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The liability changed in November 2025. On January 1, 2026 the reformed Ley Aduanera took effect, and your agencia aduanal became jointly and severally liable for the compliance of the operations it promotes, with the old exclusions removed. That is settled law. What was missing was the machinery to run it.
That machinery arrived. On February 23, 2026 the reform to the Reglamento de la Ley Aduanera was published in the DOF, in force the next day. The Law had required its own reglamento to be updated within 120 days, and the update did what a reglamento does: it turned principles into procedures, deadlines, assigned responsibilities, and mandatory technology. Solidary liability is no longer only a legal statement about who pays if something is wrong. It is now an operating model for how you and your agencia work together, day to day, before anything moves.
We have worked at this border for 122+ years, across 39+ ports, clearing more than 190,000 operations a year at a 99.8% accuracy rate. We have read every reglamento that touched this corridor. This one does something specific: it takes the liability shift most importers filed under "our broker's problem" and rebuilds the working relationship around it. This piece is not the explainer on the liability itself. That is the reform breakdown we published separately. This is what the new machinery means for how you run the relationship now.
From law to machinery: what the Reglamento operationalizes
A law can declare that your agencia is responsible. A reglamento decides how that responsibility gets enforced at the port, in the system, and on the file. The February reform does four things that reach your operation.
First, it makes the Sistema Electrónico Aduanero (SEA) the axis of the operation. Filings, validations, and records route through it, which means the quality of your data is no longer a back-office concern; it is the operation.
Second, it formalizes the Agencia Aduanal as a regulated subject in its own right, distinct from the individual agente persona física, with its own chapter of authorization, operation, and responsibility rules. The entity you contract with is now regulated as an entity.
Third, it hardwires electronic transmission across the chain: digital manifests, anticipated cargo data, electronic seals (candados electrónicos) on containers and cargo vehicles, and a formalized prevalidación regime. The protocol is no longer optional.
Fourth, it changes how the sector itself is populated. New agente convocatorias are now issued based on detected operational need rather than a fixed calendar, so the supply of new patentes tracks the authority's read of the market, not a schedule.
Read together, the pattern is unmistakable, and it is the same pattern we flagged in the reform breakdown: a move from facilitation to control. The Law set who is responsible. The Reglamento set how that responsibility is proven, transmitted, and audited.
Why your agencia aduanal is now a regulated entity
The single most useful reframe for a trade or foreign-trade director is this: the agencia is no longer a vendor that files paperwork on your behalf. It is a regulated entity that carries direct, non-excludable exposure to your compliance.
Under Articles 53 and 54 of the reformed Ley Aduanera, the agentes who operate as partners of an agencia are solidarily liable for the contributions and compliance of the operations they promote, and expressly responsible for the correct determination of contributions and for ensuring you hold documents that prove compliance, including non-tariff regulations and restrictions. The Reglamento then gives that liability its operational teeth. An entity that is exposed to your compliance will verify your compliance. That is not friction. That is the system working as designed.
treating the Reglamento as your agencia's homework. The verification your agencia now runs is the verification that keeps your cargo moving. An incomplete file is not a paperwork footnote. It is a held shipment, and under solidary liability it is a shared exposure that lands on both of you.
The electronic expediente is not "scanned PDFs"
Before the Reglamento, an importer could argue that a folder of digitized documents satisfied the file obligation. The February reform closes that argument. The electronic expediente now requires formally documented internal procedures, validation and verification mechanisms, and a backup system for the file itself. Digitizing documents is necessary and no longer sufficient.
On paper, this reads as one more obligation on the agencia. In practice, it redraws your side of the relationship. The expediente the Reglamento describes is built from your materiality evidence, your current corporate and tax documents, and your compliance declarations, assembled to a standard the authority can validate. If that evidence is scattered across your departments, the gap does not show up as an agencia problem. It shows up as your clearance time, your line schedule, and your CFO's questions.
The operational read: the file your agencia keeps on you is only as strong as the source documents you hand over, organized the way the Reglamento now demands.
Origin and value: two liability exclusions the Reglamento removed
Two changes in the February reform move documentation upstream, onto you, in ways worth naming precisely.
The first is origin. The Reglamento eliminates the exclusion that used to shield the agente from liability regarding the declared country of origin for goods identical or similar to those subject to a cuota compensatoria. Translated to your operation: your agencia can no longer treat origin as your representation to be taken on faith. It now shares the exposure, which means it will require verifiable origin evidence, bill-of-materials depth, and supplier documentation, before it declares.
The second is value. The Reglamento requires the documents under its Article 81 to be preserved as part of the manifestación de valor. This is the same value file that sits behind Mexico's now mandatory electronic MVE. Origin and value, the two determinations most likely to be challenged, now both demand upstream documentation that lives with you and flows to your agencia on time.
What to put in place with your agencia now
The Reglamento is in force. The work is not to react to an audit. It is to build the relationship the new machinery assumes you already have. Six moves, in the order that pays.
→ We run this as a single relationship-and-compliance review: contract instrument, expediente, materiality, origin, and value, mapped against the reformed Law and its Reglamento. If you want to close the gaps before they close a shipment, talk to a Joffroy expert.
What this looks like at Joffroy
We hold three Patentes Nacionales in Mexico, in Monterrey, Nogales, and Manzanillo, and a US Corporate Customs Brokerage License. The reform did not change how we work with our clients, because the relationship it now mandates, documented, verified, and technology-bound, is the relationship we have run for years. We monitor the DOF, SAT, and ANAM every business day, and we translated the February Reglamento into an operational checklist for our clients before most of the market had finished reading it.
The Law told you who is responsible. The Reglamento told you how that responsibility runs. The operations that treat their agencia as a compliance partner to equip, rather than a vendor to manage at arm's length, are the ones for whom none of this is a scramble.
TRADE. UNDER CONTROL.
