How to Vet a Mexican Supplier Before You Pay: a 12-Point Checklist

A good quote and a friendly sales call do not prove that a Mexican supplier is real, solvent and able to make your part. The time to check is before the first deposit leaves your account. This checklist is for US buyers who have a shortlist and want to confirm, with official Mexican and US lookups, that the company behind the quote is who it says it is.

TL;DR

• Ask for two SAT documents: the Constancia de Situación Fiscal (tax ID, legal name, registered address) and a positive Opinión de cumplimiento (32-D). Check the second one through its QR code.
• Search the supplier's RFC in the SAT 69-B list of taxpayers that invoice non-existent operations, and in the US Consolidated Screening List.
• Ask for the certificate number and confirm every ISO 9001, IATF 16949 or AS9100 certificate with the body that issued it or an official database.
• Approve a sample or first article, and pay in milestones only to a bank account in the supplier's legal name.

At a glance

Part 1: Is the company real? (checks 1–4)

1. Match the legal name and RFC. Every Mexican company has a tax ID called the RFC. Ask for the supplier's Constancia de Situación Fiscal, a SAT document that shows the RFC, legal name, tax regime and registered address. The legal name usually ends in a company type such as S.A. de C.V. or S. de R.L. de C.V. It must match the name on the quote, the contract and the bank account.

2. Ask for a positive 32-D compliance opinion. The Opinión del cumplimiento de obligaciones fiscales (article 32-D of the Federal Tax Code) shows whether the company is up to date with SAT. It is generated by the taxpayer, so ask the supplier for a recent copy. SAT explains how to check that it is genuine: scan the QR code on the PDF and make sure the folio, RFC, issue date and result shown by SAT match the document. If anything differs, do not accept it.

3. Search the SAT 69-B list. SAT publishes the RFCs of taxpayers presumed or confirmed to issue invoices for non-existent operations (often called EFOS). The list is public and searchable by RFC or name. A supplier on the definitive list is a hard stop.

4. Verify a real invoice (CFDI). All Mexican invoices are electronic CFDI documents. If the supplier has already invoiced you, for example for samples, check the CFDI on SAT's verification service with the folio fiscal, the issuer's RFC and the receiver's RFC. SAT shows whether it was certified and whether it is still valid or was cancelled.

Part 2: Can they make your part? (checks 5–8)

5. Confirm the plant address. The registered tax address and the plant are not always the same. Ask for the plant address in writing, then ask for a live video walk-through of the shop floor: the machines, the incoming material and the finished goods. Compare it with the address on the Constancia. For larger orders, visit in person or send an auditor.

6. Check every certificate at the source. A PDF certificate is easy to copy. Ask for the certificate number, the issuing certification body, the site address and the scope. Then check:

• ISO 9001: many certificates from accredited bodies can be searched on IAF CertSearch. If you cannot find it, ask the certification body named on the certificate to confirm it.
• IATF 16949 (automotive): confirm it with the issuing certification body. Make sure the certified site is the plant that will make your part.
• AS9100 (aerospace): search the IAQG OASIS database.

Check that the scope covers your process (a certificate for "machining" does not cover welding) and that it has not expired. See ISO 9001 and IATF 16949 in our glossary.

7. Ask for capability evidence, not claims. Request a machine list with bed sizes or tonnage, photos of similar parts, and examples of inspection reports. Ask which steps they do in-house and which they outsource, such as heat treatment, plating or powder coating.

8. Call two references. Ask for customers, ideally in the US, who buy similar parts. Ask them about on-time delivery, how quality problems were handled, and whether they would order again.

Part 3: Can they ship it to you correctly? (checks 9–11)

9. Approve a sample or first article. Before production, agree on a sample or a first article inspection report against your drawing. For automotive parts, ask whether they can deliver a PPAP package.

10. Check export readiness. Ask who files the Mexican export declaration (the pedimento) and through which customs broker. Ask whether the supplier can provide the information you need for a USMCA certification of origin. A supplier that has never exported will need more help.

11. Screen against US restricted-party lists. Search the company and its owners on the US Consolidated Screening List run by the International Trade Administration. It combines export and sanctions lists from several US agencies in one search.

