PROSEC and the Regla Octava: The Two Tariff Relief Instruments Most Importers Under-Use

In a plant outside Querétaro, a purchasing lead ran the numbers on a component the company had been importing from Asia for six years. Nothing about the part had changed. Nothing about the supplier had changed. The landed cost had moved by double digits, and the line item responsible was the Impuesto General de Importación (IGI). The company had an IMMEX program. It assumed IMMEX covered it. For the portion of production sold into the Mexican domestic market, it did not.

That gap is where two Mexican instruments live, and both are legal, both are decades old, and both are consistently left on the table. PROSEC (Programa de Promoción Sectorial) grants registered producers a preferential IGI rate on specified inputs and machinery, regardless of where those goods originate. The Regla Octava, the eighth complementary rule of the tariff schedule, lets an authorized company import parts, components and machinery under a single classification in Chapter 98 instead of under the higher lines that would otherwise apply to each piece.

Neither is a loophole. Both are registration and permit instruments, which is precisely why they go under-used: the paperwork sits between the company and the saving, and nobody owns it. This is the blueprint for closing that gap.

Why the arithmetic changed

Two decrees reset the baseline against which these instruments are measured.

The first, published in the Diario Oficial de la Federación on December 29, 2025 and in force January 1, 2026, modified 1,463 tariff fractions of the TIGIE, applying ad valorem rates ranging from 5% to 50% to goods originating in countries with which Mexico has no free trade agreement in force. Sectors hit include automotive and auto parts, steel, aluminum manufactures, textiles and apparel, footwear, plastics, chemicals, paper and paperboard, glass, appliances, furniture and toys.

The second, published on April 23, 2026 and in force the following day, modified 185 tariff fractions with rates from 5% to 35% and reformed Article 5 of the PROSEC Decree, specifically fracciones I, II inciso b) and XIX, which correspond to the electrical, electronics, and automotive and auto parts programs.

Read those two together and the operational conclusion is not that tariffs went up. It is that the gap between the general rate and the PROSEC rate widened at the same moment the eligible-fraction lists moved for three of the highest-volume sectors. The instrument became more valuable and more conditional in the same quarter.

What PROSEC actually is

PROSEC is established in the Decreto por el que se establecen diversos Programas de Promoción Sectorial, published in the DOF on August 2, 2002 and amended many times since. Article 3 creates twenty-four sectoral programs, among them the electrical industry, electronics, furniture, footwear, mining and metallurgy, capital goods, chemicals, rubber and plastic manufactures, steel, transport other than automotive, paper and paperboard, leather and hides, automotive and auto parts, textiles and apparel, and food.

The structure that matters operationally is two lists. Article 4 sets out, per sector, the finished goods a registered producer is authorized to make. Article 5 sets out, per sector, the tariff fractions of inputs, parts, components, machinery and equipment that producer may import at the preferential rate, generally 0% or 5% instead of the general rate.

The critical property is this: the PROSEC rate does not depend on origin. A free trade agreement lowers duty because of where a good comes from. PROSEC lowers duty because of who is importing it and what they will make with it. That is exactly why it is the primary lawful lever against a wall built on non-FTA origin. It is also why it is limited: the benefit belongs to producers, for goods in their authorized sector, destined to the finished goods that same sector covers.

Common mistake: treating PROSEC as a company-level exemption. It is a fraction-level, sector-level authorization. Importing an input that appears in Article 5 under a sector your company is not registered for is not a preferential import. It is an incorrect one.

What the Regla Octava authorizes, and why it is a different instrument

The Regla Octava lives in Article 2, fracción II of the Ley de los Impuestos Generales de Importación y de Exportación, among the complementary rules for interpreting and applying the tariff. It allows a company, with prior authorization from the Secretaría de Economía, to import in one or several shipments and through one or several customs offices the parts, components, machinery, equipment, packing materials and other goods required for its production, classified under the fractions of heading 98.02 rather than under the individual lines that would otherwise apply.

Two things follow from that, and both are routinely missed.

First, it is a permit, not a status. It is requested through the Ventanilla Única as an import permit, with a defined scope: specific goods, specific quantities, specific value, specific origin. The authorization number has to be declared on the pedimento. A permit that has lapsed, or that has been exhausted against its authorized volume, is not a permit.

Second, it runs on PROSEC. There is currently no active Registro de Empresa Fabricante, and the PROSEC authorization is what establishes the applicant's standing. The temporary-import modality additionally requires an IMMEX program; the definitive-import modality does not, which is the whole point for a producer serving the domestic market.

The clean way to hold the distinction: PROSEC changes the rate on a listed input. The Regla Octava changes how a set of goods is classified so it can be imported as what it functionally is, a production package, instead of as a collection of separately dutiable parts.

Where the saving actually shows up

Take a producer importing an input from a non-FTA origin at a general rate of 25% under the December 2025 decree, at two million dollars of annual import value. At the general rate that is five hundred thousand dollars of IGI a year. If the same fraction appears in Article 5 for that producer's authorized sector at 0%, the IGI line goes to zero. At 5%, it goes to one hundred thousand. The arithmetic is illustrative, not a quote, and the actual rate depends entirely on the fraction and the sector, but the order of magnitude is the point: on a single high-volume input, the annual delta routinely exceeds the entire cost of getting registered.

