LEI
LEIs are twenty-character ISO 17442 entity codes mandated for EMIR and MiFID reporting, issued through the GLEIF federation.
The Legal Entity Identifier answers a different question from everything else in this track: not which instrument, but which legal person. ISO 17442 defines a twenty-character code, eighteen alphanumeric characters plus two check digits, uniquely identifying an entity that enters into financial transactions. Regulation made it unavoidable: EMIR and MiFID reporting require an LEI for every counterparty, so banks, funds, and corporates trading in Europe must hold one. The Global Legal Entity Identifier Foundation accredits Local Operating Units that issue and annually renew LEIs, and GLEIF publishes free relationship data plus a public search API, making entity resolution far easier than chasing vendor-by-vendor lookups.