New Rules for the 2026 Era: What Exactly Has Changed?

On January 1, 2026, Mexico’s new regulations on withholding taxes by digital platforms officially took effect. The most significant change isIncluding legal entities in the scope of coverage for the first time. Prior to this, the platform’s withholding requirements primarily applied to individual sellers; following the implementation of the new regulations, sellers operating Mercado Libre stores as local Mexican companies are now also subject to the platform’s withholding requirements.

For sellers, determining how much has been withheld depends on just one factor: whether it is linked to the platform's system.Valid RFC Tax ID Numbers. An RFC is not simply a matter of ”having one”; tax ID numbers marked by SAT as expired, suspended, or with mismatched information are treated as nonexistent in the system.

At the same time, the platform’s obligations are also increasing:

• Providing real-time trading data to SAT in accordance with Rule 2.9.21
• Issue the corresponding CFDI voucher for the withheld amount

This means that tax payments are no longer a closed loop where ”sellers file their own returns and the platform is unaware,” but ratherPlatform Data Connected Directly to the Tax AuthorityThe

With RFC vs. Without RFC: A 25.5-percentage-point Gap

When you look at these three scenarios together, the differences are very clear:

1. Legal entities that provide a valid RFC: The platform deducts 50% IVA (i.e., 8%), plus 2.5% ISR, for a total of approximately 10.5%
2. No RFC or RFC has expired: The platform deducts 100% IVA (i.e., 16%), plus 20% ISR, for a total of approximately 36%
3. private seller: The ISR tax rate was raised from 1% to 2.5%

In other words, a single RFC tax ID determines whether an order leaves you with 89.51 TP3T or only 641 TP3T. This isn’t a matter of the size of the ”tax optimization window”; rather, it’sWill this business be viable?The issue. Based on the commission range circulating in industry media in Mexico (according to industry sources, approximately 8%–18%, approximately 14%–17% for Category 3C, subject to the platform’s official rates), the cumulative effect of these fees means that the lack of RFC status virtually erodes the entire gross profit.

The Two Most Common Pitfalls for Cross-Border Sellers

Even if a user already holds a valid RFC, the platform must still, in either of the following two situations, 100% IVA Automatic Deduction:

• Sales Proceeds DepositedOverseas Bank Accounts
• Goods from overseas sellers are inWithin MexicoComplete the Sale

These two conditions are quite clear: the tax authorities want to see that ”sales, payment collection, and tax payment” all take place within the same tax jurisdiction. Many Chinese sellers typically operate by having a local Mexican company accept orders while the payment is remitted back to accounts in China or Hong Kong; under the new regulations, the costs associated with this approach will rise sharply.

Therefore, the selection of payment channels must be addressed during the store’s initial design phase, rather than waiting until the cash flow is running smoothly to make adjustments.

Withholding does not mean the tax has been paid

One thing needs to be made clear: platform-mediated deductions are merelyAdvance Payment...does not mean you are already in compliance. The taxpayer is still responsible for handling the difference after withholding, deductible input taxes, and monthly and annual tax filings.

In practice, we recommend proceeding in the following order:

1. Verify RFC Status: Log in to the SAT system to verify that your tax ID number is valid and that your address and business activity description match your actual information, to avoid having your registration deemed invalid due to outdated information.
2. Rearrange the payment collection process: Assess the feasibility of setting up a local collection account in Mexico and determine whether the reduction in tax burden resulting from switching to local collection is worth the cost of funds management.
3. Archived Withholding CFDI: Download the direct debit vouchers from the platform each month, reconcile them with the order transaction history on a transaction-by-transaction basis, and use them as the basis for claiming tax credits.
4. Recalculate the Pricing Model: Include the withholding amounts for 10.5% or 36% as cost items in the selling price formula, rather than passively deducting them from net profit.
5. Set a Consistent Filing Schedule: Establish a schedule for monthly IVA/ISR filings and annual filings to avoid back payments and late payment penalties

Three Prerequisites for Registering an RFC

Registering an RFC isn't difficult in itself; the challenge lies in the decisions you make before registering:

• Main Form: The withholding tax brackets for individual sellers and corporate entities differ; for long-term operations, it is recommended to operate primarily as a corporate entity.
• Entity to Which the Tax ID Is Linked: The business entity operating the store, the entity registered with the RFC, and the entity holding the payment account must all be the same; discrepancies among these entities are likely to trigger risk control measures.
• Follow-up Reporting Capabilities: Once an RFC is registered, it creates an ongoing reporting obligation that must be handled by a local accountant or agency.

The problem for many sellers isn’t that they ”can’t register,” but rather that they lack the ability to file tax returns after registration, which results in a negative record with the SAT.

Qicaiying has an on-the-ground team in Mexico specializing in RFC registration and local tax filing, which can assist with applying for tax ID numbers, registering business addresses and business activities, filing monthly IVA/ISR returns, and verifying and archiving withheld CFDI documents. Specific solutions will be evaluated on a case-by-case basis depending on the seller’s corporate structure and payment receipt channels.