(a) Finality of refund proceeding. For purposes of sections 4941, 4942, 4943, 4944, 4945, 4951, 4952, 4955, 4958, 4961, 4963, 4971, and 4975, and the regulations thereunder, a decision in a suit for refund instituted under the provisions of this section shall be final—

(1) Upon the expiration of the time allowed for filing a notice of appeal from a decision of the United States Claims Court or of the United States District Court, if no timely notice of appeal is filed; or

(2) Upon the expiration of the time allowed for filing a petition for certiorari from a decision of the United States Claims Court, or from a decision of the United States District Court, which has been affirmed or the appeal dismissed by the United States Court of Appeals, if no timely petition for certiorari is filed; or

(3) If a petition for certiorari has been filed, thirty days from the denial of such petition; or

(4) Thirty days from the date of a decision of the United States Supreme Court if no timely petition for rehearing is filed; however, if a timely petition for rehearing from such a decision is filed, and is denied, thirty days from the denial thereof; or

(5) If a decision is entered upon a rehearing or if a decision is modified or reversed as the result of a decision of a higher court, upon the expiration, with respect to the decision on rehearing or the modified or reversed decision, of periods similar to those provided in subparagraphs (1) through (4).

(b) Right to bring action. With respect to any taxable event, payment of the full amount of first tier tax for the taxable period shall constitute sufficient payment in order to maintain an action under this section with respect to the second tier tax.

(c) Limitation on suit for refund. No suit may be maintained under this section for the credit or refund of any tax imposed under section 4941, 4942, 4943, 4944, 4945, 4951, 4952, 4955, 4958, 4971, or 4975 with respect to any taxable event unless—

(1) No other suit has been maintained for credit or refund of any tax imposed by such sections with respect to such taxable event; and

(2) No petition has been filed in the Tax Court with respect to a deficiency in any tax imposed by such sections with respect to such taxable event.

(d) Final determination of issues. For purposes of this section, any suit for the credit or refund of any tax imposed under section 4941, 4942, 4943, 4944, 4945, 4951, 4952, 4955, 4958, 4971, or 4975, together with a supplemental proceeding (if any) under section 4961 (b), with respect to any taxable event, shall constitute a suit to determine all questions with respect to any other tax imposed with respect to such taxable event under such sections. Consequently, failure by the parties to the suit to bring before the Court any question described in the preceding sentence shall constitute a bar to the question.

(e) Definitions. For definitions of the terms “taxable event,” “first tier tax,” and “second tier tax,” see §53.4963-1.

[T.D. 8084, 51 FR 16305, May 2, 1986, as amended by T.D. 8628, 60 FR 62213, Dec. 5, 1995; T.D. 8920, 66 FR 2171, Jan. 10, 2001]