The Legal Entity Identifier (LEI) is a unique global identifier for legal entities participating in financial transactions. Also known as an LEI code or LEI number, its purpose is to help identify legal entities on a globally accessible database. Legal entities are organizations such as companies or government entities that participate in financial transactions. An individual person may not obtain an LEI. The identifier is used in regulatory reporting to financial regulators and all financial companies and funds are required to have an LEI.

The identifier is formatted as a 20-character, alpha-numeric code based on the ISO 17442 standard developed by the International Organization for Standardization (ISO). It connects to key information that enables a clear and unique identification of legal entities participating in financial transactions. Each LEI database entry contains information about an entity’s ownership and thus answers the questions of ‘who is who and ‘who owns whom. Therefore the publicly available LEI data pool can be regarded as a global directory of non-individual participants in the financial market.

There are a number of LEI issuers around the world that issue and maintain the identifiers and act as primary interfaces to the global directory, these are typically financial exchanges or financial data vendors. These are accredited by the Global Legal Entity Identifier Foundation (GLEIF) to issue LEIs.