26 CFR § 1.6414-1 - Credit or refund of tax withheld on nonresident aliens and foreign corporations.
(1) Tax required to be withheld under chapter 3 of the Code, or
(b) Claim for credit on Form 1042. The withholding agent may claim credit of an overpayment described in paragraph (a) of this section for any calendar year by showing the amount of overpayment on the return on Form 1042 for such calendar year, which shall constitute a claim for credit under this paragraph. The claim for credit shall be evidenced by a statement on the return setting forth the amount determined as an overpayment and showing such other information as may be required by the instructions relating to the return. The amount claimed as a credit may be applied, to the extent it has not been applied under § 1.1461-2(b), by the withholding agent to reduce the amount of a payment or deposit of tax required by § 1.1461-1 or § 1.6302-2(a) for any payment period occurring in the calendar year following the calendar year of overwithholding. The amount so claimed as a credit shall also be entered on the annual return on Form 1042 for the calendar year following the calendar year of overwithholding and shall be applied as a payment on account of the tax shown on such form. If the withholding agent files a claim for credit or refund of the overpayment on Form 843 in accordance with § 301.6402-2 of this chapter (Procedure and Administration Regulations), or a claim for refund of the overpayment on Form 1042 in accordance with § 301.6402-3 of such chapter, he may not claim credit for the overpayment under this paragraph.
(c) Overpayment of amounts actually withheld. No credit or refund to the withholding agent shall be allowed for the amount of any overpayment of tax which, after taking into account paragraph (b) of § 1.1464-1, the withholding agent has actually withheld from an item of income under chapter 3 of the Code.