Mexico has changed how its Customs Law treats undervalued imports. A decree published in the Diario Oficial de la Federación (DOF) on October 23, 2026 widens the cases in which customs can audit and seize goods because of their declared value, and it changes how an importer can get seized cargo back. The decree enters into force on January 1, 2027.
This article explains what the text says, who is exposed and what to prepare before the end of the year. It is general information, not legal advice. Reviewed on November 14, 2026.
What changed and from when
The decree amends or adds to six articles of the Ley Aduanera. The points that matter most to importers are these:
- Automatic audits (Article 144, section XII). When the value declared in the pedimento is lower than the transaction value of identical or similar goods, calculated under Articles 72 and 73, the customs authorities will open an audit on their own initiative.
- Precautionary seizure without the 50% threshold (Article 151, section VII). The text in force until the end of 2026 allows seizure only when the declared value is 50% or more below the value of identical or similar goods, unless a guarantee under Article 86-A has been provided. The new wording drops that percentage: a declared value that is simply lower becomes a ground for seizure.
- The detail comes in secondary rules. Under the second transitory article, the new seizure ground applies to the goods, and under the procedure, that the customs authorities define. For any other goods, the authorities may set the percentage of difference that triggers a seizure. Those provisions must be published in the DOF no later than December 31, 2026.
- New ways to replace the seizure (Article 154). For goods not subject to estimated prices, the importer has ten business days from notification of the start of the administrative procedure to ask that the seizure be replaced. If the declared value is less than 20% below the reference value, a cash deposit or a deposit in a customs guarantee account is accepted. If the gap is 20% or more, only a cash deposit is accepted. In both cases the amount equals the duties, taxes and countervailing duties on the difference in value.
- Getting the goods or the deposit back (Article 153). If the importer proves that the declared value was determined under the customs valuation rules of the law, the authority must issue its resolution immediately and without penalties, return the goods and release the guarantee or refund the cash deposit.
- Temporary and deferral regimes (Article 177, section XII). The undervaluation level that leads to a presumed customs infraction for goods entered under a regime that allows duties to be determined without paying them falls from 50% or more to 20% or more.
- Hydrocarbons and petroleum products (Article 185). From 2027, three sections of this article will carry a fine of 50% to 100% of the commercial value of the goods for these products.
Who is affected
Every importer of record in Mexico is exposed to the audit rule, because it applies whenever the declared value is below that of identical or similar goods. In practice, the companies with the most to review are:
- Importers buying well below market reference prices, even for legitimate reasons such as volume discounts, clearance stock, related-party pricing or long-term contracts. A low price is not an infraction, but from 2027 it must be provable.
- Companies using temporary import or other deferral regimes, because the 20% level in Article 177 applies to them specifically.
- Importers of the goods that the authorities list in the provisions due by December 31, 2026. Until that list is published, nobody can say with certainty which products will face seizure for any difference in value.
- Importers of hydrocarbons and petroleum products, who face the higher fines.
Freight forwarders and customs brokers are affected indirectly: a seizure for valuation stops the cargo, and storage and demurrage keep running while the importer gathers evidence. We covered the cost of that kind of delay in Most Common Mistakes When Importing into Mexico.
What to do now
There are about seven weeks between the date of this article and January 1, 2027. These steps do not depend on the pending rules:
- Build a valuation file for each recurring product. Purchase order, contract, commercial invoice, proof of payment, price list or quotation, and any document that explains a discount. The goal is to show that the price actually paid is the transaction value.
- Check that the Incoterm and the invoice tell the same story. Freight, insurance and other charges that form part of the customs value must be consistent with the agreed term. If you need a refresher, see our Incoterms guide.
- Compare your declared values with identical or similar goods. Ask your customs broker which reference values they see for your tariff classification. If your price is clearly lower, document why before the shipment sails.
- Decide in advance how you would replace a seizure. If the difference is 20% or more, only cash is accepted. Know who in your company can authorize that deposit within ten business days.
- Review temporary import operations. Compare the values declared under deferral regimes against the 20% level.
- Watch the DOF in December. The list of goods, the procedure and any percentages will define the real scope of the reform.
For the general sequence of an import, from the importer registry to release, see Customs Clearance in Mexico: Step-by-Step Process. For the previous round of changes, see Mexico Customs Law 2026.
Frequently asked questions
When does the Mexican customs undervaluation reform take effect?
On January 1, 2027, according to the first transitory article of the decree published on October 23, 2026.
Can Mexican customs seize my goods just because my price is lower than a competitor's?
From 2027 a declared value below that of identical or similar goods becomes a legal ground for seizure, but only for the goods and under the procedure that the authorities define, or above the percentage they set for other goods. Those provisions are due by December 31, 2026.
How do I recover goods seized for undervaluation in Mexico?
There are two routes in the amended text. You can prove that the value was determined under the valuation rules of the law, in which case the authority resolves without penalties and returns the goods. Or you can request, within ten business days, that the seizure be replaced by a deposit while the procedure continues.
Does the reform change how customs value is calculated?
No. The decree does not amend the valuation methods. It changes what the authority can do when the declared value is lower than the reference value of identical or similar goods.
How Flux Forwarders can help
Flux Forwarders coordinates international freight with a network of agents and licensed customs brokers. We can review with you whether the documents behind a shipment are consistent before it moves. To talk through an upcoming import, contact us or request a quote.
