---
title: "Unreliable VAT payer: how to verify a supplier | Otrock"
description: "When you are liable for a supplier's VAT: unreliable payer, unpublished bank account. How to check a supplier in the VAT payer register and what to do next."
url: "https://otrock.cz/en/blog/unreliable-vat-payer"
updated: "2026-10-23T10:38:38+02:00"
---

AI helpers

# Unreliable VAT payer and unpublished bank account: how to check a supplier before you pay

**Ondřej Tóth**14. 10. 20268 min read

An unreliable VAT payer is a payer that the tax office has decided has seriously breached its obligations in the administration of tax. If you buy from it, you can be liable for the tax the supplier fails to pay. You can also be liable if you pay a supplier who is a VAT payer into an account that is not published in the VAT payer register. That is why you should check your supplier before every payment.

The article covers when liability for VAT is a risk, how to check a supplier by hand in a few minutes, and what to do if the check fails. If you would rather not check by hand, you can leave the check to a program: [invoice extraction](https://otrock.cz/en/invoice-extraction) with supplier verification does it for every document before you approve it for payment.

## Who is an unreliable VAT payer?

A company or sole trader does not become an unreliable payer automatically. Under Section 106a of Act No. 235/2004 Coll., on Value Added Tax, this is decided by the tax administrator, that is, the tax office. It does so when a payer seriously breaches its obligations relating to the administration of the tax.

The Financial Administration publishes the information that a payer is unreliable in the VAT payer register, which is available to anyone. But the status is not permanent. No earlier than one year after the decision becomes final, an unreliable VAT payer may apply for a decision that it is no longer unreliable. The tax administrator will grant it if the payer has not seriously breached its obligations for a whole year (Section 106ac). A supplier's status can therefore change in either direction, and checking it once at the first order is not enough.

The same register also lists bank accounts. When registering, a payer lists all the accounts it uses for business and decides itself which of them the Financial Administration will publish (Section 96). For you as a customer, what matters is the **published bank account**.

## When are you liable for VAT that the supplier does not pay?

Liability is governed by Section 109 of the VAT Act. Its current wording has applied since January 1, 2025, when it was rewritten by Act No. 461/2024 Coll. A payer who receives a taxable supply from another payer, or pays for it, is liable for the unpaid tax on that supply if it knew, or should and could have known, that the tax would not be deliberately paid. What counts is what you knew at the moment the obligation to declare the tax arose. If you pay only after delivery, the moment of payment is assessed as well.

Liability applies to customers who are VAT payers themselves and buy for their business, and the supplier must be a payer as well. If you are not a VAT payer, you do not face liability under Section 109 in ordinary trade. Special rules apply only in exceptional situations, for example for goods subject to excise duty.

The Act also lists situations in which it is presumed that you knew, or should and could have known, that the tax would not be paid (Section 109(2)). This is a presumption that you can rebut, but then you have to provide the evidence yourself. The presumption applies mainly in these cases:

- **The supplier is published as an unreliable payer.** The amount of the invoice does not matter.
- **You pay into an account other than the one the supplier has published.** This applies even to part of the payment, and again the amount does not matter.
- **The price differs quite obviously from the usual price, without an economic reason.**
- **You pay more in cash than the Act on the Limitation of Cash Payments allows.** The limit is currently CZK 270,000, and all cash payments to the same supplier within one day count toward it.
- **You pay wholly or partly with a virtual asset.**

The Act also adds transactions between related persons and purchases of fuel from a distributor that is not published as registered.

Older guides say that with an unpublished account, liability only arises for payments above twice the cash limit, that is, above CZK 540,000. That was true until the end of 2024. The current wording of the Act has no such threshold, so liability can apply even to an invoice for a few thousand CZK.

Liability does not mean you pay right away. The tax office must first seek the tax from the supplier. It issues a demand to the guarantor only when the supplier does not pay even after a reminder and the tax cannot be recovered from them. It may skip enforcement only if it is clear that enforcement would demonstrably achieve nothing. It may also issue the demand once insolvency proceedings against the supplier have begun (Section 171(3) of the Tax Procedure Code). And you are liable for the tax on a specific supply, not for all of the supplier's debts.

### Worked example (model figures): you can pay the VAT twice

An invoice for materials is for CZK 100,000 excluding VAT, the rate is 21%, so the total is CZK 121,000. You pay it into an account the supplier has not published. The supplier does not pay the tax, and the tax office cannot recover it from them. As guarantor, you may then be called on to pay CZK 21,000, the tax you have already paid the supplier once as part of the price.

## How do you check a supplier in the VAT payer register and in ARES?

Checking a supplier by hand takes a few minutes and needs no special software. Here is how:

1. From the invoice, write down the supplier's Company ID and tax ID, and the account number you are to pay into.
2. In ARES, search by Company ID to confirm that the company exists and that its name and registered office match the invoice. ARES also pulls data from the VAT payer register, so you will see whether the company is listed as a payer.
3. In the Registr DPH (VAT register) app on the Financial Administration's MOJE daně portal, search for the supplier by tax ID.
4. Check that the supplier is not listed as an unreliable payer.
5. Compare the account number on the invoice with the published accounts. Every digit must match, including the bank code.
6. Save the result, for example as a dated screenshot. It serves as proof that you checked the supplier.

