Wire, cable and wiring harnesses: copper in the Mexico-US auto chain

Written By Shrinivas G
← Mexico Trade Corridor

Mexico Trade Corridor · Product brief · HS 8544

Wire and cable is Mexico's fifth-largest export to the United States, and most of it is wiring harnesses for vehicles. This brief sets out the numbers from both sides, the copper and auto tariffs in force, and why copper prices drive harness makers' need for working capital.

Published October 23, 2026 · Facts as of October 23, 2026 · 10 min read · Trade data: UN Comtrade, 2020 to 2025 · Rules as of October 23, 2026

Facts as of October 23, 2026. This page states the facts as they stood on that date. Tariffs, rules and figures may have changed since publication. Tariffs and trade policy change often, so we review these pages every month and update them.

#5

Mexico's No. 5 export to the US in 2025, ranked by value as reported by Mexico (UN Comtrade, 4-digit HS codes). It is also No. 10 among imports from the US. The US figure is shown beside it because the two countries count the same trade differently.

US$18.7bnMexico's exports to the US, 2025, as reported by Mexico
US$17.9bnThe same flow, 2025, as reported by the US
+80.4%Change 2020 to 2025, Mexico data
US$3.5bnMexico's imports from the US in the same code, 2025, Mexico data

What is it?

HS 8544 covers insulated electric wire and cable, with or without connectors, and optical fiber cable. Its largest line is the vehicle wiring harness. Mexico reported US$18.7 billion of these exports to the US in 2025 1.

Why does it matter?

Wire and cable is Mexico's No. 5 export to the US and its No. 10 import from the US 1. Copper is the main raw material, and its average price in 2026 to mid-October was 40.40% above the same period of 2025 2,3.

How does it work?

Harness makers cut and assemble wire, terminals and connectors to each vehicle maker's drawing, mostly by hand. They buy copper wire before they invoice, and ship harnesses by truck to vehicle plants in all three USMCA countries 2,9.

01How big is the wire and cable trade between Mexico and the US?

Mexico reported US$18.7 billion of wire and cable exports to the US in 2025. That is up 80.4% from US$10.4 billion in 2020, and up 9.0% from 2024 1. Wire and cable was 3.4% of Mexico's US$545.4 billion of reported exports to the US 1.

Trade also runs south. Mexico reported US$3.5 billion of wire and cable imports from the US in 2025, up 45.8% since 2020 and up 4.9% from 2024 1. On Mexico's figures, the country sold US$15.2 billion more wire and cable to the US than it bought 1.

The two sides differ most on the southbound flow. US data shows US$17.9 billion of imports from Mexico and US$5.0 billion of exports to Mexico in 2025. That is US$1.4 billion more southbound trade than Mexico recorded 1. Our data gap explainer sets out why the two sides differ.

Chart

Wire and cable trade, both directions, both sides of the data

Trade in HS 8544, 2020 to 2025, US$ billionMexico to US, Mexico data: 10.4 in 2020 to 18.7 in 2025; Mexico to US, US data: 9.9 in 2020 to 17.9 in 2025; US to Mexico, Mexico data: 2.4 in 2020 to 3.5 in 2025; US to Mexico, US data: 2.8 in 2020 to 5.0 in 2025.0510152020202021202220232024202518.717.95.03.5
  • Mexico to US, Mexico data
  • Mexico to US, US data
  • US to Mexico, Mexico data
  • US to Mexico, US data
US$ billion. Solid lines: as reported by Mexico. Dashed lines: as reported by the US. Source: UN Comtrade, 2020 to 2025.

02Which wire and cable products cross the border?

Wiring harnesses lead. HS 854430 covers wiring sets used in vehicles, aircraft and ships. It was US$11.0 billion in 2025, or 58.6% of the total, as reported by Mexico. US data shows US$11.2 billion 1. Harnesses are classed under HS 8544, so they sit outside the auto parts figures for HS 8708.

