In brief
On 23 October 2026, the Mexican President published a decree amending several provisions of the Customs Law. The amendments, which will become effective on 1 January 2027, significantly expand the circumstances in which customs authorities may seize imported goods on a precautionary basis due to declared value.
Most notably, customs authorities will be able to seize goods when the value declared in the import entry (pedimento) is lower than the transaction value of identical or similar goods determined under the Customs Law. Unlike the current rule, the amended provision does not establish a minimum percentage difference as a condition for seizure.
In more detail
Ex officio audits and precautionary seizure based on declared value
One of the most relevant changes concerns Articles 144 and 151 of the Customs Law.
Under the new second paragraph of Article 144, section XII, customs authorities will initiate their auditing powers ex officio when the value declared in the pedimento is lower than the transaction value of identical or similar goods determined under Articles 72 and 73 of the Customs Law (which are based on the Customs Valuation Code of the World Customs Organization and provide the alternative valuation methods of Transaction Value of Identical and Similar goods).
A similar standard is incorporated into Article 151, section VII, for precautionary seizures. In contrast with the current provision, the amended language eliminates the 50% undervaluation threshold and the exception for goods subject to estimated prices when the corresponding guarantee has been posted.
Importantly, under the amended law the comparison is not made against an estimated or reference price. Rather, the statute refers specifically to the transaction value of identical or similar goods determined under the valuation methods set forth in the Customs Law.
In practice, this change may be particularly relevant for importers whose legitimate commercial arrangements result in prices below those observed by the authorities for comparable merchandise. This could include, for example, related-party transactions, volume discounts, differences in commercial level or other pricing arrangements that affect the transaction value.
There is, however, an important transitional rule. Before 1 January 2027, the customs authorities will issue general rules identifying the types of goods that will become subject to precautionary seizure if the declared value is below that of identical or similar goods and explaining how the measure will apply. For goods not specifically listed, the rules will establish a percentage threshold based on the difference
between the declared value and the transaction value of identical or similar goods. If that threshold is exceeded, the authorities may initiate a precautionary seizure.
Releasing seized goods: Deposits, valuation evidence and the four-month deadline
The reform also changes the rules for substituting a precautionary seizure when the goods are not subject to estimated prices established by the Ministry of Finance and Public Credit ("SHCP").
Article 154 provides two scenarios, depending on the difference between the declared value and the transaction value used for comparison. In both cases, the importer has 10 business days from notification of the commencement of the administrative procedure to request substitution of the seizure:
- Difference below 20%. The importer may substitute the seizure by making a cash deposit or a deposit in a customs guarantee account. The amount must equal the import duties and countervailing duties that would be payable on the difference between the declared value and the transaction value used for comparison.
- Difference of 20% or more. The importer may also request substitution, but only through a cash deposit for the corresponding amount. The customs guarantee account alternative is not available in this case.
The mechanics for making these deposits will be established through provisions to be issued by the competent customs authorities (presumably the Foreign Trade General Rules issued by the Tax Administration Service).
Temporary imports
Under the amendment to Article 177, section XII, an infraction will be presumed if, during an audit, the customs authority determines that the value declared in the Pedimento or other customs document is at least 20% lower than the transaction value of identical or similar goods determined pursuant to Articles 72 and 73, provided that, had the goods been definitively imported, such undervaluation would have resulted in the total or partial omission of import duties or countervailing duties.
Hydrocarbons and petroleum products
Finally, Article 185 is amended to establish substantially higher penalties for certain violations involving hydrocarbons and petroleum products. In those cases, the applicable fine will range from 50% to 100% of the commercial value of the goods.
What importers should consider before 1 January 2027
The amendments to the Customs Law will become effective on 1 January 2027. As a result of these amendments, importers should pay particular attention to:
- Supporting the declared customs value with contemporaneous documentation
- Identifying related-party, discounted and high-volume transactions that may generate lower values
- Reviewing the documentation available to support adjustments or differences in commercial level
- Assessing the ability to provide a cash deposit or use a customs guarantee account within the 10-business-day period
Monitoring the general provisions that must be published by 31 December 2026, as these rules will determine important aspects of how the new seizure authority will operate in practice
Call to action
Further guidance will be important in assessing the full impact of these amendments, particularly the general provisions governing the application of Article 151, section VII.
Please feel free to contact us if you would like to discuss the specific steps your company should consider in preparation for the implementation of these measures, as well as potential legal avenues to challenge them based on your particular circumstances and operations. We would be pleased to assist you in assessing their impact and preparing for these changes.