Mexico's 2027 tax reform: ISR withholding for software sales

The contract was signed in July. The service was delivered in August. The Mexican client booked the expense when the quarter closed. In January, when its finance team closes the fiscal year, nobody collected the ISR withholding on that payment, and the entire expense stops being deductible. Nothing about the operation changed, the software was delivered, the invoice was paid. What changes is who carries the risk on that line, and since September 8, 2026 that risk has a proposed address.

ISVs (Independent Software Vendors, software companies that sell their product to other businesses) selling into Mexico operate today on a comfortable premise: the tax obligation on the cross-border payment belongs to the client that pays, and the foreign vendor only has to issue the invoice. The 2027 Economic Package (Paquete Económico 2027), submitted by the Mexican Executive to the Chamber of Deputies on that September 8, moves that premise on two fronts at once, if approved as proposed: it ties the deduction of the payment to the withholding actually being collected, and it pulls forward the moment the withholding becomes due. If approved as proposed, the initiative's transitional provisions point to January 1, 2027.

What the 2027 Economic Package proposes, exactly

Two amendments are proposed, and they chain together. Today article 27, section V already conditions the deduction of a payment to a foreign resident on the withholding being made and remitted. The proposal does not create that condition, it ties the deduction to the fiscal year in which the payment of the consideration and the remittance take place.

Article 153, in turn, would set the withholding at the moment of enforceability, accrual, or payment, whichever occurs first. Read the two together, because it is the combination that creates the problem. What the initiative adds is not the condition, it is the condition's address in time. The deduction can no longer land in any later fiscal year and now depends on the year in which both things are satisfied.

The second provision is what changes the cash mechanics. The current text of article 153 requires the withholding to be remitted "on the date of enforceability or at the moment payment is made, whichever occurs first". The initiative adds a third trigger, accrual (devengo), the moment the expense is recognized for accounting purposes. A service delivered in August, paid in October, and booked in August now carries a withholding due in August, not in October. The window between the taxable event and the remittance shrinks, and the money has to be set aside earlier.

The Mexican regulatory analysis in this article is preliminary. It starts from the text of the initiative and from secondary sources that cite the document submitted to Congress. The wording can still change.

Caption: the three ISR withholding triggers and the deductibility condition by fiscal year. Proposed in the 2027 Economic Package, pending approval.

What happened on September 8, 2026

The Mexican Executive delivered the 2027 Economic Package to Congress on September 8, 2026, with the set of reforms that accompanies the Revenue Law. The initiative amends, adds, and repeals provisions of the LISR, and it folds tax incentives into the transitional provisions.

Two measures in the package decide the cost of selling software in Mexico, and both were drawn around the same stated goal: to discourage erosion of the tax base in cross-border and intra-group transactions.

The first is the article 27, section V reform already cited. The effect is a deferral, not a new restriction. The deduction is not lost, it changes fiscal year, and whoever satisfies both conditions in the same year loses nothing. The problem is operational, and it is large. The material describing the measure lists what the taxpayer needs to review in order to preserve the deduction: the contracts, the enforceability dates, the accounting record, the payment receipts, and the timely remittance. Five fronts, and not one of them is under the ISV's control.

The second is the article 153 reform, with the third trigger. Both are proposal, not law in force. As of this writing, the initiative had not been referred to committee or voted in the Union Congress. The text is still under review in the Chamber of Deputies, with the Hacienda Committee in permanent session, and the Revenue Law has a deadline of October 20, 2026.

The package also carries RESICO changes that widen the software market in the country, and they are worth knowing because they move the profile of the buyer. The initiative raises the revenue ceiling for individuals from 3.5 million to 5 million pesos and for legal entities from 35 million to 50 million, keeps the 2.5% top rate for individuals, and makes the regime optional for legal entities. If approved as proposed, the Revenue Law creates one of the proposed simplified VAT payment options, at 7%, for RESICO taxpayers, individuals and legal entities. The general VAT rate stays at 16%: this is not a rate cut, it is an optional payment regime with no right to a credit, and the gap between those two readings is wide for anyone calculating their own cost.

Why this matters more to the ISV than to the client

The ISV loses the deduction on the client's side, but it loses cash earlier, in the collection cycle, because the withholding falls due before it has been paid. That asymmetry is the center of the reform for anyone selling from outside, and it is easy to underestimate in a spreadsheet.

