Tax and Customs Legal Defense

The security, protection, and legal defense of our clients is one of the foundational pillars that drives our work every day.

When Mexico’s tax or customs authority acts, every day counts. More than 3,500 favorable outcomes support the technical and strategic capacity of our team to defend your company’s assets, the continuity of your operations, and your legal certainty before the SAT, ANAM, and any competent administrative authority.

Our team of professionals with more than 20 years of experience in the public and private sectors understands precisely how Mexico’s tax and customs authorities think, argue, and act. A perspective that can only be built from inside the system — and that we now put entirely at the service of your defense.

Public & Private
Sector Experience

+3,500

Favorable Outcomes

+20 years

Tax & Customs Experience

+750

Companies Defended

ISO 9001

Certified Processes

Our Defense Philosophy

Effective tax and customs defense does not begin in court — it begins with the first act of the authority. Every imprecise response to a request, every missed deadline, and every piece of evidence not submitted in time can significantly impact the taxpayer’s legal position.

At ST STRATEGO we operate under a clear premise: anticipate, structure, and execute. We anticipate the authority’s argument before it is formulated. We structure the defense on the basis of documentary, expert, and legal evidence. We execute with technical precision on every deadline, without exception.

This methodology, applied consistently and certified under ISO 9001, is the reason more than 3,500 matters have concluded with a favorable result for our clients.

Proceedings in Which We Act

We handle the full spectrum of tax and customs audit and litigation proceedings in Mexico, from the first act of the authority through to the final resolution. If your company has already received a notification, time is critical: contact us immediately.

DOMICILIARY AUDIT (Visita Domiciliaria)

The SAT designates auditors who appear at the company’s registered tax address with authority to review accounting records, documents, systems, and assets. It is the broadest and most operationally disruptive audit procedure available to Mexican tax authorities. Each partial audit report issued during the visit sets precedent for the final determination. The technical quality of responses, the strength of the evidence submitted, and the legal precision of arguments presented at the final report stage determine whether the authority issues a tax assessment, reduces it, or does not issue one at all. A reactive defense at this stage — waiting for the assessment to appeal — is always more costly than an active defense from day one of the audit.

Desk review (Revisión de Gabinete)

Review conducted at the SAT’s own offices through formal requests for information and documentation. While seemingly less intrusive, it carries identical technical risk: errors in the response generate observations that can escalate to substantial tax assessments.

Electronic Audit (Revisión Electrónica)

Initiated through the taxpayer’s tax mailbox (buzón tributario) based on automated cross-referencing of CFDI invoices, tax returns, and third-party data. Response deadlines are extremely short | 15 business days to rebut findings | and the probability of automatic assessments is high if the response is not technically precise.

Article 69-B procedure | nonexistent transactions (EFOS/EDOS)

Triggered when the SAT presumes that your company simulated transactions or received invoices from an EFOS (a company that issues invoices for nonexistent transactions). The impact is twofold: financial and reputational. Rebuttal deadlines are short and the evidentiary burden is demanding.

Administrative Customs Procedure (PAMA)

Initiated upon detection of irregularities during customs clearance: goods without documentation, incorrect tariff classification, challenged customs value. May result in precautionary seizure and a substantial tax assessment.

Circumstantial Reports (Actas Circunstanciadas)

Documents prepared by the authority during audits or inspections that record identified irregularities. Their content may be used as evidence in subsequent stages: rebutting their scope from the outset is critical.

Administrative Appeal (Recurso de Revocación)

First-instance challenge before the authority that issued the act. Strategically relevant for establishing precedent and preserving rights for subsequent stages.

Administrative Litigation / Nullity Suit (Juicio de Nulidad | TFJA)

Challenge before the Federal Administrative Justice Tribunal (TFJA). Allows annulment of SAT, IMSS, INFONAVIT, and other administrative authority resolutions based on substantive or procedural grounds.

Amparo Proceedings (Direct and Indirect)

Last line of constitutional defense. Indirect amparo protects against authority acts that affect fundamental rights during proceedings; direct amparo challenges final TFJA rulings before the Collegiate Circuit Tribunals.

Other Tax and Customs Authority Acts

Precautionary seizures, certification cancellations, program suspensions, VAT refund denials, penalties, and any administrative act affecting your company’s operations.

Audit Proceedings: What to Expect and How to Defend Your Company

Audit proceedings are the instrument through which Mexican authorities exercise their verification powers. Understanding their mechanics, deadlines, and consequences is the first step toward an effective defense.

