Mexico Targets Customs Undervaluation With Strict New Reforms

Mexican President Claudia Sheinbaum has submitted a legislative proposal to reform the country’s Customs Law as part of the Economic Package for 2027, marking the second consecutive year the executive branch has sought to strengthen custom regulations.

The initiative, sent to the Chamber of Deputies, introduces amendments to Articles 144, 151, 153, 154, and 177. The primary objective of the proposal is to intensify the government’s crackdown on merchandise undervaluation, enhance tax and tariff collection, and protect domestic manufacturers from unfair competitive conditions. However, trade experts, tax specialists, and business representatives warn that the stricter rules threaten taxpayer rights, risk supply chain bottlenecks, and increase administrative burdens for compliant importers.

Under current legislation, customs authorities are only permitted to initiate the precautionary seizure (embargo precautorio) of imported goods when the declared value is underreported by 50% or more compared to the transaction value of identical or similar merchandise, as calculated via statutory valuation methods.

The executive branch argues that this 50% threshold severely restricts preventative regulatory action, preventing customs officials from seizing shipments even when substantial discrepancies exist between declared values on import declarations (pedimentos) and legal valuation baselines.

According to figures from the National Customs Agency of Mexico (ANAM), between January 2025 and August 2026, authorities identified 2,541 import operations valued at MX$1.587 billion (US$92.56 million) that fell below legal reference values but could not be seized because the declared undervaluation was under the 50% mark.

To close this gap, the reform completely eliminates the 50% threshold. Under the revised text of Article 144, customs authorities will automatically initiate verification powers (facultades de comprobación)—including home visits and audit reviews—whenever the declared value of a shipment is lower than the transaction value of identical or similar goods by any amount.

"Now the fact that the imported value is lower by any amount compared to the value of similar merchandise already gives rise to starting an Administrative Customs Procedure (PAMA), even if it is one peso below the reference value used by the authority," said Gloria Estrada, a member of the foreign trade commission at the College of Public Accountants of Mexico.

Estrada criticized the aggressive nature of the bill, warning that customs authorities rely on internal databases to set comparative values, creating room for official discretion.

"It is a very aggressive reform that tightens regulations and makes compliance harder for all taxpayers. They can compare the imported value of a cheap brand of watches with the value of previously imported watches from more expensive brands, and from there determine an alleged undervaluation. It is a reform that does not distinguish, where the innocent will pay for the guilty, because at any moment any import could fall into a presumption of undervaluation," Estrada said.

Under the proposed modifications to Article 154, when goods are not subject to estimated prices, importers faced with valuation discrepancies—whether under 20% or equal to or exceeding 20%—may request to substitute a precautionary seizure by making a cash deposit into a guarantee customs account (cuenta aduanera de garantía). This request must be submitted within 10 business days following notification of the procedure, and the deposit must cover potential duties and compensatory tariffs resulting from the price difference.

Amendments to Article 153 clarify that if an importer successfully submits evidence verifying that the declared value is correct and compliant, authorities must resolve the proceeding, release the merchandise, and return the guaranteed funds.

Industry leaders caution that these changes could disrupt port operations. Eduardo Díaz, vice president of the Customs and Trade Facilitation Commission, ICC Mexico, warned that expanding seizure triggers risks overwhelming customs facilities.

"We could be facing scenarios of massive merchandise seizures at customs that will definitively slow down import processes. We could face significant saturation in customs warehouses, because all that seized merchandise has to be stored somewhere prior to clearance. What is concerning is that this threshold is completely eliminated," Díaz said.

Díaz noted that the reform fails to account for legitimate commercial discounts, such as volume purchases or inventory clearances, as well as corporate ties and importer track records.

Omar Cerón, partner, Dorantes Advisors, added that while the bill seeks to curb underreporting, it disproportionately burdens existing compliant taxpayers without addressing illicit smuggling.

"It creates a lot of noise to know how these specific actions are really going to achieve these effects. Whether putting an excessive control will really cause importers to understand—in the case of all those who have engaged in undervaluation—or simply find other mechanisms, other ways to execute it, bringing merchandise in at a lower value," Cerón said.