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Explainer · KYB

What is KYB?

KYB (Know Your Business) is the process of verifying that a company is real, registered and not controlled by sanctioned parties before you do business with it. It is KYC for companies.

Below: how KYB differs from KYC, the 5 verification steps and what it costs to implement.

Updated 6 November 2026

The short answer

KYB ("Know Your Business") is the regulated process of verifying a corporate counterparty before transacting with it. It is to companies what KYC is to individuals — and it always includes KYC of the company's officers and beneficial owners, plus entity-specific checks the personal-side process doesn't cover.

To run these checks from code, see the KYB API: one REST call per check, with coverage by country. Terms such as UBO, CDD and EDD are defined in the glossary.

In practice, KYB means proving four things:

  1. The company legally exists — confirmed via the official registry (BORME for Spain, BODACC for France, Companies House for the UK, CRO for Ireland, KRS for Poland, Brønnøysundregistrene for Norway)
  2. You know who controls it — beneficial ownership, current officers, voting rights
  3. None of those parties are sanctioned — screened against EU consolidated, UN, OFAC, UK, Australia (DFAT), FR gels, plus the US Consolidated Screening List
  4. There's no obvious adverse signal — adverse media, ongoing litigation, recent insolvency proceedings

KYB vs KYC

KYC ("Know Your Customer") verifies an individual: name, date of birth, address, government-issued ID. KYB verifies a corporate entity. Where KYB intersects with KYC is in the requirement to verify the people behind the company — beneficial owners (usually defined as anyone owning ≥25%) and senior managing officials.

KYCKYB
Who is checkedAn individualA legal entity (company, partnership, association)
Typical evidenceGovernment ID, date of birth, addressRegistration number, legal name, legal form, registered address
Where the data comes fromThe person and an ID-verification providerThe official company register of the country
Beneficial ownersNot applicableIdentified and checked, usually anyone owning 25% or more
Sanctions screeningThe personThe company, then its owners and officers
After onboardingPeriodic refresh of the personMonitoring of status, dissolution, insolvency and sanctions changes

Prometiam serves the registry and sanctions side of this table; beneficial owners only where a register publishes them (UK PSC), and no identity verification of people.

What does KYB stand for?

KYB stands for Know Your Business. It is the check that a company is real, legally registered and not controlled by sanctioned or high-risk parties, done before you onboard it or trade with it. The term mirrors KYC, Know Your Customer, which does the same for individuals.

What is the difference between KYC and KYB?

KYC verifies an individual from an ID document; KYB verifies a company from the official registry: that it exists, its legal form and address, who runs it and whether they appear on sanctions lists. KYB always pulls in KYC of the owners and officers behind the company, so the two run together.

So a complete KYB check on a Spanish SL with 3 shareholders and 2 directors typically requires:

  • 1 registry check on the legal entity
  • 1 sanctions check on the legal entity
  • 5 KYC checks (3 owners + 2 directors) including ID-document verification
  • 5 sanctions checks on the natural persons
  • Adverse-media screen on the legal entity and the 5 natural persons

Prometiam covers the registry and sanctions legs (the company-side and natural-persons-name-screening parts). For ID-document verification of the natural persons, you'd pair Prometiam with a KYC vendor like Sumsub, Veriff, or Onfido.

Where KYB is legally required

  • European Union: 5th AML Directive (Directive (EU) 2018/843) and 6th AMLD (2018/1673). Applies to all "obliged entities" — banks, payment institutions, EMIs, crypto-asset service providers, accountants, lawyers, real-estate agents.
  • United Kingdom: Money Laundering Regulations 2017 (as amended). Same scope.
  • United States: Customer Due Diligence rule (31 CFR 1010.230) for banks, plus FinCEN's 2024 Beneficial Ownership Information rule for most entities.
  • Spain (national transposition): Ley 10/2010 de prevención del blanqueo de capitales y de la financiación del terrorismo, plus its 2010 royal decree.
  • France: Code monétaire et financier, articles L561-1 et suivants.

The penalties for failure are material — multi-million-euro administrative fines under EU AMLD, plus reputational damage. KYB is not optional for regulated firms.

The 5 standard verification steps

Most production KYB pipelines run in this order:

1. Identifier check

Format and checksum validation of the corporate identifier (Spanish NIF, French SIREN, UK Companies House number). Done locally in milliseconds — see our Python tutorial for NIF.

2. Registry resolution

Confirm the company is registered, currently active, and pull metadata (name, legal form, address, capital, founding date, current officers). One API call per country: GET /companies/search?nif=…&country=ES then GET /companies/{id}.