01

Domiciliary Audit (Visita Domiciliaria)

The SAT designates auditors who appear at the company’s registered tax address to review accounting records, documents, and systems.

During the audit, partial reports and a final report are prepared. The taxpayer has 20 business days to submit evidence and arguments after the last partial report  | this is the most critical deadline in the entire proceeding. A technically sound response at this stage can prevent the issuance of a tax assessment or significantly reduce its amount.

  • ST STRATEGO accompanies your company from day one of the audit, coordinates interactions with the visiting auditors, reviews each report before it is signed, and structures the response to the final report with the technical rigor the proceeding demands.

02

Desk Review (Revisión de Gabinete)

A desk review is conducted at the SAT’s offices: the authority formally requests information and documentation, and the taxpayer must deliver it within the specified deadlines. Although it appears less confrontational than an on-site audit, the risk is equivalent: an incomplete or technically deficient response generates observations that can escalate to multi-million-peso tax assessments.

The review period is 12 months from the date the taxpayer responds to the first request. The authority may issue an observations notice to which the taxpayer has 20 business days to rebut.

  • We prepare each response with the supporting documentation needed to close observations at the desk review stage itself, preventing the file from advancing to more costly challenge stages.

03

Electronic Audit (Revisión Electrónica)

This is the most agile and technically demanding procedure operated by the SAT. Initiated through the taxpayer’s tax mailbox, it is based on automated cross-referencing of data. The authority presumes a discrepancy or irregularity and notifies the taxpayer with a preliminary assessment.

The taxpayer has only 15 business days to rebut the findings or accept the preliminary assessment. If there is no response | or if the response is insufficient | the SAT issues a final resolution on a near-automatic basis.

  • At ST STRATEGO we immediately analyze the questioned CFDIs, accounting records, customs entries, and tax returns | in both tax and foreign trade matters | to distinguish real inconsistencies from apparent ones, and we prepare the complete technical response within the deadline. Our success rate in electronic audits handled from the outset is significantly higher than in matters where the client engages us after deadlines have been compromised.

04

Article 69-B Procedure | Nonexistent Transactions (EFOS / EDOS)

This is one of the proceedings with the greatest financial and reputational impact in Mexico’s tax system. When the SAT presumes that a company issued invoices without real underlying transactions (EFOS), or received such invoices (EDOS), it publishes the company’s name in the Official Federal Gazette (DOF) and on the SAT’s own portal, and demands proof of the economic substance of the transactions.

The deadline to rebut EFOS status is 15 business days from publication in the DOF. For companies treated as EDOS, the deadline is 30 business days to correct their situation or prove that the transactions actually took place.

The consequences of inaction are severe: loss of tax effects of invoices received, potential joint and several liability, cancellation of digital tax seals, and possible criminal charges for tax fraud.

  • At ST STRATEGO we structure the legal and technical defense in Article 69-B proceedings, compiling and submitting to the authority a complete economic substance file with the necessary evidentiary elements. We have proven experience in high-complexity, high-value matters, with favorable outcomes for our clients.

05

Administrative Customs Procedure (PAMA)

A PAMA is initiated when the customs authority detects irregularities during goods clearance: insufficient documentation, challenged tariff classification, unproven customs value, goods of questionable origin, or undeclared excess quantities. The authority may precautionarily seize the goods and means of transport.

The importer has 10 business days to submit its rebuttal brief and offer evidence. Failure to do so | or insufficient evidence | may result in the authority issuing a final determination that includes omitted duties, penalties, and surcharges, plus the loss of the seized goods.

  • We handle the PAMA from the moment of seizure: we prepare the legal defense at the administrative stage. We also challenge the final determination before the TFJA when the authority does not yield through administrative channels.

Ordinary Stage: Challenge and Litigation

When the authority issues a determination of a tax assessment, penalty, or adverse administrative act, the challenge stage begins. At ST STRATEGO we litigate at all levels with the same technical rigor that characterizes our audit defense.

I

Administrative Appeal (Recurso de Revocación) before the SAT

This is the first-instance challenge before the authority that issued the act. A technically well-drafted appeal | with precise, properly supported grounds and backed by compelling evidence | is an effective and expeditious avenue for obtaining the revocation or modification of the challenged act.

The deadline to file is 30 business days counted from notification of the challenged resolution.

