A TIN may be assigned by the Social Security Administration (SSA) or by the Internal Revenue Service (IRS).
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.
Section 6109(a) of the Internal Revenue Code provides (in part) that "When required by regulations prescribed by the Secretary [of the Treasury or his delegate] [ .
Any person required under the authority of this title [i.e., under the Internal Revenue Code] to make a return, statement, or other document shall include in such return, statement or other document such identifying number as may be prescribed for securing proper identification of such person.
"[3] Internal Revenue Code section 6109(d) provides: "The social security account number issued to an individual for purposes of section 205(c)(2)(A) of the Social Security Act [codified as 42 U.S.C.