Low-voltage cable fitted with connectors follows at US$2.9 billion, or 15.2%. Optical fiber cable was US$2.0 billion and low-voltage cable without connectors US$1.8 billion 1.

The southbound mix is different. Low-voltage cable without connectors is the largest line Mexico buys from the US, at US$1.3 billion in 2025, or 35.8% of its imports in this code. Harnesses follow at US$0.8 billion, or 22.7% 1. Inputs used to make goods for export can enter Mexico under the IMMEX program.

Chart

The largest wire and cable lines Mexico ships to the US

Vehicle wiring harnessesHS 85443011.0 (58.6%)Low-voltage, connectorsHS 8544422.9 (15.2%)Optical fiber cableHS 8544702.0 (10.7%)Low-voltage, no connectorsHS 8544491.8 (9.6%)Cable over 1,000 VHS 8544600.4 (2.3%)Copper winding wireHS 8544110.4 (2.2%)
US$ billion and share of the 4-digit total, 2025, as reported by Mexico. Source: UN Comtrade.

03Who makes the harnesses, and where?

Large global groups lead the industry. Aptiv had about 140,000 employees at the end of 2025, 50% of them in North America, "with our largest presence in Mexico" 2. Other harness suppliers with Mexican plants include Draexlmaier, Lear, Leoni, Sumitomo and Yazaki 5.

Investment continues. Yazaki runs four plants in San Nicolás de los Garza, Nuevo León, that make wiring harnesses and electronic components, and an engineering center in Santa Catarina with more than 1,000 staff. In April 2026 it announced a new US$66 million investment, and it names GM, Stellantis and Ford as customers 6. Leoni is investing MXN 196.2 million in Durango, with 500 direct jobs and 14 new lines for harnesses for electric and autonomous vehicles 7.

Harnesses also serve aircraft. Safran opened a 10,600 square meter wiring harness plant in Chihuahua on July 1, 2026, for Airbus, Boeing and Dassault. Its Chihuahua workforce is 4,280 8.

04How do harnesses get from the plant to the buyer?

Harnesses travel by truck to vehicle plants in Mexico, the US and Canada. In 2025, Laredo, Texas handled 46.1% of the value of US-Mexico truck trade. Ysleta in El Paso handled 17.5% and Otay Mesa 9.1% 9. Our guide to border crossings covers each port.

Each harness is built for one vehicle program, so deliveries follow the vehicle plant's schedule. The sale contract sets who pays for each leg and who clears customs, usually through an Incoterms rule. The Incoterms guide explains each one.

  1. Copper wireWire makers draw copper rod and insulate it. Some wire comes from the US.
  2. Harness plantWorkers cut, crimp and assemble wire, terminals and connectors into a harness, in Nuevo León, Chihuahua, Durango or another state.
  3. PaperworkThe maker issues a commercial invoice and a USMCA certification of origin. A customs broker files the Mexican export declaration.
  4. Truck to the borderHarnesses travel north by truck. Laredo handles the largest share of truck trade value.
  5. Vehicle plantThe harness reaches an assembly plant in the US, Mexico or Canada. The invoice is now due on the agreed terms.

05Which rules and tariffs apply?

Copper raises most of the tariff questions. Since August 1, 2025, the US has charged a Section 232 duty of 50% on the copper content of listed semi-finished copper products and copper-intensive derivatives, under Proclamation 10962. Refined copper, ores and cathodes are outside its scope, and auto parts for passenger vehicles and light trucks are excluded 4. The US customs list for that proclamation named four 8544 subheadings: 8544.42.10, 8544.42.20, 8544.42.90 and 8544.49.10 10.

Proclamation 11032 reset the metals rates from June 8, 2026, on full value: 50% for Annex I-A articles, 25% for Annex I-B derivatives and 15% for Annex I-C and Annex III goods 11. Which annex now holds each 8544 line is still to be confirmed, so each tariff line must be checked. The US Commerce Department has also proposed adding four more cable lines at 25%. Comments closed on August 27, 2026, and we found no final decision as of October 23, 2026 12,13,14.

