As defined in ISO 17442, the standard underlying the Legal Entity Identifier (LEI), the term ‘legal entity’ includes, but is not limited to, unique parties that are legally or financially responsible for the performance of financial transactions or have the legal right in their jurisdiction to enter independently into legal contracts, regardless of whether they are incorporated or constituted in some other way (e.g. trust, partnership, contractual). It excludes natural persons, but includes governmental organizations and supranationals.
It is important to distinguish between being eligible for an LEI and being required to have one. As defined in ISO standard 17442, any legal entity that enters into a financial transaction is eligible for an LEI. Any legal requirement to have an LEI will come from national financial regulators.
A list of regulatory initiatives relevant to LEI adoption is available here.