3. Beneficial-ownership identification

For UK companies, the PSC register gives you direct beneficial-ownership data. For Spanish and French companies, you'd query the national UBO register (Registro de Titularidad Real / Registre des Bénéficiaires Effectifs) — neither is currently exposed by Prometiam, so most teams collect a self-declaration during onboarding and verify it against documents.

4. Sanctions + PEP screening

Screen the legal entity name and every officer/owner name against EU consolidated, UN, OFAC, UK, Australia (DFAT), FR gels, plus the US Consolidated Screening List. Prometiam covers all seven sources in /sanctions/screen (beta). PEP and adverse-media coverage typically come from a separate vendor (ComplyAdvantage, Refinitiv World-Check, Dow Jones).

5. Adverse-media + risk scoring

Open-web search for negative news, ongoing litigation, regulatory enforcement. Combined with the registry data and sanctions hits, an internal risk score determines whether onboarding proceeds straight through, requires manual review, or is rejected.

Common implementation patterns

Synchronous KYB: the entire flow runs while the user waits at the signup form. Works only if you can complete in <3 seconds — feasible for the registry + sanctions legs alone (typically ~500ms each), not for full ID-document verification.

Asynchronous KYB with provisional account: create a limited-functionality account immediately, run the full KYB pipeline in the background, lift restrictions when verified. This is the modern fintech default.

Batch KYB for migrating customers: when onboarding an existing book of customers to a new platform, run the entire KYB pipeline overnight against your customer list in one batch. Prometiam's /companies/search with a list of NIFs is well-suited; consult our KYB onboarding use-case page for the pattern.

Continuous KYB: re-run lighter KYB checks periodically (every quarter, every transaction, or on event triggers) to catch material changes. The counterparty-monitoring pattern is the recommended way to do this on multi-country companies — daily-fresh registry events and re-screen on any change.

What KYB costs

Full-service KYB and identity platforms (Trulioo, Sumsub, Veriff, Persona, Alloy) generally price per check, with the rate depending on depth — a simple legal-entity lookup costs less than a full check that adds UBO collection and document verification, and high-risk jurisdictions cost more again. None of them publish a public rate card, so the actual number comes from a sales conversation and varies with your volume and risk profile. We deliberately don't quote figures for them here: any range we printed would be hearsay.

API-led approaches separate the data layer from the workflow layer. The data layer:

  • Creditsafe / Iberinform / Bureau van Dijk: typically €3K–€15K/year for SMB volume
  • Pappers (FR-only): from €19/mo to €79+/mo for API access
  • Companies House Public API (UK-only): free with rate-limit ceiling
  • Prometiam (ES + FR + GB + IE + PL + NO + FI + SE + BE + HR + DK + EE + SK + CH + LV + CY + RO + LT + CA + AU + JP + IL + SG + CO + TW + BR + CZ): €9.99/mo for 1,000 credits/month, €29.99/mo for 10,000 credits/month with sanctions screening (beta)

For multi-country scope at SMB volume, the API-led approach with Prometiam is typically 50–95% cheaper than vendor platforms — at the cost of building the workflow layer yourself.

Common misconceptions

  • "KYB is one-time." No — regulators expect periodic re-verification, especially after material events (capital changes, ownership transfers, address moves).
  • "Sanctions screening is enough." No — sanctions hits are the high-confidence flag, but adverse-media and PEP screening catch a different set of risks.
  • "Free Companies House is sufficient for UK." For UK-only, low-volume use, yes. For multi-country or high-volume, no — you'll hit the 600/5min rate limit and you still need sanctions.
  • "You can outsource the legal accountability." No — under EU AMLD the obliged entity remains responsible for its own KYB even when using a vendor.

FAQ

What does KYB mean, and what is the KYB full form?
KYB stands for Know Your Business. The term means checking that a company is real, legally registered and not controlled by sanctioned or high-risk parties before you transact with it. It is the company-side counterpart of KYC (Know Your Customer), which checks individuals.

What is KYB?
Verifying a corporate counterparty before transacting. Required by EU AMLD5/6 for obliged entities.

How is KYB different from KYC?
KYC verifies people; KYB verifies companies (and includes KYC of their officers and owners).

Is KYB legally required?
Yes for regulated entities in the EU, UK, US, and most major jurisdictions.

How much does KYB cost?
Full-service platforms price per check and don’t publish rate cards, so the number comes from a sales call. Prometiam is published and flat: €9.99–€29.99/month, with 500 free credits over 14 days.

How long does a KYB check take?
API-driven verification under a second; full process 24–72 hours including UBO collection.

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