Some people spend years in the wrong tax regime without realizing it. A self-employed professional in PFAE who qualifies perfectly for RESICO and pays two or three times more ISR than necessary. A contributor in RESICO whose income has already exceeded $3.5 million and who is accumulating a tax debt without noticing. Or someone who wanted to make the change in March because "January was too busy" and had to wait another twelve months.
Your tax regime is not an administrative label — it defines what percentage of your income goes to SAT, which monthly obligations you must meet, what expenses you can deduct and how complex your accounting needs to be. Switching regimes at the right time can mean tens of thousands of pesos per year. Doing it wrong, or not doing it when you should, carries consequences ranging from overpaying taxes to fines for non-compliance with the obligations of the previous regime.
SAT only allows a regime change once per calendar year, in January. If you did not do it in January 2026, the next opportunity is January 2027 — unless you start or conclude a different economic activity, which is the only valid exception.
The main regimes for individuals
Before getting into the change process, here is the map. Individuals in Mexico can be registered under different regimes depending on their activity type and income level. They are not interchangeable at will — each has entry and permanence requirements.
| Regime | For whom | ISR rate | Income limit |
|---|---|---|---|
| RESICO | Individuals with business activity or professional services | 1% – 2.5% on gross income | Up to $3,500,000 MXN per year |
| PFAE (Business Activity) | Entrepreneurs, merchants, complex service operations | Progressive ISR table (up to 35%) | No limit |
| Honorarios (Professional Services) | Independent professionals: doctors, lawyers, consultants | Progressive ISR table (up to 35%) | No limit |
| Rental Income | People renting out real estate | 35% on net profit (or 20% flat on gross income) | No limit |
| Employees | Workers under employment relationship (employer withholds ISR) | Progressive table (withheld by employer) | No limit |
The same taxpayer can have income from multiple sources simultaneously: employee plus professional fees, or rental plus business activity. The regime that "changes" when you submit the request to SAT is the one tied to your primary registered activity.
When a switch makes sense — and when it does not
From PFAE or Honorarios to RESICO
This is the most frequent change since RESICO came into effect in 2022. RESICO rates range from 1% to 2.5% on gross income, which for many professionals and small business owners is significantly less than the progressive ISR table.
It makes sense when: your income does not exceed $3.5 million annually, you do not have high deductible expenses (because in RESICO you cannot deduct them), and your activity is not excluded from the regime.
It does not make sense when: you have significant operating costs — office rent, salaries, materials — that under PFAE would reduce your taxable base below what RESICO would charge. In those cases, despite RESICO's lower rate, you can end up paying more because you cannot subtract the expenses.
From RESICO to PFAE or Business Activity
The most common scenario: income has grown and is approaching or exceeding the $3.5 million ceiling. This also happens when the taxpayer wants to invoice under more complex structures, formally hire employees or deduct expenses RESICO does not allow.
What many do not know: if your income exceeds $3.5 million under RESICO, SAT has the authority to move you automatically to the Business Activity regime. That automatic change can come as a surprise with retroactive obligations that were not met. The prevention is to make the voluntary change before crossing that threshold, with an accountant planning the transition.
Adding a secondary regime
Sometimes it is not a pure "change" but an addition. If you are an employee and start providing professional services independently, you can add the Honorarios or RESICO regime without removing the employee one. Declarations are filed combined. This is one of the procedures that generates the most errors because people do not know they must register the activity before starting to issue invoices.
Who CANNOT enter RESICO
Article 113-E of the LISR establishes the exclusions. Some points that surprise those trying to enter the regime:
- Partners or shareholders in legal entities (personas morales) — if you own shares in an active SA de CV or SRL, you cannot be in RESICO as an individual for that activity
- Those earning income from commissions or brokerage when these exceed 30% of total income
- Taxpayers with income exceeding $3.5 million in the previous year
- Those with establishments abroad
Having past tax debts with SAT is not by itself an exclusion from RESICO, but it can affect the outcome of the change procedure if there are pending notifications in your tax mailbox.
