I. Platforms are no longer merely ”channels,” but rather nodes in the tax administration process.

Following the implementation of Mexico’s tax reform in 2026, digital platforms are explicitly required to fulfill five functions:Identify transaction parties, collect taxpayer information, withhold applicable taxes, issue tax receipts, and report transaction data to the tax authoritiesThe

This means that the tax authorities will cross-check the following information from the platform’s backend:

• Legal Entity Name for Store Registration
• Linked RFC Tax ID
• Bank Account Holder
• Actual Sales Data

In other words, the risk exposure associated with the traditional ”three-way separation” structure—where a store is registered under Company A, its RFC is held by Company B, and payment for goods is received through Company C’s account—is rapidly increasing. If discrepancies are found during a cross-check, the consequences will extend beyond simply paying back taxes; they may also result in the suspension of the store, the freezing of funds, and retroactive tax assessments for past periods.

II. The Cost of Not Having an RFC: How Was 36% Calculated?

According to the platform’s currently published automatic deduction rules, the deduction rate depends on two variables—the RFC status and the location of the receiving account—and is generally divided into four tiers:

| Seller RFC Status | Receiving Account | VAT Withholding | Income Tax Withholding | Total | |—|—|—|—|—| | Valid RFC in Mexico | Local Mexican Account | 8% | 2. 5% | 10.5% | | Valid Mexican RFC | Foreign Account | 16% | 2.5% | 18. 5% | | Valid Foreign Tax Registration Number | Any | 16% | 0% | 16% | | No Valid RFC Provided | Any | 16% | 20% | 36% |

The 36% category is non-deductible and non-refundable....which would directly eat into most of the profits from cross-border business. Even with an RFC, there is still an 8-percentage-point difference between local and offshore accounts—which is why many sellers, after obtaining an RFC, continue to evaluate the option of opening a local Mexican bank account.

It is important to clear up a common misconception: the terms “2.5%” and “20%” used here refer to the income tax (ISR) platform.WithholdingThe rate does not represent the final tax burden; the law explicitly stipulates that the ISR withheld by the platform at a rate of 2.5% may be used to offset subsequent monthly estimated tax payments or annual income tax. Similarly, the ”50% withholding” for Value-Added Tax (IVA) does not equate to a halved tax rate—the transaction still generates the full 16% in VAT, and the platform merely collects a portion of it on behalf of the taxpayer.

III. Relying on Someone Else’s RFC Is a Deal That Doesn’t Add Up

Using a third-party local RFC appears to immediately reduce the comprehensive withholding to 10.51 TP3T, but the risk profile is entirely different:

• Tax ID canceled or expired → Store may be permanently deactivated
• Audit and comparison revealed a mismatch in the account holder → Account funds were frozen
• The retroactive period for Mexican taxes can be up to 5 years. → Back taxes must be paid, along with penalties and late payment charges.

The registration and compliance costs saved in the early stages are far less than the losses incurred by a single retroactive audit. This is particularly evident against the backdrop of stricter audit standards in 2026—false tax addresses and shell offshore entities will be rejected even if all required documents are submitted.

IV. Four-Step Self-Assessment Checklist

Step 1: Verify the consistency of the entity. List the entity for the store registration, the entity for the RFC tax number, and the entity for the payment account in a single table. For any discrepancies, indicate the reason and a timeline for correction.

Step 2: Verify the validity of the RFC. Log in to the SAT portal to verify whether your tax ID is valid and whether there are any records of suspension or cancellation.

Step 3: Evaluate the structure of the receiving account. If there is already a valid RFC but payments are still being received through an overseas account, estimate the VAT savings that could be achieved by switching to a local account and compare them with the costs of opening and maintaining the account.

Step 4: Strengthen the evidence supporting the substance of the business. Documents such as the location where the contract was signed, the client’s location, and the location of the operations team serve as the basis for addressing subsequent audits.

In addition, documents issued overseas (such as certificates of incorporation, articles of incorporation, proof of director status, and powers of attorney for tax representatives) typically require notarization, Hague Apostille, or consular certification, as well as a sworn Spanish translation by a certified Mexican translator; ordinary translations are generally not accepted.Specific application requirements are subject to the official announcements by the SAT.

Qicaiying Group can assist cross-border sellers with RFC planning in Mexico, notarization and authentication of offshore entity documents, setup of local bank accounts, and monthly tax filings. If you’d like to conduct a compliance review of your existing structure, please contact us for a customized solution.