How to Audit Your Anexo 24 Before SAT Does

Losing your IMMEX program does not start with an audit. It starts with an inventory control system that quietly stopped reconciling months earlier, while everyone assumed the software was handling it. By the time the authority runs the numbers, the gap is already there. This guide shows you how to run that same reconciliation yourself, on your own Anexo 24, before anyone from SAT ever asks.

Anexo 24 is the automated inventory control system that every operation under the IMMEX program must keep for the merchandise it brings in temporarily. If you want the ground-up explainer of what it is and why it decides whether your program survives, we wrote that separately. This piece is the operational version: the self-audit, step by step, run the way the authority reads it. It is written for the Trade Director and the Operations Manager who own the consequences, not the vendor who sold the software.

The obligation did not change on January 1. The enforcement did.

The requirement itself is old. Article 59, fracción I of the Ley Aduanera obliges anyone who imports merchandise to keep inventory control in an automated and permanent form, with the control data kept current at all times and available to the authority. For IMMEX operations, Anexo 24 of the RGCE is the specification of that system: the catalogs, the customs modules, and the reports it has to contain. None of that is new.

What changed is everything around it. The reform to the Ley Aduanera published in the DOF on November 19, 2025, in force January 1, 2026, formalized the Agencia Nacional de Aduanas de México (ANAM) as the inspection and enforcement authority and reinforced the language of Article 59. One point deserves precision, because a lot of the coverage blurred it: the new real-time monitoring, video surveillance, and interoperable-access requirements in the reform fall on recintos fiscales and recintos fiscalizados, the bonded facilities, under Articles 14, 14-A, and 14-D. They are not a new obligation on every IMMEX plant.

On paper, then, your Anexo 24 obligation reads almost exactly as it did in December. In practice, the reconciliation you could once let slip for a quarter and fix later is now the first thing a formalized enforcement body pulls, in an environment where a temporary import that cannot prove where it went is treated as a definitive one, with the deferred contributions due and surcharges on top. The obligation is the same. The cost of a descuadre (a mismatch) is not. That is the reason to audit now, on your schedule, instead of later, on theirs.

Before you start: the five inputs to pull

A real reconciliation is a cross-check, and you cannot cross-check what you have not pulled. Assemble five things before you open a single report.

1️⃣ Your pedimento universe for the period: every temporary import pedimento and every discharge pedimento (returns, exports, transfers, changes of regime) for the window you are auditing, usually the last sixty to ninety days.

2️⃣ Your Anexo 24 reports: the entries report, the exits report, the balances (saldos) report, and the materials-used report the system generates. These are the numbers you will test.

3️⃣ Your ERP and production data, including the bill of materials (BOM) for each finished good. This is what proves the inputs actually went into the products.

4️⃣ Your return-deadline clock: the legal period each temporary import has before it must be discharged, by merchandise type. For most inputs, Article 108 of the Ley Aduanera and the IMMEX Decree set an eighteen-month window.

5️⃣ Your regime and clave map: which clave de pedimento and which régimen each operation ran under, so you can confirm the system recorded what actually happened.

With those five on the table, the audit is four questions.

The reconciliation: prove every temporary import went somewhere legal

Start with entries. Every temporary import pedimento in your universe has to appear in the entries report, with the correct clave, fracción arancelaria, quantity, and regime. An import that cleared customs but never made it into the system is the simplest descuadre, and the one that grows silently, because nothing downstream flags it.

Then follow each entry to its discharge. This is the heart of the audit. Every quantity that came in temporarily has to leave through a documented path: a return or export pedimento, a change of regime to definitive with the contributions paid, a virtual transfer to another IMMEX operation, or a destruction or donation on the record. Anything not yet discharged has to sit in the balances report as a controlled pending-return item. Entries minus discharges must equal your balance, and your balance must match what is physically in the plant and in process. When those two numbers diverge, you have found exactly what an auditor is trained to find.