How to make the change online
The procedure is officially called "Actualización de actividades económicas y obligaciones" and is done through the SAT portal:
- Log in at sat.gob.mx with your RFC and SAT password (or with your e.firma if the system requires it).
- Go to "Trámites" → "RFC" → "Actualización de actividades económicas y obligaciones".
- On the update screen, you will see your current activities and regimes. Select the regime you want to remove and the one you want to add.
- The system will automatically validate whether you meet the requirements of the target regime. If there is a restriction, the reason will appear.
- Confirm the change. The new regime becomes active from the month following the request.
- Download and save the acknowledgment receipt — it is your proof of the change.
The online procedure works well for straightforward changes between PFAE and RESICO. If you have multiple activities, pending debts, or the system shows an unexplained error, going in person to a SAT Administration can resolve in the same day what can get stuck online.
What changes — and what does not — from the following month
Once approved, the following month you start meeting the obligations of the new regime. That includes updated monthly declaration mechanics, updated CFDI type if your invoicing structure changes, and updated ISR monthly payment platform in SAT.
What does not change retroactively: the prior fiscal year closes under the regime you had. If you made the change in January 2026, the annual declaration for 2025 is still filed under the previous regime rules. This confuses many taxpayers who assume the change also affects the closing year.
The change SAT makes without asking you
For exceeding the RESICO income threshold. If your annual declaration or provisional payments show that you exceeded $3.5 million, SAT can automatically move you to Business Activity. The problem is not the change itself — it is that if you did not anticipate it, you were already operating under a different fiscal logic the previous month and differences in your obligations may arise.
For inconsistencies between declared activity and CFDIs issued. If your invoices show activity that does not match your registered regime, SAT may initiate a review and propose a correction. In both cases, having an accountant who monitors accumulated income and anticipates the threshold crossing is worthwhile — the cost of reacting late exceeds the cost of preventive advisory. See our accounting services and how we work.
Common mistakes that complicate the change
Making the online change without verifying it was registered. The SAT portal sometimes shows a success screen but the change is not reflected in the Constancia de Situación Fiscal. Always download the updated certificate the following day to confirm.
Not deregistering the obligations of the previous regime. If you moved from PFAE to RESICO but did not cancel the PFAE obligations (monthly declarations, DIOT if applicable), you will keep receiving SAT requirements for those missing filings. Changing the regime and updating obligations are two separate procedures.
Changing in February thinking it applies to January. The change takes effect the month after the request. If you do it on February 15, the new regime starts in March. January and February remain under the previous regime.
Are you in the right regime for your situation?
We review your activity, current income and expenses to determine which regime benefits you most in 2026. If a change makes sense, we handle it. If not, we explain why. Service in Spanish, English and Russian.
Free consultation →Frequently asked questions
Can I change regime more than once a year?
Generally no — one change per calendar year. The only exception is starting or concluding a specific economic activity. If you stopped providing professional services and started a different commercial activity, you can update when that change of activity actually occurs. But attempting two regime changes for the same activity within the same year is not permitted.
What happens to my CFDIs issued under the previous regime?
They remain valid. There is no need to cancel or reissue them. CFDIs show the issuer's tax regime at the time of issuance, which is correct. What changes going forward is the regime that appears on new CFDIs issued after the change.
Do I need the e.firma to make the online change?
For many changes, RFC and SAT password are sufficient. However, if the system detects inconsistencies or the change involves more sensitive activities, it may require authentication with the e.firma. If yours has expired or you do not have one, the online procedure may not let you complete it and you will need to go in person to a SAT office.
Does changing regime mean getting a new RFC or e.firma?
No. The RFC does not change — it is the same tax identifier for your entire tax life. The e.firma is also unaffected by a regime change. The only thing that updates in SAT is your Cédula de Situación Fiscal, which reflects the new regime.
If you have multiple income types or a more complex situation, before making the change it is worth calculating how your ISR will be computed under the new regime and which personal deductions will still apply. A well-calculated switch can have a positive impact from the very first month. See our monthly accounting plans for individuals under all regimes.