26 CFR § 31.3121(h)-1 - American employer.

(a) The term “American employer” means an employer which is (1) the United States or any instrumentality thereof, (2) an individual who is a resident of the United States, (3) a partnership, if two-thirds or more of the partners are residents of the United States, (4) a trust, if all of the trustees are residents of the United States, or (5) a corporation organized under the laws of the United States or of any State. For provisions relating to the terms “State” and “United States”, see § 31.3121(e)–1.

(b) For provisions relating to services performed outside the United States by a citizen of the United States as an employee for an American employer, see paragraph (c)(3) of § 31.3121(b)–3 and paragraph (e) of § 31.3121(b)(4)–1.

[T.D. 6516, 25 FR 13032, Dec. 20, 1960, as amended by T.D. 6744, 29 FR 8315, July 2, 1964]