26 C.F.R. § 1.996-6
In the case of a shareholder who is a nonresident alien individual or a foreign corporation, trust, or estate, amounts taxable as dividends by reason of the application of § 1.995-4 (relating to gain on disposition of stock in a DISC), amounts treated under § 1.996-1 as distributed out of accumulated DISC income, and amounts deemed distributed under § 1.995-2(a) (1) through (4) shall be treated as gains and distributions which are effectively connected with the conduct of a trade or business conducted through a permanent establishment of such shareholder within the United States, and shall be subject to tax in accordance with the provisions of section 871(b) and the regulations thereunder in the case of nonresident alien individuals, trusts, or estates, or section 882 and the regulations thereunder in the case of foreign corporations. In no case, however shall other income of such shareholder be taxable as effectively connected with the conduct of a trade or business through a permanent establishment in the United States solely because of the application of this section.
26 C.F.R. §1.996-6