Any government-provided number that can be used in the US as a
unique identifier when interacting with the IRS is a TIN, though none of them are referred to exclusively as a Taxpayer Identification Number. A TIN may be: • a
Social Security number (SSN) • an
Individual Taxpayer Identification Number (ITIN) • an
Employer Identification Number (EIN), also known as a FEIN (Federal Employer Identification Number) • an Adoption Taxpayer Identification Number (ATIN), used as a temporary number for a child for whom the
adopting parents cannot obtain an SSN • a
Preparer Tax Identification Number (PTIN), used by paid
preparers of
US tax returns SSNs SSNs are used by people who have or had the right to work in the United States.
ITINs ITINs are used by
aliens who may or may not have the right to work in the US, such as aliens on temporary visas and non-resident aliens with US income.
EINs EINs are used by employers,
sole proprietors,
corporations,
LLCs,
partnerships,
non-profit associations,
trusts, estates of decedents, government agencies, certain individuals, and other business entities. ==Relevant Internal Revenue Code sections==