A practical order of checks for verifying a UK limited company seller on a marketplace: Companies House, the people behind it, VAT and FCA status.
When a seller signs up as a limited company, most marketplaces ask for a company number and stop there. If Companies House says the company is active, the seller is approved. It feels like a check. It is really just confirmation that a company with that number exists.
This post sets out a practical order of checks for UK company sellers, what each one tells you, and where the gaps are.
Start with the company record itself. Ask for the company number, not just the name. Names are easy to get slightly wrong, and there are many companies with similar names.
From the register you want:
Look at the details together. A company incorporated last week, with SIC codes for property management, selling high-value electronics on your platform, is worth a second look even if everything is technically in order.
TrustVerify's KYB check does this against the live Companies House register through POST /api/v1/kyb/verify. A company number resolves directly. A company name has to clear a similarity threshold against the registered name; if it does not, the API returns a ranked "did you mean" list instead of guessing. The response includes the company profile, officers, PSC count, an insolvency flag and a registry risk score. The UK KYB guide covers the fields.
Results come back as one of four statuses:
That last one matters. "Unverified" is never a pass. Only UK companies (jurisdiction GB) are supported today; a company registered elsewhere comes back unverified, and your process should send it to a person.
A company record tells you who is officially in charge. It does not tell you that the person filling in your signup form is one of them.
This is the gap most often missed. Company numbers are public. Anyone can type a real one in. So once the company is matched:
The register itself is getting stronger here. Companies House began mandatory identity verification for directors and PSCs on 18 November 2025, with new directors needing to verify to be appointed and existing ones confirming within 12 months (Companies House). That raises the bar for who appears on the register. It still does not tell you who is sitting at the keyboard on your site.
Our post on directors, PSCs and UBOs goes deeper on the ownership side. [Planned URL, live on publication.]
Screen the company and its officers against sanctions lists before you approve. In TrustVerify's KYB check, registry-verified companies and their active officers are screened through OpenSanctions with material-hit scoring. Weak or wrong-entity-type candidates are discarded and counted, so a common name does not automatically turn into a hit. The result sits in the aml part of the response as clear, review, hit or not_screened.
"Not screened" is not the same as clear. If screening did not run, the check goes to review rather than passing. Our post on sanctions screening for business sellers covers this in more depth.
If the seller quotes a VAT number, on their listings or their invoices, check that it is valid and belongs to this company. HMRC's Check a UK VAT number service confirms 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 service can also give you proof of when you checked.
TrustVerify does not check VAT numbers; this is a check your team runs on the public HMRC service. What you are looking for is consistency. A valid VAT number registered to a different business is a stronger warning sign than no VAT number at all.
Most marketplace sellers do not need FCA authorisation. But if a seller says they hold FCA authorisation, for example because they offer credit, insurance or financial products, check the claim on the public Financial Services Register. Match the firm name, the reference number and what it is permitted to do.
Put the results together into a decision your team can explain later:
Keep a record of what you checked and when. A KYB check can include a PDF report (RPT-002) through the generateReport option, which is useful when a bank, payment partner or auditor asks how a seller was approved. See the reports guide.
Accepting the name without the number. Ask for the number and compare names.
Treating "active" as approval. Active only means the company has not been dissolved or struck off.
Skipping the applicant. The company may be real. The person might not be connected to it.
Re-checking never. Company status, officers and sanctions lists change. Look at ongoing monitoring for sellers you rely on.
Many marketplaces have both company sellers and individuals or sole traders. For individuals, identity checks carry most of the weight. Our posts on passport MRZ and selfie checks and integrating KYC via API cover that side.
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.
If your seller onboarding stops at "company exists", see what a full UK registry check returns. Read about TrustVerify UK registry checks.
KYC, KYB, AML screening and fraud prevention in one place, with published pricing.
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