Mexico's electronic value declaration starts October 1: what you transmit, what you don't

Mexico’s Electronic Value Declaration stops being optional on October 1, 2026. Through September 30, transmission via VUCEM remains voluntary; from October 1, it isn’t.

We covered that when the extension was published — what it is, who is responsible and how customs value is determined lives in the customs value declaration guide. This article is about the part of that same July 31 resolution almost nobody read: through December 31, 2026, you don’t have to transmit everything.

And that distinction — between what gets transmitted and what gets retained — is what will separate the importers who start October cleanly from the ones who jam.

The two temporary reliefs

Alongside the new deadline, the Second Resolution of Amendments to the 2026 RGCE set a transition regime running through December 31, 2026:

1. Not all supporting documents must be transmitted. The declaration and its valuation worksheet, yes; the complete file of documents backing every element, not necessarily.

2. A summary of contracts is accepted. Instead of transmitting in full the contracts or agreements related to customs value — sales contracts, distribution agreements, licences, royalty arrangements — a summary of them may be submitted.

The precise scope and which document falls under which case live in the resolution text and its annexes. Check the current version before building your process: this is exactly the kind of detail that shifts with each anticipated version.

What the relief does NOT mean

Here’s the expensive misunderstanding, stated plainly: the relief is about transmission, not about substance.

• The obligation to determine customs value correctly did not change. Valuation method, additions, relationship between the parties, royalties: all the same.
• The obligation to retain documentation did not change. The contracts you don’t transmit, you must hold, complete, available to the authority.
• Responsibility still sits with the importer. It didn’t move to the customs broker — not with the Customs Law reform, and not with this.
• Value enforcement did not loosen. Undervaluation remains a priority focus. Transmitting fewer documents doesn’t mean fewer operations get reviewed: it means the review arrives later, as a formal request.

Put differently: the resolution gives you less filing work in October. It does not give you less obligation.

And on January 1, 2027

The transition ends. From that date the full transmission scheme applies, with no contract summary and no documentary dispensation.

That turns the three months of relief into what they actually are: the time to assemble the file you’ll have to transmit in January. Anyone treating the relief as a mental extension will reach January exactly as unprepared, only without a safety net.

Who falls outside the requirement

Not every operation needs an MVE. Excluded, among other cases, are courier and parcel shipments valued under USD 2,500 cleared under simplified or consolidated entries.

If yours is formal cargo, assume it applies. The exceptions are narrow and worth verifying against the current text before building a process on top of them.

What you need technically

Five pieces. None of them can be obtained on shipment day:

1. A valid e.firma or digital seals. The transmission is signed. An expired e.firma stops the whole operation.
2. VUCEM access with the right user and permissions configured.
3. The valuation worksheet, showing the method applied and the additions itemized.
4. Express authorization to a third party, if you want your broker to consult or transmit on your behalf. Without it, the obligation stays with you, in full.
5. The supporting file, transmitted or not: invoices, evidence of payment, contracts, transport documents, insurance.

Five weeks: what to do with them

A plan that fits the time left:

• Week 1 — Inventory. List your recurring suppliers and sort them by valuation complexity: simple sale, related parties, royalties involved, framework contracts. The last three are where problems live.
• Week 2 — Contracts. Gather the current contracts for those suppliers and draft the summaries. Writing them now, calmly, is a different exercise from improvising with cargo at the port.
• Week 3 — Worksheet. Build the valuation template with one real case per supplier type. If you don’t know where an addition belongs, now is when that gets resolved.
• Week 4 — Live test. Transmit a voluntary MVE for an operation in progress. Transmission is voluntary through September 30: that window exists for exactly this.
• Week 5 — Process. Define who transmits, at what point in the flow relative to the entry, and what happens when that person is away. Document it on one page.

The mistakes October will surface

The usual ones, now with an electronic record:

• An expired e.firma discovered on clearance day.
• A broker authorization nobody granted, and an MVE nobody transmitted because each side assumed it was the other’s job.
• A declared value that doesn’t match the invoice or the payment. That used to surface in an audit; now it’s recorded instantly.
• Omitted additions — freight, insurance, commissions, royalties — because “they weren’t on the invoice”.
• Generic contract summaries that say nothing. A summary that doesn’t describe the actual relationship is worse than transmitting the contract: it puts in writing that nobody read it.

At TradeWay

We build the MVE process into the rest of the clearance — value determination, worksheet, file and transmission — so the declaration isn’t a loose errand but part of the same flow as the entry. One point of contact, one invoice. If you want to reach October with a tested process rather than a brand-new one, contact us.