What Is an LEI? ISO 17442 Structure and Check Digits
A Legal Entity Identifier (LEI) is a 20-character code that identifies a legal entity worldwide. ISO 17442 defines it, GLEIF-accredited Local Operating Units issue it, and its last two characters are MOD-97-10 check digits.
Updated 2026-09-30 · 5 min read
What an LEI is
A Legal Entity Identifier identifies a legal entity — a company, fund, or trust — that takes part in a financial transaction. It is not an account number and it is not a tax identifier.
The LEI is global and permanent: the same 20-character code is used everywhere the entity trades, which is why regulators mandate it in reporting.
How the 20 characters are structured
An LEI has four parts, in order: a four-character prefix identifying the issuing unit, two reserved digits that are normally 00, twelve characters specific to the entity, and two check digits.
Because the issuing prefix is included, an LEI is not anonymous; it points back to the Local Operating Unit that issued and maintains the record.
| Part | Characters | Meaning |
|---|---|---|
| Issuer prefix | 4 | GLEIF-accredited LOU that issued the LEI |
| Reserved | 2 | Reserved, normally 00 |
| Entity-specific | 12 | Identifier assigned to the entity |
| Check digits | 2 | ISO 7064 MOD-97-10 checksum |
The check digits
The final two characters are a MOD-97-10 checksum over the preceding eighteen characters. Letters are converted to numbers using A = 10 through Z = 35, exactly as in an IBAN.
For example, the reference LEI 5493006MHB84DD0ZWV18 reduces to 5493006221711841313035323118, which is congruent to 1 modulo 97.
Level 1 and Level 2 data
GLEIF publishes two data layers. Level 1 is the “who is who”: the legal name, address, registration, and status of the entity. Level 2 is the “who owns whom”: the parent and child relationships between entities.
A BIC-to-LEI mapping lets a payment system resolve a bank’s BIC to the LEI of the legal entity behind it, which is why the two are often checked together.
Where LEIs are required
Financial regulators require an LEI for entities that report under frameworks including MiFID II and EMIR in the EU and the Dodd-Frank Act in the United States.
Because the requirement is legal rather than technical, an invalid LEI usually blocks a report outright rather than producing a warning.
Try it on real data
Frequently Asked Questions
An LEI is exactly 20 alphanumeric characters: a four-character issuing prefix, two reserved digits, twelve entity-specific characters, and two check digits.
No. A BIC identifies a bank, a VAT number identifies a tax registration, and an LEI identifies a legal entity for financial reporting. A BIC-to-LEI mapping links the bank to its legal entity.
The last two characters are an ISO 7064 MOD-97-10 checksum. Convert letters to numbers (A=10 to Z=35) across the preceding eighteen characters and reduce modulo 97.