What is an LEI?

Core Definition: A Legal Entity Identifier (LEI) is a 20-character code defined by the ISO 17442 standard. It identifies legal entities that take part in financial transactions and reporting.

Definition and Purpose

The LEI gives legal entities a standard identifier that can be used across markets, reporting systems, and jurisdictions. Each code links to reference data such as the entity's legal name, registered address, and registration details.

Regulators pushed for the LEI system after the 2008 financial crisis, when it was often difficult to tell which entities sat on either side of a trade. The system is backed by the G20 and overseen by the Regulatory Oversight Committee (ROC — ROC (Regulatory Oversight Committee) — an international group of public authorities providing oversight of the LEI system.ROC: ROC (Regulatory Oversight Committee) — an international group of public authorities providing oversight of the LEI system.) so firms and regulators can match counterparties more reliably across different jurisdictions — The country or legal area whose laws and regulations apply to an entity or activity.jurisdiction: The country or legal area whose laws and regulations apply to an entity or activity..

LEI reference data: Level 1 and Level 2

An LEI is not just a code. It links to public reference data that helps users identify an entity and, where available, its ownership relationships. This is commonly described as:

• Level 1 data (Who is Who): core identity data such as legal name, registered address, and jurisdiction.
• Level 2 data (Who owns Whom): relationship data describing direct and ultimate parent entities where applicable.

Entities Typically Requiring an LEI

An LEI is usually required when an entity trades certain instruments, files reports, or interacts with a regime that expects standardized entity data:

Structure of the LEI Code

The 20-character LEI code follows a defined structure specified by ISO 17442:

The Global LEI System (GLEIS — GLEIS (Global LEI System) — the global framework of rules and institutions that supports issuing and publishing LEIs.GLEIS: GLEIS (Global LEI System) — the global framework of rules and institutions that supports issuing and publishing LEIs.)

The Global LEI System is the framework ensuring the operational integrity and accessibility of LEIs worldwide. Key components include:

• Global Legal Entity Identifier Foundation (GLEIF — GLEIF — the organization that coordinates the global LEI system and maintains data quality in the Global LEI Index.GLEIF: GLEIF — the organization that coordinates the global LEI system and maintains data quality in the Global LEI Index.): A non-profit organization responsible for coordinating the system, ensuring data quality, and managing the network of LEI issuers.
• Regulatory Oversight Committee (ROC — ROC (Regulatory Oversight Committee) — an international group of public authorities providing oversight of the LEI system.ROC: ROC (Regulatory Oversight Committee) — an international group of public authorities providing oversight of the LEI system.): A group of public authorities from around the globe providing governance and oversight of the GLEIS — GLEIS (Global LEI System) — the global framework of rules and institutions that supports issuing and publishing LEIs.GLEIS: GLEIS (Global LEI System) — the global framework of rules and institutions that supports issuing and publishing LEIs..
• Local Operating Units (LOUs — LOU (Local Operating Unit) — an accredited organization that issues/renews LEIs and validates entity data.LOU: LOU (Local Operating Unit) — an accredited organization that issues/renews LEIs and validates entity data.): Organizations accredited by GLEIF — GLEIF — the organization that coordinates the global LEI system and maintains data quality in the Global LEI Index.GLEIF: GLEIF — the organization that coordinates the global LEI system and maintains data quality in the Global LEI Index. to issue LEIs to legal entities, performing validation and ensuring data accuracy according to established protocols.
• Registration Agents — A service provider that helps entities register or renew an LEI (typically in cooperation with an LOU).Registration Agent: A service provider that helps entities register or renew an LEI (typically in cooperation with an LOU).: Organizations assisting entities in accessing LEI issuing services provided by LOUs — LOU (Local Operating Unit) — an accredited organization that issues/renews LEIs and validates entity data.LOU: LOU (Local Operating Unit) — an accredited organization that issues/renews LEIs and validates entity data..