Part 4: Pay safely (check 12)

12. Pay in milestones, to the legal entity only. Tie payments to events you can check: sample approval, inspection before shipment, delivery. Pay only to a bank account in the supplier's legal name as shown on the Constancia. Treat any late request to change bank details as a warning sign, and confirm it by phone with a contact you already know. Put the milestones, the inspection criteria and the Incoterms rule in the purchase order.

When to audit on site

A remote check is often enough for a small first order of simple parts. Plan an on-site audit when the part is safety-critical, the order is large, the supplier will hold your tooling, or the remote checks raised questions. An audit should cover the process for your part, calibration of measuring equipment, how nonconforming parts are kept apart, and material traceability.

Suppliers on Suconex

Six examples of suppliers whose profiles state a quality certificate. The descriptions and certificates come from each company's Suconex profile; check them yourself as shown in step 6.

• Metalistik (Aguascalientes): high-volume precision metal components, including stamping, tooling, machining, assembly and powder coating. The profile states Tier-Q 5.0 and ISO 9001:2015.
• PSM – Progressive Stamping de México (Querétaro): stamped parts and subassemblies for the automotive, electrical and electronics industries. The profile states IATF 16949.
• Precisión Omega (Chihuahua): precision machined parts with CNC milling and turning plus finishing. The profile states ISO 9001:2015.
• Fimac Coahuila (Saltillo, Coahuila): metal fabrication and assembly, and fiberglass manufacturing. The profile states ISO 9001:2015.
• LRP Metal Solutions (Aguascalientes): precision machining, industrial welding and process automation. The profile states ISO 9001.
• Litocalidad (Puebla): printed packaging, labels, folding boxes and flexible packaging. The profile states ISO 9001:2015.

Listing on Suconex is not an endorsement. Browse more on the supplier directory.

Trade compliance to check before you pay (as of October 29, 2026)

Last checked: October 29, 2026. Sources: the official US government documents listed under Sources (CBP, USTR, USITC).

Vetting the supplier also means checking that the goods can enter the US at the cost you expect.

• USMCA proof of origin. To claim USMCA preference you need a certification of origin. CBP accepts any format that contains the nine minimum data elements. Ask early whether the supplier can give you the data.
• 10% Section 301 duty on goods of Mexico. Since July 24, 2026, products of Mexico pay an extra 10% (HTS 9903.05.55). It does not apply to products of Mexico entered duty-free under USMCA. Goods already subject to the Section 232 duties on metals or wood products are also excluded.
• Section 232 metals. Steel, aluminum and copper articles and many derivative products pay Section 232 duties of up to 50% even when they qualify for USMCA. Ask your broker to check the HTS line before you sign.

Rates change often. Confirm with your customs broker before each new product ships.

How Suconex helps

Suconex finds suppliers that fit your part, contacts them in Spanish, and checks them before you see a quote. Send one part through the price check and you get the quotes in one table: unit price, tooling, lead time and certifications.

Get quotes from Mexican suppliers →

FAQ

How do I check if a Mexican company is legitimate?

Ask for its Constancia de Situación Fiscal and a positive 32-D compliance opinion, and check the opinion's QR code with SAT. Search the RFC in the SAT 69-B list and the company on the US Consolidated Screening List. Then confirm the plant with a video walk-through or a visit.

What is an RFC and why does it matter?

The RFC is the Mexican tax ID. It ties the quote, the invoice (CFDI) and the bank account to one legal company. If the names or RFCs on these documents do not match, stop and ask why.

How do I verify an ISO 9001 or IATF 16949 certificate?

Ask for the certificate number, the certification body and the certified site. Search ISO 9001 on IAF CertSearch or ask the certification body; confirm IATF 16949 with the issuing body; search AS9100 on IAQG OASIS. Check the scope and the expiry date.

Should I pay a deposit to a Mexican supplier?

Deposits are common, especially for tooling and material. Keep them tied to milestones such as sample approval and inspection before shipment, and pay only to an account in the supplier's legal name.

When do I need an on-site audit?

For safety-critical parts, large orders, supplier-held tooling, or when remote checks raise doubts. For a small first order of simple parts, remote checks and an approved sample are often enough.

Does Suconex verify suppliers?

Yes. Suconex contacts and checks suppliers before it sends you their quotes. You should still approve a sample and agree on payment terms that protect you.