A royalty for the use of software pays today an ISR withholding of 25% on gross income, at the article 167, section II rate, which covers royalties distinct from section I and technical assistance. Double taxation treaties can reduce that rate, which is exactly why the structure of each sale matters. When the trigger moves to accrual, the client has to remit before it has paid the vendor. An organized buyer solves that with process. A disorganized buyer solves it another way: either it delays payment, or it disputes the withheld amount, and in both cases the ISV's receivables line takes the hit.

One distinction deserves attention here, because many treat it as a formality and here it decides the cost. The LISR separates payment for the use or enjoyment of software, which is a royalty and falls under article 167, from a pure software license without technology transfer, which is a distinct tax category and follows another path. They are not the same thing. A SaaS contract that bundles support, continuous updates, and platform access describes a provision of services. A perpetual license contract describes a grant of use. Collapsing the two into one calculation produces a comfortable number and a wrong one, and the error surfaces years later, on audit.

The Mexican market carries one more asymmetry that the reform sharpens. A buyer inside RESICO tends to carry fewer ancillary obligations and to have less tax infrastructure in place. When the deduction starts depending on a remittance that buyer may not know how to make, the vendor is the one who feels it, because the vendor is the one who misses the payment deadline.

Mexico is one piece of a larger picture. The map of the international ISV in Latin America shows why each country charges a different operational price for the same software, and the country-by-country SaaS compliance guide gathers the block of ancillary obligations that ISR withholding now becomes part of.

What changes in practice

The table below contrasts the rule in force today with the text proposed in the two provisions, and the third column answers the question the ISV asks first: who absorbs the bill. The final column is not decorative, because it shows that the risk has migrated out of the tax field and into operations.

Royalty and technical assistance coincide on the domestic rate of article 167, section II, but they remain distinct tax categories for treaty and contract classification purposes. A pure software license without technology transfer follows the third classification path, even though the domestic rate coincides, and that is why it appears on its own line.

In the ISV's case there is a second VAT layer, the withholding on digital services provided by non-residents (article 18-J of the LIVA), collected at source by the buyer or by the intermediary. That is not the 7% option, which sits on the Mexican side. It is the vendor's own exposure, and it exists today.

The position this table supports: the risk left the tax field and entered operations. If approved as proposed, the two provisions discussed here create no new tax. What they create is a dependency. And a cross-border dependency is working capital parked.

What to do now, before a possible January 2027 effective date

The window between the submission of the initiative and a possible effective date is the only period in which adjusting process costs no revenue, because nothing has fallen due yet. Five moves, ordered by return, begin with contract classification and end with the cash exposure of the transition quarter.

1. Classify every contract by its real object. Separate what is a royalty for the use of software from what is a pure software license without technology transfer, and from what is a provision of services. The classification sets the rate and sets who withholds. A contract portfolio review done now costs days; done on audit, it costs years.
2. Map the enforceability, accrual, and payment dates in every active contract in Mexico. The new trigger is the earliest of the three, so one date running ahead of the others is enough for the remittance to fall due on it. Contracts drafted with no enforceability clause are the most exposed case.
3. Check the position under the applicable double taxation treaty. The 25% rate of article 167, section II is the ceiling, not the sentence. The treaty between the vendor's country and Mexico can reduce the rate, and the reduction has to be documented with tax residence in order, not presumed.
4. Put the withholding in the contract as a named obligation, with proof. If the buyer's deduction depends on the remittance, the vendor needs a receipt, not a promise. The remittance receipt for the withholding is the document that closes that chain.
5. Review the cash exposure of the transition quarter. Fiscal year 2027 has one quarter in which contracts signed under the old rule start being performed under the new one, if it is approved as proposed. That quarter is where the money locks up. Anyone who has run that exercise in another market recognizes the shape: the cost of selling software in Brazil under fees, taxes, and an invoice is the same arithmetic under different legislation, and the structure of the problem does not change.

The channel, and what it solves in the problem above

Nothing on that list is hard to execute in itself. It is work, and the work lands on the vendor, which has no tax infrastructure in Mexico and does not need to build one in order to sell software there through the channel. The channel is the decision that solves this without opening an entity.

