Maintained by the Global Legal Entity Identifier Foundation, the Index contains current and historical Legal Entity Identifier records.
"The Legal Entity Identifier (LEI) is a 20-character, alpha-numeric code based on the ISO 17442 standard developed by the International Organization for Standardization (ISO). It connects to key reference information that enables clear and unique identification of legal entities participating in financial transactions. Each LEI contains information about an entity’s ownership structure and thus answers the questions of 'who is who’ and ‘who owns whom’. Simply put, the publicly available LEI data pool can be regarded as a global directory, which greatly enhances transparency in the global marketplace." 
LEIs are granted not by the Foundation but by designated issuers. Any legal entity making financial transactions can apply for an LEI, including non-registered entities such as trusts and government bodies. In general, natural persons are not eligible for LEIs .
: From https://www.gleif.org/en/about-lei/introducing-the-legal-entity-identifier-lei
: See this for exceptions: https://www.leiroc.org/publications/gls/lou_20150930-1.pdf