Lecturas > Contracts Executed Abroad and Their Tax Validity in Mexico.

On January 23, 2026, a relevant isolated decision was published in the Semanario Judicial de la Federación, addressing contracts executed abroad and their tax effects in Mexico.

This judicial criterion establishes that:

Private contracts executed abroad, when intended to produce tax effects in Mexican territory, must comply with the “fecha cierta” requirement under Mexican law.

The criterion arose from a case in which the tax authority denied a tax refund, arguing that the contract executed abroad lacked sufficient evidentiary value because it did not meet the “fecha cierta” requirement in accordance with Mexican legislation.

The Court upheld this position, stating that even if a contract is executed outside Mexico, when it is used to support tax effects within the country, it must comply with the requirements that make it enforceable against third parties, including the tax authorities.

Although this is an isolated decision, it constitutes a guiding criterion that may be relied upon by the SAT and by courts in matters related to:

• Tax deductions.
• Tax credits or refunds.
• Transactions with foreign suppliers or related parties.
• Tax audits and reviews.

The scope of this criterion is not limited to the specific contract analyzed, but may extend to any contract executed abroad that produces tax effects in Mexico.

Under Mexican civil law, a private contract acquires fecha cierta when:

• It is notarized before a public notary.
• It is recorded in the corresponding Public Registry.
• One of the signatories passes away.

In the absence of these elements, the tax authority may challenge the evidentiary value of the contract, even when the underlying transaction is real and properly carried out.

This criterion may be used by the SAT to challenge or deny tax effects derived from transactions supported by contracts executed abroad that lack a Spanish translation, do not evidence fecha cierta under Mexican law, or cannot be fully substantiated before the authority.

The impact may be particularly relevant in tax refunds, deductions and tax credits, especially in structures involving cross border transactions.

The publication of this criterion does not imply that all operations are immediately at risk, nor that existing contracts must be modified right away. However, a preventive review is strongly recommended, particularly for significant international operations, in order to anticipate potential challenges from the tax authority.

Specifically, we recommend:

• Identifying transactions with foreign parties or suppliers.
• Reviewing the contracts supporting such transactions.
• Confirming the availability of Spanish translations, when applicable.
• Assessing the convenience of certified copies or mechanisms to evidence fecha cierta.

Our legal team is available to review, on a confidential and case by case basis, transactions supported by contracts executed abroad and to define preventive strategies that strengthen your tax position in the event of a SAT review.