How and when to check a marketplace seller's UK VAT number, what the HMRC check confirms, what it does not, and how to act on mismatches.
A VAT number on a seller's profile or invoice looks like a mark of a real, established business. Buyers often read it that way, especially business buyers who want to reclaim VAT. That is exactly why a fake or borrowed VAT number is worth checking for.
This post covers when to check a seller's VAT number, how to do it, what the result tells you and what to do when it does not match.
This is general information, not tax or legal advice. VAT rules for marketplaces and overseas sellers are complex. See GOV.UK guidance and take professional advice for your business.
There are three main reasons to care:
Buyer trust. Business buyers rely on VAT details on invoices. An invalid number causes them problems later, and those problems come back to you.
Consistency. A VAT number registered to a different business than the seller claims to be is a strong warning sign. It suggests a borrowed identity or a seller who is not who they say.
Your own obligations. In some situations, VAT rules place responsibilities on online marketplaces, particularly for overseas sellers. GOV.UK has guidance on VAT and overseas goods sold to customers in the UK, including how sales through online marketplaces are treated. Your tax adviser can tell you what applies to you.
A missing VAT number is not suspicious in itself. According to GOV.UK, a business must register for VAT if its taxable turnover for the last 12 months goes over £90,000, or is expected to go over that in the next 30 days. Below that, registration is voluntary.
Many smaller marketplace sellers, individuals and sole traders will never be VAT-registered. Do not make a VAT number mandatory for everyone. Ask for it from sellers who say they are VAT-registered, display VAT on listings, or issue invoices that charge VAT.
HMRC provides a public service to check a UK VAT number. It tells you whether a UK VAT registration number is valid, and shows the name and address of the business it is registered to.
If you are VAT-registered yourself, the same service can give you a reference showing when you checked a number. That is useful if anyone later asks what you did.
A simple process:
Valid, and the name matches. Good. Note any address differences; businesses often register VAT at an accountant's or head office address.
Valid, but registered to a different business. Treat as a serious mismatch. Ask the seller to explain. A trading name that differs from the legal name is common and explainable. A completely unrelated business is not.
Invalid. Could be a typo. Ask the seller to confirm the number. If it is still invalid, it should not appear on listings or invoices.
The service is unavailable. That is not a failure by the seller. Retry later, and keep the check pending rather than marking it failed.
For limited company sellers, the VAT check is most useful alongside a Companies House check. Matching the company name, number and address against the VAT registration gives a stronger picture than either alone.
TrustVerify's UK business check covers the Companies House side: company profile and status, officers, PSC count, insolvency flag and sanctions screening of the company and its officers. See the UK KYB guide. Our post on how to verify a UK company seller walks through the full flow. [Planned URL, live on publication.]
VAT registrations can be cancelled. Consider re-checking:
Making VAT mandatory for all sellers. It excludes legitimate small sellers and invites made-up numbers.
Checking format only. A number can look right and still be invalid or belong to someone else.
Ignoring the name. A valid number registered to another business is worse than no number.
Not recording the check. If you cannot show when and how you checked, the check is hard to rely on later.
Sellers based outside the UK raise different VAT questions. Depending on where goods are located and how they are sold, VAT may be handled differently, and the marketplace itself may have responsibilities. The GOV.UK guidance linked above is the place to start, and this is an area where professional tax advice is worth having before you design your onboarding rules.
For verification purposes, the practical point is simple: if an overseas seller quotes a UK VAT number, check it on the HMRC service just as you would for a UK seller. If they quote a VAT number from another country, the HMRC UK service will not cover it, and you will need the relevant national or regional checking service.
For each VAT check, keep the number checked, the date, the result, the registered name and address returned, and any reference the service provides. Note what you did about any mismatch. That record is what turns a check into evidence.
If you only remember a few points from this post, make them these:
None of these points requires a large team or a long project. Most can be put in place in a few weeks, and each one makes the next decision easier to explain.
Pair VAT checks with a full UK registry check on company sellers. Read about TrustVerify UK registry checks.
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