US Import Tariffs from Mexico

USMCA rules of origin determine whether Mexican-manufactured goods qualify for 0% preferential duty rates vs. full MFN rates. The primary methods: (1) Tariff classification change (tariff shift) — the finished product's HTS code must differ from its non-USMCA inputs at the chapter (2-digit), heading (4-digit), or subheading (6-digit) level depending on the product-specific rule, (2) Regional value content (RVC) — typically 60%–65% of the goods value must be USMCA-region content under the transaction value method, or 50%–55% under net cost method. For most manufactured goods, either method may be used. Complex goods (electronics, chemicals) may have additional requirements. Importers must obtain USMCA certifications from Mexican suppliers before filing first entry and update them for any supply chain changes.

Maquiladoras are Mexican manufacturing operations (formally IMMEX — Industria Manufacturera, Maquiladora y de Servicios de Exportación) that allow duty-free temporary import of US inputs for manufacturing and subsequent re-export to the US. Under USMCA, maquiladora goods are evaluated under normal USMCA rules of origin — the IMMEX program affects Mexican domestic tax treatment but does not automatically grant USMCA origin. Key USMCA consideration: if a maquiladora uses non-USMCA inputs (Asian components, for example), the finished product may not meet USMCA tariff shift or RVC requirements. Importers should verify USMCA compliance separately from Mexican IMMEX program status.

Mexico, like Canada, was exempted from Section 232 steel and aluminum tariffs under a joint agreement (effective May 2019). Mexican steel and aluminum imports currently enter the US without Section 232 surcharges — the 25% steel and 10% aluminum tariffs do not apply to Mexico-origin goods. The exemption replaced the original Section 232 tariffs imposed in 2018. The arrangement includes safeguard mechanisms allowing the US to reinstate tariffs if import volumes surge or if goods are found to be transshipped. Some steel products with significant third-country (non-USMCA) content may not qualify for the Section 232 exemption.

Mexico is the US's largest supplier of vehicles and auto parts. USMCA automotive rules require: (1) 75% RVC for passenger vehicles — manufacturers have until 2027 for full phase-in, (2) 70% North American steel/aluminum content by weight, (3) 40% labor value content from $16+/hour workers (Mexico phased in: 38% by 2024, 40% by 2025). Mexico has been a key location for high-volume auto parts production — wire harnesses, engine parts, seat assemblies. For auto parts, RVC requirements range 65%–75% depending on part category. Non-qualifying vehicles face 2.5% MFN duty; non-qualifying light trucks face 25% MFN duty. Verify ROO certifications annually from Mexican auto suppliers.

CBP has increased enforcement against goods manufactured in China being transshipped through Mexico to avoid Section 301 tariffs. Common schemes: components shipped from China → assembled in Mexico → exported to US as "Mexico-origin." CBP requires genuine substantial transformation in Mexico, not mere assembly or minimal processing. Enforcement tools: CBP origin verification visits to Mexican facilities, review of bills of materials and production records, CF-28/29 requests during entry review. Importers sourcing from Mexico should conduct supplier due diligence: obtain factory audit reports, verify Chinese input percentages in BOMs, ensure Mexican manufacturing adds genuine value. Penalties for origin fraud include seizure, reliquidation at Section 301 rates, and potential criminal referral.