The trap most foreign businesses fall into: you can do everything right — pay a supplier that looks completely legitimate, receive a normal invoice, and deduct it like any other business expense — and still get caught. If Mexico later flags that supplier as a fake-invoice seller, the problem becomes yours: the tax office can reach back several years and undo the deduction, and you often only find out during an audit. The reassuring part — a quick check today keeps you clear of it, and it's free.
What is an EFOS? The plain-English version
An EFOS — known locally in Mexico as the seller side of a fake-invoice scheme — is, in plain terms, a shell company that sells fake invoices. It bills other businesses for sales or services that never actually happened, so those businesses can use the paperwork to lower their taxes. In other countries you'd call it a "shell company" or an "invoice mill."
That's really all you need to remember. From here on we'll mostly skip the local jargon and just call it what it is: a fake-invoice seller on Mexico's tax blacklist.
In one sentence: a fake-invoice seller issues paperwork that looks legitimate so other businesses can write it off — but there was no real deal behind it.
Here's the part that matters most for you: the problem doesn't stop with the company that issued the invoice. If your business — as the customer — used one of those invoices to lower its taxes, the tax authority can come after you instead. That's exactly why it's smart to check your suppliers and clients from time to time. It takes minutes, and it's free.
The customer side — that's you
If a fake-invoice seller is one side of the deal, the other side is the customer who used the invoice — the business that wrote it off to reduce its income tax or claim back its sales tax. In Mexico this side is called an EDOS, but you don't need the term. What matters is who it usually refers to: an ordinary, legitimate business — quite possibly yours — that paid a supplier and used the invoice in good faith.
And here's the reassuring part: being on the customer side is not an accusation. If you genuinely received the goods or services, that is your defense. Keeping a little proof of each deal — and checking your suppliers now and then — is usually all it takes to stay safe.
| The fake-invoice seller | The customer (likely you) | |
|---|---|---|
| Who it is | A shell company that sells fake invoices | A real business that used the invoice to lower its taxes |
| What they do with the invoice | Issues it / sells it | Writes it off (deducts it) |
| Usually acting in | Bad faith — that's the whole business | Good faith — often didn't know |
| Local name in Mexico | EFOS | EDOS |
Don't worry about memorizing "EFOS" and "EDOS" — they're just the local labels for the seller and the customer. We'll stick to plain English.
How a company ends up on the blacklist
The tax authority doesn't blacklist a company at random. It starts the process when it spots a clear warning sign — usually one of these two:
No real way to do the work
The company billed for goods or services it had no real capacity to deliver — no staff, no equipment, no premises, no way to produce or ship what the invoice describes. The numbers simply don't add up to a real business.
Nowhere to be found
The company can't be located at its registered address. When the authority goes looking and there's no one there, that reinforces the suspicion that the deals were never real.
Just one of these is enough for the authority to open the case and flag the company — a stage often described as "presumed," meaning suspected but not yet proven.
For the curious: the law behind the blacklist is Article 69-B of Mexico's tax code. You don't need to know it to protect your business — your Mexican tax advisor or our Spanish pages have the exact statutes.
What happens next, step by step
Once a company is flagged, the process follows a clear timeline — and the dates matter to you, because they tell you how much time you'd have to react. Here's how it unfolds:
The company is notified
The tax authority tells the flagged company in three places: its official online inbox, the tax authority's website, and the government's official gazette (in Mexico, the DOF — the public record where official notices are published).
15 days to clear its name
The flagged company has 15 days to send in evidence and prove the deals were real, with a one-time short extension available if it needs a little more time.
The authority reviews and decides
Once the evidence is in, the tax authority weighs it and decides whether the company cleared its name or not.
The confirmed blacklist is published
If the company didn't clear its name, it's added to the confirmed list at least 30 days after the decision. From then on, its invoices no longer count for taxes.
Why the timing matters: while a supplier is only flagged, its invoices still count — but the clock is running. If it gets confirmed and you didn't notice, the deductions you took are suddenly at risk. Quietly watching the list for you is the difference between heading off a problem early and finding out too late.