Repeat the check when the invoice arrives and again just before payment. Several weeks can pass between these two moments, and in the meantime the supplier may become an unreliable payer or change its published accounts.

## What should you do if the check fails?

What to do depends on what exactly is wrong.

### The account on the invoice is not published

This is often an oversight: the supplier has a new account and has not had it published. Ask them to have the account published, or pay into another of their accounts that is published. Under Section 96(2), the payer itself decides which accounts are published. If the supplier insists on being paid elsewhere and the reason makes no sense to you, be careful.

### The supplier is an unreliable payer, or the account cannot be sorted out quickly

For these cases, the Act offers a special method of securing the tax under Section 109a. You send the tax on the invoice directly to the supplier's tax administrator, that is, its tax office, before anyone calls on you as guarantor. You then usually pay the supplier only the price excluding VAT. With the payment, you state the following, in the format published by the Financial Administration:

- the supplier's identification,
- the tax the payment is for,
- your identification as the recipient of the supply,
- the date the supply was made, or the date the supplier received the payment.

The money is credited to the supplier's personal deposit account and used only for its tax on this supply. In the worked example above, you would therefore send CZK 100,000 to the supplier and CZK 21,000 to its tax office. It is a good idea to agree on this in the contract, or at least tell the supplier in advance, so there is no dispute over the unpaid part of the invoice.

## How to check suppliers on every invoice without searching by hand

Checking by hand works while only a few invoices come in each month. When there are dozens and several people pay them, the check is easily skipped. That is why, with us, a program does the check as a fixed part of processing every document:

- **Send the document however suits you.** Take a photo of the invoice and send it to Telegram, forward it by email or upload it on the website. AI reads the supplier, Company ID, amounts, VAT, due date and line items from it.
- **The program verifies the supplier.** It finds the company in ARES and checks in the VAT payer register that it is not an unreliable payer and that the account on the invoice is published. It also recalculates totals and VAT and flags duplicate documents.
- **You decide.** For a document with a warning you will see exactly what does not add up, and you decide yourself whether to pay, ask the supplier for a published account, or send the VAT to their tax office.
- **The data moves on.** The confirmed document is entered in your company records and in your accounting program, such as Pohoda, Money or Fakturoid.

But a supplier can also become unreliable between two invoices. This is where [Radar for monitoring business partners](https://otrock.cz/en/radar) helps. It keeps watch on the partners you name in the VAT payer register, in ARES and in the insolvency register. Urgent matters, for example when a partner becomes an unreliable VAT payer or changes its account, reach you straight away in Telegram. Other changes are in the weekly email summary, and matters with a deadline are recorded as a task.

Both helpers follow the same split: AI reads, the program calculates and checks against the registers, and a person decides on the payment.

## Summary: what to check before every payment

- Liability for a supplier's VAT applies to you if you are a VAT payer and buy for your business.
- The supplier is not listed in the VAT payer register as an unreliable VAT payer.
- The account on the invoice exactly matches one of the supplier's published bank accounts.
- The price matches the usual price, and you do not pay the same supplier more than CZK 270,000 in cash per day.
- You run the check both when the invoice arrives and right before payment, and you save the result.
- If something does not match, you request the published bank account, or you pay the VAT directly to the supplier's tax office under Section 109a.

This article describes the law as of October 2026. It is general information, not tax advice, and the final word for your company rests with your accountant or tax advisor.

Want a program to check the supplier on every invoice you receive? Book a [free consultation](https://otrock.cz/en/free-consultation?pomocnik=vytezovani) on invoice extraction. We will go through how documents reach you today and who approves them for payment, and I will show you how a supplier check would work in your case.

 OT**Ondřej Tóth**Web and app developer, Štramberk

I have been building websites and apps for Czech companies since 2014, and AI automation for clients since 2024. I handle the design, the build and the maintenance myself. In the consultation, you talk to me directly.

## Supplier checks on every invoice and in between them

Invoice extraction checks the supplier on every document, and Radar monitors partners between two invoices.

- [**Invoice and document extraction**AI reads the document, the program checks the supplier, account and totals, and you confirm.More about invoice extraction](https://otrock.cz/en/invoice-extraction)
- [**Radar**Watches your partners in the VAT payer register, ARES and the insolvency register.More about radar](https://otrock.cz/en/radar)

## Bring one invoice from a supplier

In the free consultation I will extract it in front of you. You will see what AI reads, how the program verifies the supplier and its account, and what is left for you to approve.

30 minutes free, over a video call. We get back to you within one day.

 [Free consultation](https://otrock.cz/en/free-consultation) [Call +420 774 862 198](tel:+420774862198)