What it is
The Legal Entity Identifier (LEI) is a 20-character, alphanumeric code that uniquely and unambiguously identifies a legally distinct entity that participates in financial and commercial transactions. It is defined by ISO 17442 and managed under the Global LEI System, which was created after the 2008 financial crisis on the initiative of the G20 and the Financial Stability Board so that counterparties could be identified consistently across borders and registries.
The code has a fixed structure:
For example, 5493001KJTIIGC8Y1R12 is a well-formed LEI. Each LEI is backed by public reference data — the entity's legal name, registered address, and (where applicable) its direct and ultimate parent — published openly by GLEIF (the Global Legal Entity Identifier Foundation), the supranational not-for-profit that oversees the system. LEIs must be renewed annually for the reference data to stay "current". ISO 17442-3:2024 adds the verifiable LEI (vLEI), a cryptographically verifiable credential form of the identifier.
Why it matters for e-invoicing
In an EU e-invoice the seller and buyer must be identified, and on a network like Peppol they must also be addressable — routed to the correct receiving access point. Both of these rely on coded identifier schemes drawn from the ISO/IEC 6523 ICD registry. The LEI is one of those schemes: in the Peppol Electronic Address Scheme (EAS) and participant-identifier code lists, scheme code 0199 denotes "Legal Entity Identifier (LEI)". That means a participant can legitimately be registered and addressed by their LEI rather than by a national company number, a VAT number, or a GLN.
In practice national identifiers (VAT numbers, CVR, SIRET, KVK, the Italian Codice Destinatario) and the GLN dominate Peppol routing today, and the LEI is comparatively rare as a routing address. But it is fully valid, and it is increasingly relevant where a single global identifier is preferred — multinational groups, financial-sector counterparties already holding LEIs for regulatory reporting, and emerging digital-trust use cases built on vLEIs. ViDA and the broader push toward verifiable organisational identity make the LEI worth understanding even if you rarely route on it.
How ERP vendors encounter it
You will meet the LEI in three places:
1. As an electronic address (BT-34 seller / BT-49 buyer). Populate the endpoint with schemeID="0199" and the 20-character LEI as the value.
2. As a party legal-registration identifier (BT-30 seller / BT-47 buyer). Some profiles allow the LEI as the company-registration scheme.
3. In validation. A robust pipeline should range-check the format (20 chars, allowed character set) and ideally verify the ISO 7064 check digits before trusting an inbound LEI. Unlike a VAT number, an LEI's existence can be confirmed against GLEIF's public lookup API.
Relation to EN 16931
EN 16931 does not mandate any one identifier scheme; it requires that identified parties use a scheme from the agreed code lists, and BT-34/BT-49 (electronic address) carry both a value and a scheme identifier. The LEI is simply one permitted scheme value (0199). A vendor's job is therefore not to prefer the LEI but to accept it: parse it, validate its check digits, and route on it when a counterparty has registered their LEI as their Peppol participant ID. Treating 0199 as "unknown scheme" is a common, avoidable source of rejected or misrouted invoices.