Mexico publishes customs law reform against undervaluation, effective January 2027

On October 23, Mexico’s Official Gazette (DOF) published, in its evening edition, the decree amending articles 144, 151, 153, 154, 177 and 185 of the Customs Law. This completes the legislative process: the Chamber of Deputies passed the reform on October 6 and the Senate on October 13. The decree takes effect on January 1, 2027.

The main change concerns valuation. If the value declared on the pedimento is below the transaction value of identical or similar goods, customs will open a review on its own initiative. That same condition is now enough for a precautionary seizure, without the fixed 50% threshold the law used to require. To replace a seizure, importers can post a cash deposit or use customs guarantee accounts when the gap is under 20%; at 20% or more, only a cash deposit is accepted.

For hydrocarbons and petroleum products, inaccurate, incomplete or false declarations will carry fines of 50% to 100% of commercial value. Customs authorities must publish, by December 31, 2026, the rules that set which goods and which percentages the seizure regime will apply to.