The 4 stages a company moves through
A company on the list (identified by its RFC — a Mexican company's tax ID, like a business tax number) can move through four stages. Knowing them helps you read the list at a glance:
| Stage | What it means for you |
|---|---|
| 1. Presumed (flagged) | The company has been flagged and is suspected, but it can still clear its name. For now its invoices still count — though this is your early warning to take a closer look. |
| 2. Cleared | It proved its deals were real and was cleared. Nothing to worry about here. |
| 3. Confirmed | It couldn't clear its name. Its invoices no longer count for taxes. This is the stage that matters if you used one of them. |
| 4. Cleared on appeal | It challenged the decision in court and won, so it's removed from the confirmed list. |
What "confirmed" really means
Once a supplier is confirmed on the list, the deals behind its invoices are treated as if they never happened — and that applies backward in time, too. So it's not only future invoices that are affected; the ones you already wrote off can be questioned as well. That's the part worth keeping an eye on.
A quick heads-up: Mexico has more than one blacklist
If someone mentions "the SAT blacklist," it's worth asking which one — because there's more than one, and they're easy to mix up:
| List | What's on it |
|---|---|
| The tax-debt list | A separate list of companies with unpaid tax debts, companies that can't be located, and similar situations. It's not about fake invoices. |
| The fake-invoice list | The one this page is about: fake-invoice sellers, and the customers who used their invoices. |
This page is only about the fake-invoice list — the one that can affect deductions you took from a supplier. If you're ever unsure which list someone means, your Mexican tax advisor can tell you in a moment.
Why this matters when you're new to Mexico
If you run a foreign-owned company in Mexico — or an IMMEX / maquiladora operation, or you import and export — you're probably leaning on a network of local suppliers you can't vet as closely as you would back home. That's completely normal, and it's nobody's fault. But it's also where the exposure quietly sits: a single supplier ending up on the confirmed blacklist can mean lost deductions, back taxes and fines for your business — no matter how careful and legitimate your own operation is.
You can inherit this without choosing it
Your business can do everything right and still get caught up in this, simply because a supplier you paid turns out to be a shell company. And because the authority can look back at earlier years, a supplier that seemed perfectly fine when you worked with it can still cause trouble if it's confirmed later. The reassuring news: checking your suppliers before you pay them — and keeping half an eye on them afterward — is the cheapest, simplest protection there is.
What to do if a supplier of yours gets blacklisted
First, don't panic — you have options, and a clear window to act. Here's what it looks like:
Your 30-day window
If a supplier you used lands on the confirmed list and you'd written off its invoices, you have 30 days from the confirmed listing to do one of two things:
- Show the deal was real: prove you genuinely received the goods or services — contracts, delivery records, bank payments, emails, that kind of everyday paperwork.
- Adjust your filings: correct the affected tax returns yourself.
If the window passes without action
If you don't show the deal was real and don't adjust your filings, the tax authority can cancel those deductions and ask for the unpaid tax plus interest and fines. You can see the full picture in risks and penalties of using fake invoices.
The easiest path is prevention. Keep a little proof of each deal as you go (contracts, delivery records, bank payments), and let us watch your supplier list for you so you hear about it the same day a supplier appears. Catching it early is far easier — and far cheaper — than sorting it out after the fact.
Common questions
What is an EFOS, in plain English?
It's a shell company that sells fake invoices — invoices for goods or services that were never delivered — so other businesses can use them to lower their taxes. Mexico's tax authority puts these companies on a public blacklist. "EFOS" is just the local Mexican name for them.
Who actually gets in trouble — the seller or the customer?
Usually the customer who used the invoice — which could be your business. If you wrote off an invoice from a supplier that's later blacklisted, your deduction can be cancelled. The good news: if the deal was genuinely real, that's your defense.
When does Mexico flag a company?
When it billed for work it had no real way to do — no staff, equipment or premises to deliver what the invoice describes — or when the company simply can't be found at its registered address.
How long does a flagged company have to defend itself?
It has 15 days to send in evidence and clear its name, with a short one-time extension available. The authority then decides, and the confirmed list is published at least 30 days after that.
What happens once a supplier is confirmed on the list?
Its invoices no longer count for taxes. If you used any of them, you have 30 days from the confirmed listing to prove the deal was real or correct your filings.
Is this Mexico's only blacklist?
No — there's also a separate list for unpaid tax debts and companies that can't be located. This page is about the fake-invoice list specifically. Check your suppliers against it here.
Last updated: June 2026. This page is here to help you understand the topic — it's friendly background, not formal tax or legal advice. For your own situation, a qualified Mexican tax advisor is your best friend.