An international ISV that wants to sell into Mexico chooses between assembling that operation on its own, with a local entity and its own withholding process, or selling through a path that already exists. It is the same decision as the one between running your own operation and a model that already runs the tax side, and it precedes any discussion of rates. The direct path charges its known price: listing and review cycles, per-transaction fees, the contract and the program of whoever hosts the sale imposed on the vendor, a cloud commitment in order to transact, a foreign fiscal entity in order to receive, settlement in dollars with the FX and repatriation cost built in, and the entire compliance load carried alone, year after year.

The Nexforce Marketplace runs that path for the ISV. The solution this article is about is the second of the two Nexforce offers the international vendor: selling through a marketplace with Nexforce running that route. In practice, the ISV works with its own contract standard and its own programs, so its process does not change; it transacts with no commitment to any specific cloud; and the arrangement comes out cheaper for the vendor and for the end client, which are two calculations and not one. Local currency holds across all of Latin America, not just Mexico. Nexforce brings the reseller network and the software alliance, which generates savings on the buyer's other software spend to make the ISV's sale viable, a lever the vendor's own discount cannot reach. And there is the working capital asymmetry, which answers this article's problem directly: Nexforce pays the ISV upfront and installments the end client over up to 12 payments. The vendor carries no receivable, the buyer gets terms, and the withholding becomes an event the ISV does not have to chase, because the local operation is what executes it.

No cost to the ISV, no minimum deal size, and the region's payment methods, PIX, boleto, and local cards, in place of a dollar remittance. For anyone selling software from outside into Mexico, the 2027 problem is not the rate. It is the clock.

Frequently asked questions

Is Mexico's 2027 tax reform already in force? No. The 2027 Economic Package was submitted on September 8, 2026 and is still under review in the Chamber of Deputies. If approved as proposed, the effective date would be January 1, 2027, and the text can still change during the legislative process.

What changes in the ISR withholding for anyone paying a software vendor abroad? The proposal adds accrual to the triggers of the article 153 withholding, which today falls due on enforceability or on payment, whichever occurs first. If approved as proposed, the withholding also falls due at the moment the expense is recognized for accounting purposes, that is, on the earliest of the three triggers set out in the provision.

Does the deduction of the foreign payment cease to exist? No. Article 27, section V would require two conditions in the same fiscal year: payment of the consideration and remittance of the ISR withholding. Once both are met, the deduction happens. What changes is the fiscal year in which it is recognized.

Is the 7% VAT option a rate reduction? No. It is one of the proposed simplified payment options for RESICO taxpayers, individuals and legal entities, with no right to a credit. The general VAT rate stays at 16%, and the text still depends on approval.

Is software exempt from ISR withholding in Mexico? It depends on the object of the contract. Payment for the use or enjoyment of software is a royalty and falls under article 167, with a 25% withholding on gross income, subject to reduction by treaty. A pure software license without technology transfer is a distinct tax category and follows another treatment. The two do not add up and do not replace each other.

References and Further Reading

• Ley del Impuesto sobre la Renta, current text, Cámara de Diputados del H. Congreso de la Unión. Consolidated text of articles 27, 153, and 167, the basis for the contrast in this analysis.
• Ley del Impuesto al Valor Agregado, current text, Cámara de Diputados del H. Congreso de la Unión. The general 16% rate and the hypothesis for the importation of services.
• Reforma a la LISR 2027: nuevas reglas para intereses, pagos al extranjero, CUCA, CUFIN y estímulos fiscales, TaxToday México, September 11, 2026.
• Reforma a la LISR 2027: cambios al RESICO, deducciones y pérdidas fiscales, TaxToday México, September 10, 2026. Details the RESICO ceilings, the 2.5% top rate, and the optional character for legal entities.

The clock, not the rate

If approved as proposed, the 2027 Economic Package does not raise the tax burden on anyone selling software into Mexico. It changes the moment that burden becomes due and, in changing it, transfers to the foreign vendor a dependency it does not carry today.

The vendor collects well when the buyer remits well, and the two are now tied together in the same fiscal year. It is a small change in the legal text and a large one in the operation. Anyone selling software from outside into Mexico has until the end of the legislative process to decide where that tie falls. The decision does not wait.

The Nexforce Marketplace exists so that the tie falls on the side that knows how to run it: the end client gets terms and a tax invoice in local currency, the vendor is paid upfront, and the withholding clock stops being the ISV's problem.