Mexico Customs Overhaul Could Seize Cross-Border Freight Over 20% Value Gaps

When would Mexico's new customs seizure threshold take effect?

Mexican President Claudia Sheinbaum submitted proposed amendments to Mexico's Customs Law (Ley Aduanera) to the Chamber of Deputies on September 8, with a committee vote expected as early as next week. If approved by Congress and enacted, the amendments would take effect the day after publication in Mexico's Diario Oficial de la Federación. The legislation would drop the value-difference threshold for precautionary seizure from 50% to 20% for goods entered under customs regimes in which duties are calculated but not immediately paid.

The proposal aims to combat undervaluation (declaring imported merchandise below its actual value to reduce duties and taxes), but critics warn it could expose cross-border shipments to more inspections, documentation requirements, and precautionary seizures. For U.S.-Mexico cross-border carriers, the biggest practical question is how aggressively Mexico's National Customs Agency (ANAM) uses the expanded authority if the legislation becomes law.

What the 20% threshold means for cross-border freight

Under current law, Mexican customs authorities can initiate precautionary seizure when an importer's declared value falls 50% or more below the transaction value of identical or similar merchandise. The proposed amendments would reduce that threshold to 20% for goods entered under certain customs regimes.

The legislation would also remove the existing 50% undervaluation threshold associated with precautionary seizure in certain other circumstances, giving authorities greater ability to detain imported merchandise over questions about its declared value. Authorities would first have to conduct a valuation analysis under procedures established by the Customs Law.

Mexican lawmaker Roberto Albores Gleason posted on Facebook that more than 2,500 customs operations valued at about $89.6 million currently escape precautionary seizure because of the existing 50% threshold.

How importers can replace or lift a precautionary seizure

The legislation proposes changing how importers can replace or lift a precautionary seizure. For value differences of less than 20%, an importer could generally use a cash deposit or customs guarantee account. Differences of 20% or greater would generally require a cash deposit.

Another provision would allow customs authorities to carry out precautionary seizures when an inspection identifies objective evidence suggesting irregularities in the declared value of goods that are not already subject to estimated prices established by Mexico's Finance Ministry. Authorities would first have to conduct a valuation analysis under procedures established by the Customs Law.

What documentation cross-border carriers will need

Greater scrutiny of customs valuation could mean importers need substantially stronger documentation supporting transaction values, particularly for related-party transactions, royalties, assists, and transfer-pricing adjustments. Trade law firm Sandler, Travis & Rosenberg said those areas are likely to receive greater scrutiny under the proposal.

For manufacturers, importers, customs brokers, and logistics providers operating between the U.S. and Mexico, the expanded authority raises compliance costs and the risk of freight delays when shipments are detained.

Just-in-time manufacturing disruption risk

Gilda Varela, director of customs and foreign trade for Mexico's automotive industry association (AMIA), warned that eliminating the existing 50% threshold could disrupt just-in-time manufacturing if automotive components are seized while valuation disputes are resolved, according to El Universal.

Representatives of bonded warehouses also raised concerns about congestion, storage costs, and insufficient space if precautionary seizures increase.

The Chamber of Deputies' Finance and Public Credit Committee held a working session Tuesday with officials from ANAM and representatives of private industry, according to La Jornada. The committee is now preparing a draft opinion on the legislation. La Jornada reported that lawmakers were expected to circulate the committee's draft opinion Wednesday and could vote on it next week.

What the proposal means for cross-border compliance

The administration argues that undervaluation erodes Mexico's import-tax base while placing domestic manufacturers at a disadvantage against goods entering the country at artificially low declared values. The proposal comes as Mexico continues tightening enforcement across its ports and land-border gateways.

The customs initiative was formally referred September 9 to the Finance and Public Credit Committee for consideration. As of Wednesday, the proposal remained at the committee stage and had not been approved by the full Chamber of Deputies.

For cross-border carriers, the practical takeaway is that stronger valuation documentation will be critical if the legislation passes. Carriers hauling automotive components, electronics, or other high-value goods under just-in-time schedules should prepare for the possibility of increased inspections and precautionary seizures at Mexican ports of entry. Importers should review their customs valuation procedures now, particularly for related-party transactions and transfer-pricing adjustments, to avoid detention and storage costs if the 20% threshold becomes law.