If you have a tax refund due to the SAT (Mexican Tax Administration Service) and are considering requesting a refund of income tax (ISR) or value-added tax (IVA), you need to know that the rules have changed. In 2026, the tax authority will require more thorough documentation than in previous years, applying more rigorous audits to curb tax evasion. The result is a significant increase in the rejection of automatic refunds and a greater requirement for complete documentation—trial balances, CFDI (electronic tax receipts), and bank statements—to authorize any refund. Incomplete documentation, suppliers with high-risk profiles, or simple inconsistencies in your bank details are sufficient reasons for the SAT to deny your request, even if everything appears to be in order.
At GGAF — Guajardo Abogados y Asesores Fiscales, we assist businesses and individuals in Monterrey in recovering their tax refunds from the SAT (Mexican Tax Administration Service), compiling robust documentation and managing each procedure with the rigor required by the 2026 tax environment. Learn more about our accounting services.
Why is the SAT rejecting more refunds in 2026?
The fundamental change has a name: materiality. The SAT (Mexican Tax Administration Service) no longer simply checks whether an invoice meets the formal requirements of the CFDI (Digital Tax Receipt); it now requires taxpayers to conclusively demonstrate that the transaction actually occurred, that there was a genuine economic exchange, and that the suppliers involved had the operational capacity to provide the services they invoiced. Added to this is the SAT's Master Plan, which intensifies oversight of taxpayers with patterns historically used to simulate transactions, beginning in 2026. The practical result is that the tax authority can detect inconsistencies that previously went unnoticed and use them as grounds to deny or delay refunds.
Changes to VAT refunds
VAT refunds are facing the most rigorous scrutiny this year. The Mexican Tax Administration Service (SAT) has significantly increased its preventative audits of this tax, particularly for taxpayers with zero-rate VAT or investment projects. In these cases, the authority requires the correct completion of the Informative Declaration of Transactions with Third Parties (DIOT) and supporting documentation for all payments through electronic receipts; cash payments are simply not eligible for credit.
Additionally, restrictions related to companies listed in Article 69-B of the Federal Tax Code—known as EFOS or companies that issue invoices for simulated transactions—are applied more rigorously. If the taxpayer or any of their suppliers has ties to these companies, the SAT (Mexican Tax Administration Service) will automatically reject any request for an expedited refund, regardless of whether the CFDI (Digital Tax Receipt) is formally valid. Therefore, the general rule in 2026 for VAT refunds is to process them from the beginning using the Electronic Refund Form (FED), attaching the supporting documentation and complete XML files. Failing to do so from the outset only prolongs the process and increases the likelihood of rejection.
Restrictions on income tax refunds for individuals
For individuals, one of the most significant changes in 2026 concerns the type of electronic signature required, depending on the amount of the tax refund. A simple password is only valid for amounts below the threshold established by the SAT (Mexican Tax Administration Service); above a certain threshold, an electronic signature (e.firma) is mandatory. Submitting the application with the incorrect signature will immediately halt the process.
Another critical point is the deadline: the automatic refund in the annual tax return has a defined window that closes on July 31st, so waiting too long could mean losing this benefit and having to manage the process manually. If the system detects discrepancies in personal deductions or declared income, the automatic refund is denied, and the taxpayer is required to request a manual refund, uploading all the corresponding supporting documents and XML files.
What you should have in order before requesting your refund
Regardless of whether your procedure is for ISR or IVA, there are three elements that must be correct before starting any procedure with the SAT.
CLABE account: must be an active 18-digit account, mandatory to be registered in the name of the holder with the SAT; any inconsistency in this data stops the deposit automatically and is the most frequent cause of rejection.
SAT Tax Mailbox: This is the only channel through which the SAT sends information requests, and a request not answered within the 20 business days period may result in the definitive dismissal of the procedure.
Materiality file: contracts, photographs, logs, deliverables and emails that prove that each operation actually occurred; this file must be compiled when the contract is signed, not when the request has already arrived.
To begin your application, track its progress, or consult the official forms, you can go directly to the Procedures and Services section of the SAT website. In cases of unjustified refusals or delays exceeding the 40 business days established by law, Prodecon offers free advice and the possibility of filing a formal complaint with the tax authority.
Is your refund at risk? GGAF can help
The 2026 tax environment leaves no room for improvisation. At GGAF — Guajardo Abogados y Asesores Fiscales, we are an accounting and tax firm based in Monterrey specializing in protecting our clients' assets and optimizing every financial decision. We compile materiality reports, validate supply chains, manage procedures with the Mexican Tax Administration Service (SAT), and support you through every requirement to prevent a rejection from becoming a permanent loss.
If you have a credit balance and don't want to risk it, schedule a consultation with our team. We'll analyze your situation, identify risks, and design the right strategy to recover what's rightfully yours.
This article is for informational purposes only and does not constitute specific tax advice. For specific situations, consult a certified public accountant.
