In the case of any nonresident alien individual or foreign corporation, there is hereby imposed for each taxable year a tax equal to 4 percent of such individual’s or corporation’s United States source gross transportation income for such taxable year.

For purposes of this chapter, United States source gross transportation income of any taxpayer shall not be treated as effectively connected with the conduct of a trade or business in the United States unless—

(1) In general Except as provided in paragraphs (2) and (3), the term “United States source gross transportation income” means any gross income which is transportation income (as defined in section 863(c)(3)) to the extent such income is treated as from sources in the United States under section 863(c)(2). To the extent provided in regulations, such term does not include any income of a kind to which an exemption under paragraph (1) or (2) of section 883(a) would not apply.

(2) Exception for certain income effectively connected with business in the United States The term “United States source gross transportation income” shall not include any income taxable under section 871(b) or 882.

(3) Exception for certain income taxable in possessions The term “United States source gross transportation income” does not include any income taxable in a possession of the United States under the provisions of this title as made applicable in such possession.

For purposes of this chapter, United States source gross transportation income of any taxpayer shall not be treated as effectively connected with the conduct of a trade or business in the United States unless—

(A) the taxpayer has a fixed place of business in the United States involved in the earning of United States source gross transportation income, and

(B) substantially all of the United States source gross transportation income (determined without regard to paragraph (2)) of the taxpayer is attributable to regularly scheduled transportation (or, in the case of income from the leasing of a vessel or aircraft, is attributable to a fixed place of business in the United States).

Any income taxable under this section shall not be taxable under section 871, 881, or 882.

(Added Pub. L. 99–514, title XII, § 1212(b)(1), Oct. 22, 1986, 100 Stat. 2537; amended Pub. L. 100–647, title I, § 1012(e)(6), Nov. 10, 1988, 102 Stat. 3500; Pub. L. 101–239, title VII, § 7811(i)(8)(A), (B), (9), Dec. 19, 1989, 103 Stat. 2410, 2411.)