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"Know your customer" used to be a banking phrase. In 2026, it became a customs requirement.
If your Mexican customs broker has been asking for more paperwork than ever — your constitutive documents, proof of your tax standing, photographs of your facility, a signed statement that you're not linked to a blacklisted taxpayer — you are not being singled out. You are watching a legal obligation take effect.
Since January 1, 2026, every customs broker (agente aduanal) in Mexico is required to build and safeguard an electronic file on each company that asks them to clear cargo. The requirement comes from Regla 1.4.14 of the Reglas Generales de Comercio Exterior 2026, which operationalizes Article 162, fracción VI of the Ley Aduanera. This is what the industry now calls the broker's KYC file — and understanding what goes in it is the difference between cargo that clears on schedule and cargo that waits.
This guide breaks down what the file is, the document groups that make it up, and what happens when it's incomplete. It's the anchor reference for our other pieces on the 2026 reform — read this one first.
What the KYC file actually is
The KYC file — formally, the expediente electrónico del usuario — is a structured record the broker maintains for every importer or exporter they represent. Under Regla 1.4.14, the broker must integrate and store the documentation that proves who you are, that you have the operational capacity to do what you say you do, and that you are clear of Mexico's principal tax-fraud watchlists. The rule states it plainly: the broker must integrate and safeguard an electronic file containing each user's information, and the authority can demand it during the exercise of its review powers.
It is worth being precise about what changed, because the file itself is not entirely new. Brokers have always collected some client documents. What 2026 did was raise the standard from legal existence to operational reality. The authority is no longer satisfied with an acta constitutiva and an RFC — under Regla 1.4.14 it now expects proof of real operating capacity.
📋 Quick check: If your broker last refreshed your file more than three years ago — or if your business address, legal representatives, or activity changed and you never told them — your expediente is likely out of date under the new rule.
There's a second half to this you should know about: the doble expediente. Regla 1.4.14 governs the file the broker keeps on you. A parallel rule, Regla 3.1.42, governs a materiality file you keep on your own operations. Together, Regla 1.4.14 and Regla 3.1.42 form a two-sided model of documentary control. This guide covers the broker's file. The materiality file is its own subject.
Why it matters: the liability behind the paperwork
The paperwork exists because the consequences moved. The reform to the Ley Aduanera published in the DOF on November 19, 2025, effective January 1, 2026, made the customs broker a responsable solidario — jointly and severally liable — for the contributions and compliance tied to the operations they promote. Under the reformed Article 53 of the Ley Aduanera, brokers who operate as partners of an agencia aduanal are now jointly and severally liable, not merely subsidiarily liable, and the previous grounds that excused them from responsibility were eliminated.
Translated into operational terms: your broker can no longer point to your bad data as a defense. If something in your declaration is wrong, they are on the hook alongside you. The file is how they verify — and document that they verified — before they put their patente on the line for your cargo.
That liability is not abstract. ANAM reported that in 2025 it had opened 45 administrative proceedings against customs brokers, resulting in 34 patente cancellations and one suspension (ANAM, Comunicado de prensa 22/2025, October 13, 2025). A broker who clears your cargo on an incomplete file is risking the license that lets them clear anyone's cargo. That is why the requests have an edge they didn't have before.
How it works: the document groups
The file is organized into recognizable groups. The exact list lives in the text of Regla 1.4.14, which sets out the following categories.
Corporate and identity. For companies, the acta constitutiva or notarial instrument; for individuals, official identification. The documents that establish who the legal entity is.
Powers and representation. The poderes that prove the people signing and instructing on your behalf are authorized to do so.
Tax standing. Documentation of your fiscal situation — your standing with the SAT, your RFC, and the constancia that supports it.
Address and materiality. Proof of domicile, and — this is the demanding part — evidence that you actually operate where you say you do. Regla 1.4.14, in its fracción V, calls for georeferenced photographs documenting the facade, the warehouse, the machinery, the office equipment, and the personnel. The rule is reaching for operational reality, not a paper shell.
Assets and commercial capacity. Documentation supporting the legal property or possession of the goods and the resources used to carry out the foreign-trade operation — a point the reform to Article 162 reinforces.
Compliance declarations. Statements under oath (bajo protesta de decir verdad), including a declaration that you are not linked, in the terms of Article 68 of the Ley Aduanera, to taxpayers on the watchlists referenced in Articles 49 Bis, 69, 69-B, and 69-B Bis of the Código Fiscal de la Federación.
Common mistake: Treating the materiality photographs as a formality. A blurry, undated, un-georeferenced image set is one of the fastest ways to leave a file technically incomplete — and an incomplete file is the broker's problem, which quickly becomes your delay.
Two operating details matter as much as the contents. First, the file must be updated every three years, or sooner whenever you inform your broker that previously supplied information has changed, per the text of Regla 1.4.14. Second, the broker must verify you against the SAT watchlists — not once, but on an ongoing basis, because a supplier or counterparty can land on a list after your file was built.
Common misconceptions
"This is just my broker being cautious." It's a legal obligation with sanctions attached. Under Regla 1.4.14 and Article 162, fracción VI of the Ley Aduanera, omission or deficiency in the file is a breach of the broker's obligations and can be required by the authority during the exercise of its review powers.
"Once the file is built, we're done." The three-year refresh and the change-triggered updates make this a living record, not a one-time submission.
"The watchlist check is the broker's problem, not mine." The check protects you too. If a counterparty appears on the SAT's Article 69-B list, your clearance can stall regardless of your own good standing — which is exactly why we cover the 69-B list in its own piece in this cluster.
"A carta encomienda covers the relationship." It enables the clearance, but under the new architecture it is no longer a legal shield on its own. The contractual and documentary relationship has to carry more weight than a single letter.
When to bring in expert help
If your operation spans multiple entities, multiple ports, or high-SKU volume, assembling a clean, consistent file across all of them is not a clerical task — it's a compliance project. The same is true if you've grown fast: rapid expansion is precisely where files fall out of date and materiality evidence lags behind the operation.
At Joffroy, we run this file the way 122 years at the US–Mexico border taught us to run everything — as a daily discipline, not an annual scramble. Across 190,000+ annual customs operations and our three Patentes Nacionales, the expediente is the foundation the clearance sits on, not an afterthought bolted on when an audit looms. We review client files against Regla 1.4.14 as a standard part of onboarding, and we refresh them before they expire — not after a held shipment forces the issue.
The KYC file is not bureaucracy your broker invented. It's the operational backbone of a clearance system that now holds both of you accountable. Treat it that way, and the paperwork stops being friction and starts being protection.
If you're not sure your expediente would survive an audit, ask us to review it against Regla 1.4.14 before the authority does. Talk to a Joffroy expert.
TRADE. UNDER CONTROL.
