A message for those who have been dragging their feet on complying with Mexico’s new import declaration law: Time’s up.

June 1 is the date on which Mexico begins enforcement of a comprehensive mandatory reporting law for all imports. For each shipment, the Manifestación de Valor Electrónica (MVE) customs value declaration requires importers to electronically file a commercial invoice, packing list, certificate of origin, proof of payment, insurance documentation and Carta Porte (bill of lading and legal proof of possession). All must be cross-referenced for consistency and uploaded to a Mexican government portal. Any discrepancy between invoice and bill of lading triggers a fine. And without a proper MVE, the shipment doesn’t move.

Mexico introduced the MVE last fall, twice extending the deadline for enforcement. Many importers took advantage of the reprieve to hold off on compliance. They can no longer do so, says Françoise Lavertu, co-founder of Desteia, provider of an artificial intelligence-driven platform for global trade.

Lavertu says the new law clamps down on filing mistakes, with 37% of import declarations currently containing errors. That’s less a result of deliberate misstatements than the arduous nature of the process. Mistakes might include an outright failure to submit, submission of the wrong types of documentation, incomplete files, or reporting of incorrect quantities or values. Given the sweeping nature of the requirement, importers can now be subject to a diverse set of fines, not to mention blockage of their shipments. Notably, the legal responsibility for submitting accurate documentation — and, as a result, fines imposed for errors — falls on the importer, not the customs broker that processed the paperwork.

Prior to now, Lavertu says, there was no formal system for assessing fines against errant importers into Mexico. Proper documents had to be submitted to customs and kept on file for five years, but “the sense of urgency was not there.”

Why now? The official line is that Mexico needed to gain tighter control over its import process. Lavertu adds that the measure promises to significantly boost revenues for the Mexican government in the form of new fees and fines. Yet another possible motive is a matter of timing: Enforcement of the MVE comes 30 days before the kick-off date for review and renewal of the United States-Mexico-Canada Agreement, and the government might want the MVE enshrined in law before the three countries start squabbling about one another’s trade practices. “It seems like a fortunate or unfortunate coincidence,” Lavertu says. “The context is definitely relevant.”

Mexican customs operates one of the world’s most advanced digital systems for submitting import documentation, Lavertu notes. But the sheer scale of goods crossing into the country can make compliance a huge headache for importers and their customs brokers — and the details contained in the MVE only exacerbate the challenge. “It’s opened up a Pandora’s box for some of our customers, [due to] the pure volume that teams have to manage,” she says.

There is an upside to the regulation, in that it forces importers to improve the accuracy of their trade documentation and quality controls. Bad data can add up to incur higher costs down the line. But the bigger the company, the greater the risk of non-compliance with the MVE. Those that stand to be most affected include U.S. multinationals with manufacturing and distribution operations in Mexico, consumer brands, retailers and, especially, automotive manufacturers. (That last sector currently accounts for the highest share of Mexico’s exports, with a total value of nearly $186 billion a year.)

For Desteia, the MVE presented an opportunity to offer an AI-driven platform for complying with the law. Dubbed Auto-MVE, it links up with the importer’s email inbox, interprets and validates documents in multiple formats, detects discrepancies, and builds the complete electronic file for transmission to Mexican customs. Lavertu says development of the tool was prompted by multiple customer requests for an automated means of complying with the MVE at scale.

The MVE isn’t the only new administrative burden to fall on importers into Mexico this year. Additional regulations being imposed by the country include a law that requires full documentation of a foreign entity’s machinery and operating capital, tied to its international commerce declaration, Lavertu says. Both importers and experts will be required to document the ”material reality” of their foreign trade operations in Mexico. That would require them to bring in their legal and H.R. departments to ensure compliance. There’s no fine for failure at the moment, Lavertu says, but companies “are telling us that this has a high risk of becoming a financially liable process.”