The other half of the saving is the one CFOs miss. Under IMMEX, the IGI on a temporary import is deferred, not extinguished. Change the regime to definitive, or sell the finished good into the Mexican domestic market, and the duty becomes payable at the rate then in force. A producer that exports everything may never feel the December 2025 decree. A producer that sells thirty percent domestically feels it on thirty percent of its inputs, and that is precisely the exposure PROSEC addresses and IMMEX does not.

Q: Most operations assume IMMEX already covers them. When does PROSEC actually change the number?
Daniel Sánchez, Customs General Manager, Joffroy Global

A: The moment any part of your production stops being exported. IMMEX is a deferral tied to return or export, so it works perfectly right up until a change of regime or a domestic sale, and then the deferred duty lands at the current rate. PROSEC is a rate reduction, so it holds in both directions. In practice we see three triggers: a company starts selling domestically, a company brings in machinery it intends to keep, or a company's input mix shifts toward a non-FTA origin. Any one of those is the signal to check whether your inputs appear in Article 5 for your sector.

The registration sequence

Getting registered is procedural, not complex. It follows a fixed order, and skipping a step is what produces the six-month version of a two-month process.

1. Classify the reality first. Identify the tariff fractions of the inputs, components and machinery you actually import, and the fractions of the finished goods you actually produce. Not what the ERP says. What clears.
2. Map both against the decree. Confirm your finished goods appear in Article 4 under a specific sector, and that your inputs appear in Article 5 under that same sector. Alignment across both lists is the eligibility test.
3. Confirm the list is current. Article 5 has been amended repeatedly, most recently on April 23, 2026 for the electrical, electronics and automotive programs. Verify against the consolidated text, not against a copy someone saved.
4. File the PROSEC registration with the Secretaría de Economía through the Ventanilla Única, for the sector or sectors that match. A company can hold more than one program where its production genuinely spans sectors.
5. Layer the Regla Octava only if you need it. If the value is in the rate, PROSEC alone does the work. If you are importing sets of parts, disassembled goods, or full production lines where classifying piece by piece is both expensive and impractical, request the 98.02 permit, with the modality that matches your regime.

What keeps the benefit alive, and what cancels it

This is the section that decides whether the saving is durable or temporary, and it is the one most registration projects treat as an afterthought.

The annual report is the single largest cause of avoidable loss. Article 8 of the PROSEC Decree obliges the program holder to report its prior fiscal year foreign trade operations to the Secretaría de Economía. It is filed through the Ventanilla Única as part of the Reporte Anual de Operaciones de Comercio Exterior (RAOCE), and the PROSEC deadline is the last business day of April, earlier than the IMMEX deadline under Article 25 of the IMMEX Decreto, which falls at the end of May. Miss April and the PROSEC program is suspended. Fail to cure it by the deadline the Secretaría publishes each year, and it is cancelled. The program otherwise renews on the strength of that report.

Beyond the report, the cancellation grounds are the ones you would expect from an instrument conditioned on productive use: breaching the decree or the terms of the authorization letter, ceasing to meet the conditions under which the program was granted, failing to file three or more of the required tax returns, changing fiscal domicile without notice to the Secretaría de Hacienda y Crédito Público, not being current on tax obligations, or destining goods imported under the program to purposes other than those Article 4 establishes.

That last one is the substantive risk, and it does not announce itself. Inputs imported at the PROSEC rate that end up in a product outside the authorized sector, or that are resold rather than transformed, are goods destined to a different purpose. The paperwork was correct. The use was not.

Quick check: pull the last twelve months of imports declared under your PROSEC number and confirm each fraction still appears in Article 5 for your authorized sector under the text in force. If your sector is electrical, electronics, or automotive and auto parts, that check should be run against the April 2026 version specifically.

Two more conditions worth holding. Permanence differs by regime: goods brought in additionally under an IMMEX program stay for the periods Article 108 of the Ley Aduanera sets, while goods imported definitively under PROSEC remain indefinitely. And the Regla Octava permit is finite in scope, so volume consumed against an authorization has to be tracked the same way any other balance is tracked.

Where to start

If your operation imports from a non-FTA origin and sells any portion of its output in Mexico, the first move is not a registration application. It is a two-column exercise: your top twenty imported fractions by annual value in one column, the general rate and the applicable PROSEC rate for your sector in the other. The gap between those two columns, multiplied by volume, is the number that tells you whether this is a compliance project or a margin project.

Across more than 190,000 customs operations a year at 39+ ports, the pattern in this specific area is consistent. The companies that capture these instruments are not the ones with the largest trade departments. They are the ones that treated PROSEC eligibility as a question with an answer, ran the mapping once, and then put the April report on a calendar that somebody owns.

Tariffs move. The instruments that offset them are stable, documented, and sitting in a decree that has been public since 2002. The only variable is whether your fractions are on the list, and whether anyone in your organization has checked this year.

Talk to a Joffroy expert about a PROSEC and Regla Octava eligibility mapping for your current input base.

TRADE. UNDER CONTROL.