What Is the Foreign Trade Complement?
The foreign trade complement (complemento de comercio exterior) is an annex to the CFDI that Mexico's tax authority, the SAT, requires when a Mexican company makes a definitive export and that merchandise is sold. Unlike a regular invoice, this complement adds the customs entry (pedimento) data, the agreed Incoterm, and a detailed description of each exported good, so the invoice and the customs filing stay linked in a single document.
If your company exports and only issues a "regular" CFDI without this complement, the invoice is incomplete in the eyes of the SAT and can trigger findings in an audit or delays at customs clearance. That's why it helps to know, from the very first shipment abroad, when it applies and what data it requires.
When Is the Foreign Trade Complement Mandatory?
The complement is mandatory when two conditions are met at the same time: the operation is a definitive export under pedimento key A1, and there is a sale (enajenación) of the merchandise. Pedimento A1 is the key Mexico's customs system uses to identify merchandise leaving the country permanently, with no intent to return.
There's an extra case many companies overlook: the complement also covers definitive A1 exports where the merchandise isn't sold, or is given away at no charge. For those cases there's a specific node that records the reason for the transfer instead of sale data, so "there was no sale" isn't a valid reason to skip the complement when the pedimento is A1.
If your business exports under other pedimento keys, such as temporary imports or returned merchandise, that CFDI doesn't carry this complement; different CFDI 4.0 rules apply there, and it's worth checking those with your accountant before invoicing.
Who Has to Issue the Complement, and What the Customs Broker Does
Responsibility for generating the CFDI with the foreign trade complement falls on the exporter, not the customs broker: it's the company selling and invoicing the merchandise that has to stamp the receipt with the complete filing data. The customs broker (agente aduanal), for their part, is the one who files the pedimento with customs and holds key data — the pedimento number, the tariff classification, the regime key — that the invoicing team needs to fill out the complement correctly.
In practice, that requires close coordination between the foreign trade team handling the pedimento through the customs broker and the team issuing the CFDI: if the pedimento is stamped after the invoice goes out, or the data isn't shared in time between the two, it's common to end up with a CFDI that doesn't match what was declared to customs. Automating that data exchange is exactly what cuts down that risk.
Required Fields on the Foreign Trade Complement
Beyond the data any CFDI already carries, the complement adds information specific to the export filing:
- Pedimento key, which in this case must be A1 (definitive export).
- Certificate of origin, when a free trade agreement applies.
- Incoterm agreed with the foreign buyer, which defines who bears the costs and risks of the shipment at each stage.
- Complete fiscal data for the issuer, per the current SAT catalog for this complement.
- Foreign recipient's data, including their address and, when applicable, their tax ID number in the destination country.
- Description of the merchandise, including its tariff classification (fracción), quantity, unit of measure, and value in US dollars.
- Reason for the transfer, required only when the export doesn't involve a sale or is given away at no charge.
Every one of these fields has to match what was declared on the customs pedimento; a mismatch between the CFDI and the pedimento is exactly what tends to trigger the most problems in a review.
Common Mistakes When Filling Out the Foreign Trade Complement
The errors that come up most often when generating this complement follow a clear pattern:
- Using the wrong pedimento key, entering a key other than A1 for a definitive export, or leaving the field populated with data copied by mistake from a previous pedimento.
- An Incoterm that doesn't match the sales contract agreed with the buyer, which creates inconsistencies between the invoice and the deal's documentation.
- Incomplete foreign recipient data, such as leaving out their address or tax ID number in the destination country when the pedimento requires it.
- Generic merchandise descriptions, without the correct tariff classification or the level of detail customs requires, which makes it hard to cross-check the CFDI against the pedimento.
- Skipping the transfer-reason node on exports without a sale, on the mistaken assumption that the complement only applies when a sale is involved.
- Not validating the CFDI against the SAT's current catalogs before stamping, which can trigger rejections over invalid pedimento keys, units of measure, or tariff classifications.
Foreign Trade Complement vs. Carta Porte vs. Payment Complement
It's easy to confuse the foreign trade complement with other CFDI annexes, but each one answers a different need. The Carta Porte complement proves the physical transport of merchandise within or out of the country and documents the route, the carrier, and the vehicle; the foreign trade complement, by contrast, documents the export transaction itself for the SAT and customs, with pedimento and foreign-buyer data.
It shouldn't be confused with the payment complement either, which is issued when an invoice is paid in installments or after it was originally issued: that complement has nothing to do with exports or customs pedimentos — it's about the moment the money is actually received. A single export transaction can require, at different points, the foreign trade complement when invoicing and, if applicable, Carta Porte for the shipment itself.
How to Automate Foreign Trade Complement Filing
Manually entering every field of the complement — pedimento key, tariff classification, Incoterm, foreign recipient data — for dozens or hundreds of exports a month is a steady source of human error, exactly the kind that causes the most trouble with the SAT and customs.
Automating CFDI issuance with the foreign trade complement lets you pull data from the pedimento and the export order directly from your internal systems, validate it against the SAT's current catalogs before stamping the invoice, and generate the receipt without anyone transcribing each field by hand. That cuts both the risk of a rejected invoice and the time your foreign trade team spends on administrative work instead of operations.
Frequently Asked Questions
Does the foreign trade complement apply to every export?
No. It only applies to definitive exports under pedimento key A1. Other customs operations, like temporary imports or returned merchandise, follow different rules and don't carry this complement.
What if I export merchandise without charging for it, like a sample or a donation?
You still need to issue the complement if the pedimento is A1. It includes a specific node to record the reason for the transfer on operations without a sale or given away at no charge.
How often does the foreign trade complement change?
The SAT periodically updates CFDI complements, including their catalogs and technical structure. Before stamping an invoice, it's worth confirming with your invoicing provider or on the SAT's portal that your system uses the current version and catalogs, instead of assuming your current setup is still valid.
Does the foreign trade complement replace Carta Porte?
No. They're different documents for different purposes: the foreign trade complement documents the export transaction for the SAT and customs, while Carta Porte proves the physical transport of the merchandise. A single export can require both.
What happens if the pedimento and the CFDI don't match?
It's one of the most common reasons for findings in customs and tax reviews. The complement's data — pedimento key, tariff classification, quantities — has to match exactly what was declared to customs.
If your company exports regularly and wants to stop relying on manual entry for the foreign trade complement, at AISDC we build CFDI invoicing systems that generate this complement with pedimento data validated before stamping, integrated into your existing foreign trade operation.