The annual tax return filing period is approaching in Mexico. If at the end of the year the taxpayer paid more income tax (ISR) than he should have, a so-called saldo a favor — positive balance in favor of the taxpayer. In this case, the SAT tax service is obliged to return the overpaid amount.
Most often, an overpayment occurs because the employer withheld more tax (retenciones) during the year than was ultimately necessary, or because when filing a return the taxpayer claimed personal deductions (deducciones personales), for example, medical expenses, education or mortgage interest, which reduce the final tax amount. After filing the annual return, the system recalculates the total liability and if the amount of withholding exceeds the estimated tax, a refund entitlement arises.
In Mexico, individuals file annual returns throughout the month of April. After filing your return, the IRS has up to 40 business days to process your refund. This is the maximum period provided by law. In practice, if there are no errors, returns are processed much faster, in most cases within 5 — 15 working days.
In other words, the sooner the declaration is submitted, the sooner the overpaid tax amount will be refunded. Taxpayers who file in early April are more likely to receive their refund earlier because the system processes applications as they are received. If you apply closer to the end of the deadline, the likelihood of a longer wait increases.
However, an automatic return is possible only if a number of conditions are met. The taxpayer must have up-to-date data in the system: a valid RFC tax number, a correctly registered bank account (CLABE) and an e.firma electronic signature. For amounts above a specified threshold (usually more than 10,000 pesos), the taxpayer identification requirements may be stricter.
It is worth considering that the tax service reserves the right to suspend the refund. Errors in bank details, mismatched account holder name, inactive tax status, or lack of a valid electronic signature can block the payment.
Tax history also has a significant impact. If there are obligations for previous periods or other obligations, the overpayment has the right to be offset against them.
Moreover, the system automatically checks the validity of the claimed deductions. It is important to note that not all expenses are eligible: deductions that do not qualify or are not supported by proper documentation (such as those without CFDI electronic invoices or paid in cash) may be rejected in whole or in part, which will impact your refund amount.
Return delays may be due to inconsistencies in preloaded information. If the system records income or sources of payments that do not match the taxpayer’s data, the return is transferred to an additional (manual) verification mode.
If the automatic refund is rejected, the taxpayer retains the right to re-apply. This may be either a corrective declaration (declaración complementaria) or submission of a request through the electronic return form (FED) with supporting documents attached.
So, the formal deadline for refunding overpayments under ISR in Mexico is up to 40 business days, but the actual speed depends on the quality of the data, tax history and the moment of filing the annual return. If the papers are prepared correctly, returns usually occur within the first two weeks after submission.