26 C.F.R. § 301.6414-1

Income tax withheld.

        (a) For rules relating to the refund or credit of income tax withheld under chapter 3 of the Code on nonresident aliens and foreign corporations and tax-free covenant bonds, see § 1.6414–1 of this chapter (Income Tax Regulations).

        (b) For rules relating to the refund or credit of income tax withheld under chapter 24 of the Code from wages, see § 31.6414–1 of this chapter (Employment Tax Regulations).

Official source