The table remains available in 2026
Some taxpayers may file federal provisional or final returns due on the 17th one to five business days later, based on the sixth numeric digit in their Mexican RFC. Article 5.1 of the 2013 Decree creates a targeted administrative facility, not a universal extension.
Foreign-owned Mexican companies often put the 17th on every monthly tax calendar. That is a sensible internal target, but the legal last day can differ for an eligible taxpayer. SAT continues to display an RFC-digit table in its current individual, RESICO, and corporate declaration services.
Original Fintax post explaining that a Mexican federal return deadline may vary with the taxpayer's RFC.
The authority comes from Article 5.1 of the Decree compiling tax benefits and administrative simplification measures, published on December 26, 2013. It covers federal provisional or final returns legally due on the 17th of the following month, including a taxpayer's own federal taxes and qualifying withholding remittances.
RFC sixth-digit business-day table
| Sixth numeric digit in the RFC | Deadline under the Decree |
|---|---|
| 1 or 2 | The 17th plus 1 business day |
| 3 or 4 | The 17th plus 2 business days |
| 5 or 6 | The 17th plus 3 business days |
| 7 or 8 | The 17th plus 4 business days |
Count business days
Do not add calendar days. Saturdays, Sundays, and applicable Mexican federal tax nonbusiness days do not consume the extension. Convert the rule into an actual date every month.
How to find the sixth numeric digit
The rule does not say the sixth character. Read the RFC from left to right and count only digits. In a standard individual or corporate RFC, the first six digits normally represent the birth or incorporation date, so the sixth number is often the last digit of the day. Use the full RFC shown on the official tax ID card and count it rather than relying on memory.
- Copy the RFC exactly from the Mexican tax ID certificate.
- Ignore letters and count numeric characters from left to right.
- Place the sixth number in the official table.
- Start from the 17th and add only applicable business days.
- Confirm that the taxpayer is not excluded and that the return is actually one due on the 17th.
- Check the payment line expiration and complete payment within the valid period.
A counting example
Assume the sixth numeric digit is 6, which gives three business days after the 17th. If the 18th is a Friday and there is no tax holiday, the counted days are Friday the 18th, Monday the 21st, and Tuesday the 22nd. The deadline is Tuesday, not Sunday. This illustrates the method; a live filing should use that month's official calendar and any special provision.
Returns the facility is designed to cover
SAT's current pages for individual business, professional, rental, and VAT returns and corporate provisional and final returns reproduce the table. The common scope is federal monthly tax due on the 17th, such as provisional ISR, final VAT, IEPS, and withholding remittances, depending on the taxpayer's registered obligations.
The facility changes the last filing and payment date for a covered return. It does not change the tax computation, reporting period, or documentary requirements, and it does not cure an incomplete return.
Do not apply this table to unrelated deadlines
| Obligation | Why the table should not be assumed |
|---|---|
| Annual income tax return | Its deadline is not the monthly 17th rule |
| IMSS or INFONAVIT contributions | Social security follows its own rules |
| State or municipal tax | Article 5.1 concerns federal tax returns |
| Information filing or notice with a fixed date | The facility targets provisional or final returns due on the 17th |
Taxpayers excluded by the Decree
Article 5.1 excludes several categories, including taxpayers within Article 32-A of the Federal Tax Code, taxpayers electing a certified financial-statement tax audit under Article 52, Article 32-H taxpayers, certain entities handled by specialized SAT units, the Federation and Mexican states, and federal decentralized agencies or majority state-owned companies.
An ordinary individual business often sees the facility directly in SAT's service. A large company, group, public entity, or taxpayer subject to a tax audit or information-on-tax-situation regime should complete the exclusion analysis before moving the treasury deadline.
Portal access is not legal eligibility
The system accepting a return after the 17th does not by itself prove that Article 5.1 applies. Keep a file showing the obligation, legal basis, sixth digit, business-day count, and exclusion review.
Filing and paying are two controlled events
When a return produces tax due, compliance also requires payment through a valid payment line. Filing on the final extra day and paying later can still lead to inflation adjustment and surcharges. Reconcile the return submission time, payment-line validity, and confirmed bank debit.
- Return acknowledgment with transaction number and date.
- Payment line generated for that return.
- Bank confirmation with amount, reference, and date.
- Workpaper identifying the sixth digit and business-day calculation.
- Exclusion review for a large, public, or otherwise complex taxpayer.
Common deadline errors
| Error | Consequence | Control |
|---|---|---|
| Using the sixth character | Wrong row is selected | Count digits only |
| Adding calendar days | Deadline is miscalculated | Use a tax business-day calendar |
| Applying the table to every obligation |
Frequently asked questions
Is this a new 2026 extension?
No. The facility comes from the 2013 Decree and SAT continues to display it in current services. The 2026 reference means its current use was verified and each 2026 calendar date must be calculated with business days.
Can both individuals and companies use it?
Potentially yes, when they file covered federal provisional or final returns due on the 17th and are not excluded. SAT publishes the table in services for both taxpayer types.
Does every taxpayer receive five extra days?
No. The sixth digit determines one through five business days, and eligibility must be confirmed first.
What if the 17th falls on a weekend?
The actual date must be calculated under applicable business-day rules. Document the calendar and confirm the date and validity shown in the SAT service and payment line.
Official sources and next control
Read Article 5.1 of the Decree, SAT's current service for individual returns from 2025 onward, and its corporate declaration service. Fintax's monthly return review guide shows how to preserve the acknowledgment and payment evidence.