II

Administrative Litigation / Nullity Suit (Juicio Contencioso Administrativo) before the TFJA

The Federal Administrative Justice Tribunal (TFJA) is the specialized judicial body for challenging acts and resolutions issued by Mexico’s federal tax and customs authorities. It is the primary litigation route when the administrative appeal does not produce the expected result | or when the taxpayer opts to go directly to the tribunal without exhausting the administrative route first.

  • Our team has an established track record in litigation before the Regional Chambers and the Superior Chamber of the Federal Administrative Justice Tribunal, in matters primarily involving challenges to tax assessments. The technical depth of our litigation practice is the result of more than two decades of accumulated experience in both the public and private sectors.

III

Amparo Proceedings | Direct and Indirect (Juicio de Amparo)

The amparo is Mexico’s constitutional mechanism of last resort for the protection of fundamental rights against authority acts that violate them.

Indirect amparo applies against tax or customs authority acts that affect fundamental rights during the proceeding (seizures, cancellations, unlawful notifications, as well as against laws and decrees) and is processed before Federal District Courts. It allows for a request for provisional suspension of the challenged act from the moment the suit is filed | which can be decisive in stopping an imminent enforcement action.

Direct amparo applies against final TFJA rulings and is processed before the Collegiate Circuit Tribunals. It is the mechanism for correcting judgments that are contrary to Supreme Court (SCJN) jurisprudence or that incorrectly apply the law.

  • Our amparo practice in tax and customs matters integrates solid experience in constitutional analysis applied to tax and foreign trade disputes in Mexico. We have filed both direct and indirect amparo proceedings in high-complexity matters, obtaining federal court protection in cases involving the defense of fundamental rights against acts of tax and customs authorities. The request for provisional and definitive suspension forms part of our immediate defense strategy when the company’s operational continuity is at risk.

Critical Deadlines: Why Immediate Action Matters

In Mexican tax and customs law, deadlines are fatal: their expiration extinguishes rights. The table below summarizes the most critical moments in each proceeding and the action ST STRATEGO takes within each.

Proceeding

Critical Deadline

What ST STRATEGO Does Within That Deadline

Electronic Audit

15 business days

We analyze the information and documents challenged by the authority, then prepare and submit the full technical response with all supporting documentation before the deadline expires.

Domiciliary Audit | response to report

20 business days

We structure the submission of evidence and legal-accounting arguments to rebut each observation before it becomes a confirmed assessment item.

PAMA | initial rebuttal

10 business days from notification

We file the rebuttal brief with evidence and arguments to prevent the precautionary seizure from becoming a final tax assessment.

Article 69-B | rebutting the SAT's presumption

15 business days (DOF publication)

We structure the legal and technical defense, comprehensively analyzing the file to identify the strongest and most viable evidentiary elements to rebut the presumption of nonexistent transactions. Our proven experience in matters of this nature | including high-complexity, high-value cases | allows us to build a precise and well-grounded defense strategy at each stage of the proceeding.

Administrative Appeal

30 business days (resolution notified)

We formulate the appeal with the precise grounds that maximize the probability of revocation or nullity through this expeditious route.

TFJA Suit | complaint filing

30 business days (resolution notified)

We file the suit before the TFJA with the technically structured challenge arguments required to obtain a favorable judgment.

Indirect Amparo | urgent acts

15 business days (challenged act)

We file the amparo with a request for provisional and definitive suspension, to stay the effects of the challenged act while the merits are resolved.

What Distinguishes ST STRATEGO in Tax and Customs Legal Defense

Public sector experience

Several members of our team built their professional careers within Mexico’s tax and customs authorities. That deep understanding of normative criteria, institutional standards, and administrative procedure logic allows us to anticipate the development of each case and structure defense strategies with greater precision and technical grounding.

More than 3,500 favorable outcomes

This is not a count of files handled. It is the number of favorable resolutions our clients have obtained with our representation.

Integrated multidisciplinary team

Effective tax defense requires attorneys, accountants, and foreign trade specialists working on the same file. At ST STRATEGO that team is not outsourced: it operates under one roof, with ISO 9001 certified processes.

Immediate response in active contingencies

When we receive a case with running deadlines, we activate an urgent response protocol that ensures no deadline expires without an adequate technical response.

No ambiguity in results

We honestly assess the viability of each case before accepting it. We do not promise impossible results or prolong proceedings without justification.

Does your company have an active tax or customs contingency?

If you have received a notification from the SAT, ANAM, or any administrative authority — or if you anticipate an audit — contact us today. Every day without a structured defense strategy is a day the authority consolidates its position and your available options narrow.