The USMCA review discussions opened in March 2026, covered in our main piece, centre substantially on rules of origin: the technical standards that determine which goods qualify for duty-free treatment. Understanding how they work, why they matter to Mexico specifically, and how the nearshoring trend of the past several years intersects with the current renegotiation is essential for assessing what the review is likely to produce.
How Rules of Origin Work
Rules of origin in a free trade agreement specify the conditions under which a product qualifies as originating from the agreement's member countries and is therefore eligible for preferential tariff treatment. In USMCA, these rules are structured by product category. The automotive rules are the most complex and economically significant: vehicles must meet Regional Value Content (RVC) thresholds specifying the minimum percentage of value that must originate within the USMCA region, set at 75 percent, up from NAFTA's 62.5 percent, with a separate requirement for labour from workers earning above a minimum threshold wage.
The practical effect is to create a clear boundary between supply chains that benefit from the agreement's preferences and those that do not. A vehicle meeting the RVC and labour value content requirements crosses the US-Mexico border duty-free; one that does not pays the applicable tariff. This commercial incentive to source components from within the USMCA region is precisely the mechanism the agreement's architects intended, and the mechanism the US believes is being circumvented.
Mexico's Structural Position
Mexico has been the primary recipient of the nearshoring investment trend: companies seeking to reduce exposure to US tariffs on Chinese goods and shorten supply chains relocated manufacturing to Mexico, particularly in automotive, electronics, and medical devices. That investment was partly predicated on USMCA preferences and the assumption that production in Mexico would satisfy rules of origin requirements for US market access.
The problem is that some of the manufacturing relocated to Mexico involves significant Chinese component content, particularly in electronics and EV batteries, which is precisely the pattern the US is seeking to address. Mexico therefore faces a negotiating situation in which its most commercially valuable recent investment attraction has partially created the problem the US wants to solve.
This is not a comfortable position, but it is a workable one. The Mexican government's interest is to maintain USMCA duty-free access for genuinely Mexico-based production while demonstrating it is taking the routing concern seriously. That points toward targeted rules of origin adjustments in specific sectors rather than sweeping modifications that would disqualify established operations built under the expectation of USMCA stability.
Where the Nearshoring Story Gets Complicated
Nearshoring to Mexico accelerated significantly between 2020 and 2025, driven by USMCA's implementation, pandemic-era supply chain disruptions, and US-China trade tension. Industrial parks in Monterrey, Saltillo, Juárez, and Tijuana attracted substantial investment, and Mexico overtook China as the US's largest trading partner in 2023.
The USMCA review introduces uncertainty into that story. The most exposed operations are those that rely heavily on imported Asian components and assumed that assembly in Mexico was sufficient for rules of origin compliance. The least exposed are operations that have genuinely regionalised their supply chains, sourcing predominantly from within the USMCA territory. That distinction is what the scoping discussions are ultimately trying to codify.
Frequently Asked Questions (FAQs)
Q: What is Regional Value Content and how is it calculated?
A: Regional Value Content (RVC) is the percentage of a product's total value that must originate within the USMCA region for the product to qualify for preferential tariff treatment. It is calculated using either a transaction value method or a net cost method, as defined in the agreement's rules. For automotive products under USMCA, the RVC requirement is 75 percent, meaning at least 75 percent of a vehicle's value must originate in the US, Mexico, or Canada. This was increased from NAFTA's 62.5 percent threshold.
Q: Why did Mexico become the US's largest trading partner in 2023?
A: Mexico displaced China as the US's largest trading partner in 2023 as a result of nearshoring investment that relocated manufacturing operations to Mexico, combined with the overall increase in Mexico-US trade driven by USMCA preferences and the diversification of US supply chains away from single-country dependence. The shift reflects both genuine manufacturing relocation and the rerouting of some supply chain activity through Mexico to access USMCA duty-free treatment, which is precisely the pattern the current review is examining.
Q: Which sectors in Mexico are most exposed to rules of origin tightening?
A: Electronics manufacturing and electric vehicle battery production are the most exposed sectors, given their high levels of Asian component content. Some automotive assembly operations that source components from non-USMCA suppliers are also exposed, particularly those that have not invested in regional supply chain development. Medical device manufacturing, which has grown significantly in Baja California and other Mexican states, generally has higher domestic and regional content ratios and is less exposed to rules of origin tightening.
Q: How does the labour value content requirement in USMCA work?
A: In addition to the overall Regional Value Content requirement, USMCA includes a High Wage Material and Manufacturing Expenditure requirement for automotive products: a specified percentage of a vehicle's content must come from facilities where workers earn above a minimum hourly wage threshold (currently US$16 per hour). This provision was designed to reduce the wage differential incentive for locating production in Mexico rather than the US or Canada, and it operates as a separate compliance requirement alongside the geographic origin rules.
Q: What happens to nearshoring investment if USMCA rules of origin are significantly tightened?
A: Significant tightening of rules of origin in sectors where nearshoring investment has been concentrated would create compliance costs for operations that cannot quickly regionalise their supply chains. In the most extreme scenario, some operations might lose USMCA duty-free access and face tariffs on their US exports, eroding the competitive rationale for their Mexican location. More likely outcomes involve transition periods that allow companies to adjust sourcing, targeted modifications in high-concern sectors, and grandfather provisions for investment made under the existing rules.
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