. However, originating auto parts that meet T-MEC rules maintain preferential treatment. Mexico also practically maintained its light vehicle production volume and increased its exports during the semester.

San Luis Potosí Auto Parts Exports Fell During the Six Months

According to Data México, a platform of the Ministry of Economy, Potosi exports registered an annual decline of 6.9% between the first half of 2026 and the same period last year. The decline equates to $79.7 million less in auto parts:

Source: Data México, Ministry of Economy. San Luis Potosí exports corresponding to HS code 8708, “Parts and accessories of motor vehicles.” Figures in millions of dollars.

January recorded the largest contraction, with an annual reduction of 18.1%. Although the difference narrowed to 1.2% in June, none of the six months exceeded the value observed a year prior. The analysis considered HS code 8708, corresponding to parts and accessories for motor vehicles under headings 8701 to 8705. This category includes:

• Body parts and fenders.
• Brakes and their components.
• Gearboxes and transmission parts.
• Axles and suspension systems.
• Steering systems.
• Wheels and their components.
• Other specific accessories for vehicles.

HS code 8708 represents one of the main categories in auto parts trade. However, it does not encompass the entire automotive supply chain. Products such as tires, batteries, engines, safety glass, harnesses, seats, and electronic components are registered under other headings. Therefore, the 6.9% decrease exclusively corresponds to the products included in the analyzed classification.

Did Potosi Auto Parts Pay the 25% Tariff?

The United States established an additional 25% tariff on certain imported automobiles and auto parts under Section 232 of its trade legislation. The levy began to apply to vehicles on April 3, 2025, and to certain auto parts by May 3 of the same year, at the latest. This measure does not grant the same treatment to all Mexican goods. The U.S. proclamation determined that the tariff would not apply to auto parts qualifying for T-MEC preferential treatment until the Department of Commerce established a process to exclusively tax their non-U.S. content. The exception is limited to individual parts that meet the treaty’s requirements. It does not include assembly kits or sets of parts, according to the document published in the Federal Register. The White House also reported that goods from Mexico and Canada that proved T-MEC rules of origin would retain the exemption from border-related tariffs. Products that did not meet the requirements could face an additional 25% rate. Thus, not all auto parts manufactured in San Luis Potosí are subject to the additional tariff. Its application depends on the tariff fraction, the origin of its inputs, and compliance with the trade agreement’s rules.

Mexico Produced 0.4% Fewer Vehicles, but Exported 1.4% More

Vehicle production offers another point of comparison. A broad decline in national manufacturing could reduce demand for parts and accessories; however, Mexico maintained practically the same level during the first half of 2026. According to the INEGI’s Administrative Registry of the Light Vehicle Automotive Industry, the results were as follows:

During the semester, Mexico produced 8,320 fewer vehicles but exported 23,061 more units. National production decreased by 0.4%, a considerably smaller variation than the 6.9% drop observed in Potosi exports of HS code 8708. At the same time, finished vehicle shipments grew.

U.S. Assembly Pace Increased 2.3%

U.S. production also did not experience a general contraction during the analyzed period. According to the U.S. Federal Reserve, the average seasonally adjusted assembly pace went from 10.35 million annualized vehicles during the first half of 2025 to 10.59 million in the same period of 2026. The difference represents a 2.3% growth. This indicator does not correspond to the number of vehicles manufactured during the semester; it expresses how many units would be assembled in a year if the observed monthly pace were maintained.

Source: U.S. Federal Reserve via FRED, series MVATOTASSS. Figures in millions of vehicles, at a seasonally adjusted annual rate.

The growth in the U.S. assembly pace and the stability of Mexican production do not support a general decline in North American vehicle manufacturing as a sufficient explanation for the reduction in Potosi exports.

Automobile Inventories Grew 19.3% Between January and May

U.S. inventories also registered movements during the period. Stocks of automobiles assembled in the United States, Mexico, and Canada increased from 180,269 units in January to 215,116 in May 2026. The increase was 19.3%, according to data from the U.S. Bureau of Economic Analysis disseminated by FRED. Furthermore, the value of inventories for vehicle and auto parts dealers reached $270.013 billion in June 2026. In the same month of 2025, it had reached $256.877 billion. The annual growth was 5.1%, according to Census Bureau data compiled by FRED. The records from Mexico and the United States do not support a generalized contraction in North American production broad enough to explain, on its own, the decrease in Potosi exports.

What Could Have Reduced San Luis Potosí’s Auto Parts Exports?

Public information rules out an automatic explanation but does not identify a single cause. The exported value can decrease due to various factors:

• Fewer parts shipped.
• Reduction in the average export price.
• Change in the component mix.
• Lower orders for specific lines or models.
• Supplier substitutions.
• Inventory adjustments.
• Difficulties in verifying regional origin.
• Tariff exposure for goods not meeting T-MEC.

Additionally, Data México reports monetary values but does not provide the physical volume of each component for this query. It cannot be determined whether San Luis Potosí exported fewer parts or if the average value of products sold changed. Moreover, the stability of national automotive production does not guarantee uniform orders for every supplier. An automaker can manufacture a similar volume of vehicles and, at the same time, modify models, components, inventories, or sources of supply.

You can read: https://www.liderempresarial.com/produccion-autopartes-san-luis-potosi-primer-semestre-2026/

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