Vehicle harnesses are auto parts. A harness whose tariff line is on the Section 232 auto parts list pays 25%, unless it qualifies under USMCA. Qualifying parts are exempt until Commerce sets a process to tax their non-US content 15,16. Our guide to USMCA rules of origin explains the certificate. The 10% Section 301 tariff on Mexican goods does not apply to goods entered with a USMCA claim 17. All rates here are as of October 23, 2026.

Rules in force
As of October 23, 2026. Live list: corridor watch.
MeasureWhat it doesSinceStatus
US Section 232, copper (Proclamation 10962)50% on copper content of listed products. CBP list named 8544.42.10, .20, .90 and 8544.49.10. Auto parts excluded 4,10Aug 1, 2025In force
US Section 232, metals (Proclamation 11032)50% (Annex I-A), 25% (Annex I-B) or 15% (Annex I-C and III) on full value. Annex for each 8544 line to be confirmed 11Jun 8, 2026Check annex
Proposed cable additions25% on 8544.49.2000, 8544.49.3040, 8544.49.3080 and 8544.60.4000. Comments closed Aug 27, 2026 12,14Aug 6, 2026Proposed
US Section 232, auto parts25% on listed parts. USMCA-qualifying parts exempt until Commerce sets a process to tax non-US content 16May 3, 2025In force
USMCA auto rules of origin75% regional value content for vehicles and core parts 15Jul 1, 2020In force
US Section 301, forced labor10% on Mexican goods. Exempt with a USMCA claim; goods under Section 232 excluded 17Jul 24, 2026In force

06Where do harness makers need cash, and how is it financed?

Copper is paid for before the harness is invoiced. LME copper closed at 669.094 US cents per pound, about US$14,751 per tonne, on October 14, 2026 3. When copper costs more, the same volume of harnesses ties up more cash. Aptiv says contract clauses have let it pass some copper price increases to customers 2.

Payment terms are long. Atradius reports that half of Mexican firms give one month at most, that two- to three-month terms are common, and that medium and large industrial firms give the longest terms. About one fifth of B2B invoices in Mexico are overdue 19.

Most harnesses are sold on open account terms, so the maker's unpaid invoices are its largest short-term asset. Our guides to finance for tier 1 and tier 2 suppliers and factoring in Mexico go further.

Where the cash goes

From copper purchase to payment

  1. Program award
    Tooling and set-upThe harness maker sets up assembly boards and lines for a new vehicle program.
  2. Before production
    Copper and componentsWire, terminals and connectors are bought, some from the US. Copper prices set much of the cost.
  3. Production
    WagesAssembly is mostly by hand, so wages are a large share of the cost.
  4. Invoice
    Waiting for paymentThe vehicle maker pays on its terms. Two- to three-month terms are common in Mexico 19.
  5. Payment
    Cash returnsDeductions or disputes can cut or delay the payment. See deductions and chargebacks.
The order of cash needs is typical for a harness maker. Actual days depend on each contract.
Before shipmentPre-shipment finance

Funds copper, components and wages against a confirmed vehicle program.

Copper stockInventory finance

Funds wire and copper held in stock, with the stock as security.

After invoice, large buyerPayables finance

The vehicle maker approves the invoice and a finance provider pays the harness maker early.

After invoice, any buyerFactoring or invoice discounting

The harness maker sells or borrows against its unpaid invoices.

LME copper closed at about US$14,751 per tonne on October 14, 2026. Harness makers buy copper before they invoice.

07What should wire and cable traders watch next?

Three decisions matter most: the final ruling on the proposed cable lines, the annex placement of 8544 lines under Proclamation 11032, and any duty on refined copper 4,11,12. USMCA stays in force. On July 1, 2026 the US did not agree to renew it in its current form, so annual joint reviews follow until 2036 unless the three countries confirm an extension 18. The live list of measures is on our corridor watch page.

