Reliable identifiers as a by-product of entity registration
Jurisdictions across the world allow the formation and legal recognition of companies and other corporate vehicles. The administration of these registration processes and the regulation of company activities by state authorities has required unambiguous identification of entities by those authorities. In many jurisdictions, this has led to the issuing of a reference code or number to an entity at the point of legal registration.
Within the scope of the issuing authority, this has acted as a reliable identifier: being unique, persistent and (amongst relevant state actors) resolvable. The CAC issuing CNC Engineering Company the reference number “RC-671630” is an instance of this.
Being so closely related to the legal incorporation of a company or other corporate vehicle within a jurisdiction, such identifiers are recognised as authoritative. If an entity declares that it has such an identifier, it is declaring that it is legally recognised by the given jurisdiction. The identifier can therefore prove valuable for uses beyond its initial administrative purpose. That is, as long as the issuing authority (company registrar, tax and revenue ministry or other regulator) can guarantee that the identifiers they issue and maintain are unique, persistent and (for all interested parties) resolvable. In that case, actors outside government can rely on the identifiers for general business and transparency purposes.
Indonesia and Norway are examples of EITI countries where such an approach has been taken when it comes to connecting company registers with licence registers. Norway uses reliable company identifiers from its Brønnøysundregistrene company register alongside identifiers issued by the Norwegian Petroleum Directorate on its public licence register.  Indonesia simplified its licensing process in 2018 by adding a single sign-on submission where companies have to register. As part of this new Government Regulation 24, Indonesia unified the company ID numbers through the “Business Identification Number”. 
However, it must be clear to those who come across an entity identifier which registration authority has issued it, and how they can check whether it is a valid identifier. The uniqueness of an identifier can only be guaranteed within a given scope. The identifier “RC-671630” may have been issued to CNC Engineering Company, but an identical identifier may have been given to a registered charity in South Africa.
In order for “RC-671630” to be useful, it has to be clear that it was issued in Nigeria. Even then, there are multiple issuing authorities in Nigeria, and it may be the case that a single authority will register different kinds of entities and manage multiple identifier schemes (for example, entities formed domestically as well as foreign-registered entities). A company identifier like “RC-671630” is only useful when it is clear as to which identifier scheme it comes from.
As with company names, the names of issuing authorities or identifier schemes can prove challenging to resolve. For this reason, projects such as org-id.guide  and the Authoritative Legal Entity Identifier (ALEI)  issue prefixes to identify company registers and identifier schemes. So, CNC Engineering Company has a globally unique identifier of “NG.CR:671630” under the ALEI, or “NG-CAC-RC-671630” under org-id.guide.
Once it is clear which register has issued the entity identifier, it will be necessary to check that it is valid within that register. In the digital age, this can be facilitated by register websites providing publicly searchable databases of companies and APIs to automatically check and verify data. Where APIs are developed, they should be well documented and maintained. One way of ensuring that users of identifiers know how to validate them is to provide up-to-date information about identifier schemes to org-id.guide.
By providing this kind of access, company registration authorities can comply with the FATF guidance that: “[basic information on companies] held by the company registry should be made publicly available”. 
Authorities which legally incorporate and register entities and provide them with a unique and persistent identifier should provide mechanisms to support the validating of entity identifiers, such as web search facilities and documented APIs.
 Norwegian Petroleum Directorate (updated 2023), “Aker BP ASA”, FactPages. Retrieved from: https://factpages.npd.no/en/company/pageview/all/28544099.
 Global Business Guide Indonesia (2018), “Indonesia Looks to Simplify Business Licensing With OSS System”. Retrieved from: https://www.gbgindonesia.com/en/main/legal_updates/indonesia_looks_to_simplify_business_licensing_with_oss_system.php.
 See: org-id.guide (updated 2023), Home page. Retrieved from: http://org-id.guide.
 See: ALEI (updated 2023), Home page. Retrieved from: https://ealei.org.
 See: FATF (2023), Beneficial Ownership of Legal Persons. Retrieved from: https://www.fatf-gafi.org/content/dam/fatf-gafi/guidance/Guidance-Beneficial-Ownership-Legal-Persons.pdf.coredownload.pdf.