Mexican lawmakers could vote as early as next week on a customs overhaul that would strip away a 50% undervaluation threshold currently protecting more than 2,500 customs operations worth about $89.6 million from precautionary seizure — a change trade groups warn could disrupt just-in-time manufacturing across the U.S.-Mexico border.

President Claudia Sheinbaum submitted the proposed amendments to Mexico's Customs Law, the Ley Aduanera, to the Chamber of Deputies on Sept. 8 as part of the government's economic package for 2027. The bill was referred Sept. 9 to the chamber's Finance and Public Credit Committee, which held a working session Tuesday with officials from Mexico's National Customs Agency (ANAM) and private industry representatives, according to La Jornada.

Lawmakers were expected to circulate the committee's draft opinion Wednesday, with a vote possible next week. If Congress approves the measure, the amendments would take effect the day after publication in the Diario Oficial de la Federación.

The threshold changes

The legislation targets undervaluation — declaring imported merchandise below its actual value to reduce duties and taxes. The administration argues the practice erodes Mexico's import-tax base and disadvantages domestic manufacturers competing against goods entered at artificially low declared values.

The most consequential change concerns when customs authorities can detain imported merchandise over questions about declared value. Under the proposal, ANAM would gain broader authority to initiate verification procedures whenever it determines an importer has declared a value below the transaction value of identical or similar merchandise — removing the existing 50% undervaluation threshold associated with precautionary seizure in certain circumstances.

A separate provision would cut from 50% to 20% the difference-in-value threshold used to presume an infraction for goods entered under customs regimes in which duties are calculated but not immediately paid, El Financiero reported.

Authorities would also gain the power to carry out precautionary seizures when an inspection identifies objective evidence of irregularities in declared value for goods not already subject to estimated prices set by Mexico's Finance Ministry — provided they first conduct a valuation analysis under Customs Law procedures.

The proposal changes how importers can lift a seizure, too. For value differences below 20%, an importer could generally use a cash deposit or a customs guarantee account. Differences of 20% or greater would generally require a cash deposit.

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 50% threshold.

What it means for shippers

For manufacturers, importers, customs brokers and logistics providers moving freight between the U.S. and Mexico, the central question is how aggressively ANAM deploys the expanded authority if the bill becomes law.

Greater valuation scrutiny means importers will 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 heightened scrutiny under the proposal.

The implications reach beyond compliance desks. Gilda Varela, director of customs and foreign trade for Mexican automotive industry association AMIA, warned that eliminating the 50% threshold could disrupt just-in-time manufacturing if components are seized while valuation disputes play out, according to El Universal. For auto plants running tight production schedules on both sides of the border, a detained parts shipment is a line-stoppage risk, not a paperwork problem.

Bonded warehouse operators raised a separate concern: congestion, storage costs and insufficient space if precautionary seizures increase.

OmniTRAX adds Phoenix-area rail capacity

Away from the policy front, OmniTRAX is expanding its rail-served industrial footprint in Arizona, acquiring 25 acres in Casa Grande to serve growing manufacturing and nearshoring demand in the Phoenix region.

The property will provide industrial outdoor storage (IOS) and transload services for customers serving Phoenix and the broader Southwest. It sits near major industrial operators including Lucid, Hexcel, LKQ, Tractor Supply and Wright Asphalt.

OmniTRAX said demand for industrial outdoor storage in the Phoenix market is outpacing nationwide demand, with particularly strong activity around Casa Grande driven by advanced manufacturing growth and proximity to the U.S.-Mexico border.

The acquisition follows OmniTRAX's purchase of the Sonoran Valley Railroad and forms part of a $100 million commitment to build a national network of rail-served real estate properties offering supply chain services. The Casa Grande site also adds capacity along a freight corridor increasingly connecting Arizona manufacturing operations with Mexico, where nearshoring investment continues to drive demand for industrial and logistics space.

With the committee vote expected within days and enactment triggered simply by publication in the official gazette, cross-border shippers have little time to audit their valuation documentation before ANAM's enforcement powers potentially expand.