  • PendingFinal Commerce decision on adding four 8544 cable lines to Section 232 at 25%. Comments closed August 27, 2026 12,14.
  • By Dec 2026Next round of US-Mexico talks on autos. No date announced as of October 18, 2026 20.
  • Jan 1, 2027Start date for a 15% duty on refined copper recommended in 2025. The Commerce update due June 30, 2026 has not been found 4.
  • 2027Leoni plans the second 250 of its 500 new jobs in Durango 7.
  • Dec 31, 2027Section 232 metals rates under Proclamation 11032 run to this date 11.
  • Jul 1, 2036USMCA ends on this date unless the three countries confirm an extension. Annual reviews run until then 18.

Questions traders ask

How much wire and cable trade is there between Mexico and the US?

Mexico reported US$18.7 billion of wire and cable exports to the US in 2025 and US$3.5 billion of imports from the US, under HS 8544. US data shows US$17.9 billion of imports from Mexico and US$5.0 billion of exports to Mexico.

What is a wiring harness, and how big is the trade?

A wiring harness is a set of wires, terminals and connectors that carries power and signals through a vehicle, aircraft or ship. Mexico reported US$11.0 billion of harness exports to the US in 2025, or 58.6% of its wire and cable exports to the US.

Do Mexican wire and cable exports pay the US copper tariff?

It depends on the tariff line. Four 8544 subheadings were on the US customs list for the 2025 copper tariff, and auto parts for passenger vehicles and light trucks were excluded. Under Proclamation 11032 the rate depends on the annex that lists the line, so each line must be checked. These rules are as of October 23, 2026.

Who makes wiring harnesses in Mexico?

Aptiv, Yazaki, Leoni, Lear, Sumitomo and Draexlmaier all make harnesses in Mexico. Safran makes aircraft harnesses in Chihuahua.

Why do copper prices matter to harness makers' cash?

Harness makers buy copper wire before they invoice the vehicle maker, and wait two to three months or more to be paid. When copper costs more, the same volume ties up more working capital. Some contracts let makers pass copper price increases to customers.

Trading wire, cable or wiring harnesses between Mexico and the US? Ossiano Capital works on trade finance in this corridor.

