now, Mexico's argument rests on the same figure Ebrard has repeated throughout 2026: with roughly 85% of exports entering the US duty-free under USMCA rules of origin, Mexico enters any new tariff round in a stronger position than most of the 16 economies named in the excess-capacity investigation. Whether that cushion holds will depend on findings USTR has yet to publish.