In our work across the corridor, the descuadre we see most often is not fraud and not even sloppiness. It is a discharge that happened physically but was recorded against the wrong entry, or an export pedimento that discharged a round number instead of the actual consumption. The goods moved correctly. The record did not follow. And a record that does not follow is, to the authority, indistinguishable from goods that never left.

Third, reconcile the bill of materials. The materials-used report is where your Anexo 24 proves that the inputs you imported temporarily are the inputs that went into the goods you exported, plus the mermas (waste) and desperdicios (scrap) the process legitimately consumes. This is the check that connects the customs record to the factory floor.

Common mistake: treating mermas and desperdicios as a rounding line. Waste and scrap are legitimate, but they have to be justified by the process and documented, not used as the plug that makes a BOM reconcile. An unexplained waste percentage that absorbs whatever the numbers need is one of the clearest signals that the input-output correlation is not real.

The risk clock: age your pending returns

Of everything in the audit, this is the check with a deadline attached, which makes it the one to run first if you are short on time.

Every item sitting in your balances report as pending return is running against a legal clock. Temporary imports do not stay temporary indefinitely. When merchandise passes the return window the law sets for it, it stops being a deferred obligation and becomes a due one: it is treated as if it had been imported definitively, and the contributions you deferred at entry come due, with surcharges from the date of the original import.

So age the balance. Sort your pending-return items by entry date, apply the return window for each merchandise type, and flag everything within ninety days of its deadline. Those items are your real exposure, and they are the ones a broker or an internal team can still act on. An input three weeks from its deadline is a task. The same input three weeks after it is a liability.

Quick check: pull your ten oldest open temporary-import balances right now and confirm each one is still inside its legal return period. If you cannot answer that in an afternoon, the aging is the audit to run before any other.

The timing test: is your system actually current?

The last question is not about the numbers. It is about whether the system that holds them is as up to date as the law says it has to be.

The baseline, under Article 59, fracción I, is that the control data is current at all times and available to the authority. A system that reconciles perfectly but only after a monthly batch process does not meet that standard, because on any given day between batches, the record does not reflect the operation.

For certified operations the bar is explicit. Companies registered under the Registro en el Esquema de Certificación de Empresas (the IVA/IEPS certification) fall under Apartado C of Anexo 24, which requires the system to be updated within forty-eight hours of the conclusion of the customs clearance. The small number of operations certified under the OEA rubro for the Sistema Electrónico de Control de Inventarios de Importaciones Temporales (SECIIT) work to a tighter twenty-four-hour standard with continuous online access for the authority. Know which standard applies to you, then confirm your system meets it, not in theory, but on a random Tuesday.

What "done" looks like, and when to bring in help

You have finished the audit when four things are true: every temporary import in the period is in the system, every entry is either discharged or carried as a documented pending-return balance, the bill of materials reconciles input to output including justified waste, and nothing is sitting past its legal return deadline. A signed reconciliation with zero unexplained variances is the artifact you want on file, because it is the same artifact that answers a requerimiento in a day instead of a month.

A single mismatched pedimento is a rectificación and a conversation with your customs broker. That is routine. The signal that you need more than a one-off fix is a pattern: discharges that consistently lag entries, a waste percentage that quietly grew to make the numbers work, pending-return balances aging past their windows, or a reconciliation that never quite closes month over month. When the problem is in the system rather than in one document, correcting one pedimento does not resolve the exposure. It postpones the finding.

That is the point to bring in a second set of eyes. A control system that does not reconcile is a documented cause for a requerimiento, and left unresolved, a path to the suspension or cancelation of the program the whole operation depends on. Across more than 190,000 customs operations a year at 39+ ports, the pattern is consistent: the operations that never face an Anexo 24 crisis are not the ones with the best software. They are the ones that run this reconciliation themselves, on a cadence, before anyone asks them to.

If you want a second set of eyes on yours, talk to a Joffroy expert about an Anexo 24 reconciliation review of your last sixty days.

TRADE. UNDER CONTROL.