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Sources and notes

  1. UN Comtrade, annual trade data 2020 to 2025, HS 8544, Mexico and the US as reporters. Downloaded October 2026; 2025 figures may be revised. https://comtradeplus.un.org/
  2. Aptiv PLC, Form 10-K for fiscal year 2025, US Securities and Exchange Commission. https://www.sec.gov/Archives/edgar/data/1521332/000152133226000009/aptv-20251231.htm
  3. Reporte Minero, copper price (Cochilco data), October 14, 2026. https://www.reporteminero.cl/noticia/noticias/2026/10/precio-cobre-alza-anual-40-porciento-cotizacion-bolsa-londres-inventarios
  4. The White House, Adjusting imports of copper into the United States (Proclamation 10962), July 30, 2025. https://www.whitehouse.gov/presidential-actions/2025/07/adjusting-imports-of-copper-into-the-united-states/
  5. ASSEMBLY Magazine, Proposed tariffs could impact wire harness supply chain, January 31, 2025. https://www.assemblymag.com/articles/99046-proposed-tariffs-could-impact-wire-harness-supply-chain
  6. Cluster Industrial, Yazaki fortalece su presencia en Nuevo León con inversión acumulada de 36.5 mdd, April 7, 2026. https://clusterindustrial.com.mx/yazaki-fortalece-su-presencia-en-nuevo-leon-con-inversion-acumulada-de-36-5-mdd/
  7. Cluster Industrial, Leoni invierte 196.2 mdp en Durango para la producción de arneses para vehículos eléctricos, February 25, 2026. https://clusterindustrial.com.mx/leoni-invierte-196-2-mdp-en-durango-para-la-produccion-de-arneses-para-vehiculos-electricos/
  8. Safran, Safran strengthens its footprint in Mexico with two new plants in Querétaro and Chihuahua, July 2, 2026. https://www.safran-group.com/news/safran-strengthens-its-footprint-mexico-two-new-plants-queretaro-and-chihuahua-2026-07-02
  9. Air Freight News, US Bureau of Transportation Statistics transborder freight data, 2025 annual report, March 17, 2026. https://airfreight.news/articles/full/transborder-freight-data-annual-report-2025
  10. Thompson Coburn, Proclamation imposing 50% Section 232 tariffs on copper (CBP list), August 2025. https://www.thompsoncoburn.com/insights/trump-administration-issues-proclamation-imposing-50-section-232-tariffs-export-controls-on-some-copper-scrap/
  11. The White House, Further adjusting the tariff regimes for imports of aluminum, steel and copper (Proclamation 11032), June 1, 2026. https://www.whitehouse.gov/presidential-actions/2026/06/further-adjusting-the-tariff-regimes-for-imports-of-aluminum-steel-and-copper/
  12. SteelOrbis, US proposes expanding Section 232 tariffs to 14 additional derivative product categories, August 11, 2026. https://www.steelorbis.com/steel-news/latest-news/us-proposes-expanding-section-232-tariffs-to-14-additional-derivative-product-categories-1470151.htm
  13. KPMG TaxNewsFlash, US BIS Section 232 tariffs: derivative articles, August 2026. https://kpmg.com/us/en/taxnewsflash/news/2026/08/us-bis-section-232-tariffs-derivative-articles.html
  14. V. Alexander & Co, Department of Commerce proposes new Section 232 duties on 14 derivative products, August 5, 2026. https://www.valexander.com/2026/08/05/dept-of-commerce-proposes-new-sec-232-duties-on-14-derivative-products/
  15. Dickinson Wright, Summary of automotive provisions of USMCA. https://media.dwlaw.com/wp-content/uploads/2026/07/03153713/summary-of-automotive-provisions-of-usmca-1.pdf
  16. Steptoe, New tariffs on imports of automobiles and automobile parts, April 16, 2025. https://www.steptoe.com/en/news-publications/global-trade-and-investment-law-blog/president-trumps-new-tariffs-on-imports-of-automobiles-and-automobile-parts-key-updates-and-implications.html
  17. EY Tax News, USTR finalizes Section 301 forced labor tariffs on 60 economies, July 2026. https://taxnews.ey.com/news/2026-1607-ustr-finalizes-section-301-forced-labor-tariffs-on-60-economies-additional-tariffs-of-10-percent-or-125-percent-take-effect-24-july-2026
  18. White & Case, USMCA 2026 joint review: United States declines to extend agreement, July 2, 2026. https://www.whitecase.com/insight-alert/usmca-2026-joint-review-united-states-declines-extend-agreement-triggering-annual
  19. Atradius, B2B payment practices trends in Mexico, 2026. https://atradius.us/knowledge-and-research/reports/b2b-payment-practices-trends-in-mexico-2026
  20. ICPA, USMCA joint review automotive tracker, October 18, 2026. https://www.icpainc.org/usmca-joint-review-automotive/

Trade values are US dollars from UN Comtrade at the 4-digit HS level unless a 6-digit line is named. Mexico and the US record the same shipments under different rules for value, country of origin and timing, so their figures differ. Percent changes compare 2025 with 2020. All facts on this page are as of October 23, 2026, the date of publication, and may have changed since. Rules and tariffs are as of October 23, 2026 and change often: check the corridor watch before you act.

About this brief. Prepared for Ossiano Capital. People planned, researched, wrote and checked this brief, using AI tools to help with research and checking. You are welcome to quote or reuse it: please credit Ossiano Capital and link to this page.

Shrinivas G https://www.mashedavocado.com
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