(a) Overpayment of wagering tax; in general. If a person overpays the tax imposed under section 4401, he may either file a claim for refund on Form 843 or take credit for such overpayment against the tax due on a subsequent monthly return. A complete statement of the facts involving the overpayment shall be attached either to the claim or to the return on which the credit is claimed. Every claim for refund shall be supported by evidence showing the name and address of the taxpayer, the date of payment of the tax, and the amount of such tax. A credit taken on a return shall be supported by evidence of the same character.

(b) Statement supporting credit or refund. No credit or refund shall be allowed whether in pursuance of a court decision or otherwise unless the taxpayer files a statement explaining satisfactorily the reason for claiming the credit or refund and establishing (1) that he has not collected (whether as a separate charge or otherwise) the amount of the tax from the person who placed the wager on which the tax was imposed, or (2) that he has either repaid the amount of the tax to the person who placed the wager or has secured the written consent of such person to the allowance of the credit or refund. In the latter case, the written consent of the person who placed the wager shall accompany the statement filed with the credit or refund claim. The statement supporting the credit or refund claim shall also show whether any previous claim for credit or refund covering the amount involved, or any part thereof, has been filed. If the overpayment of tax relates to a laid-off wager accepted by the taxpayer, no credit or refund shall be allowed or made unless the taxpayer complies with the provisions of the first sentence of this paragraph, not only as to the person who placed the laid-off wager, but also with respect to the person who placed the original wager.

(c) Limitation on credit or refund. No claim for credit or refund of a tax shall be allowed unless presented within the period of limitations prescribed in section 6511. (For regulations under section 6511, see the Regulations on Procedure and Administration (part 301 of this chapter).)