Date when Tax Court decision becomes final

Except as provided in subsections (b), (c), and (d), the decision of the Tax Court shall become final— Upon the expiration of the time allowed for filing a notice of appeal, if no such notice has been duly filed within such time; or Upon the expiration of the time allowed for filing a petition for certiorari, if the decision of the Tax Court has been affirmed or the appeal dismissed by the United States Court of Appeals and no petition for certiorari has been duly filed; or Upon the denial of a petition for certiorari, if the decision of the Tax Court has been affirmed or the appeal dismissed by the United States Court of Appeals; or Upon the expiration of 30 days from the date of issuance of the mandate of the Supreme Court, if such Court directs that the decision of the Tax Court be affirmed or the appeal dismissed. If the Supreme Court directs that the decision of the Tax Court be modified or reversed, the decision of the Tax Court rendered in accordance with the mandate of the Supreme Court shall become final upon the expiration of 30 days from the time it was rendered, unless within such 30 days either the Secretary or the taxpayer has instituted proceedings to have such decision corrected to accord with the mandate, in which event the decision of the Tax Court shall become final when so corrected. If the decision of the Tax Court is modified or reversed by the United States Court of Appeals, and if— If the Supreme Court orders a rehearing; or if the case is remanded by the United States Court of Appeals to the Tax Court for a rehearing, and if— As used in this section, the term “mandate”, in case a mandate has been recalled prior to the expiration of 30 days from the date of issuance thereof, means the final mandate. The decision of the Tax Court in a proceeding conducted under section 7436(c) or 7463 shall become final upon the expiration of 90 days after the decision is entered. Notwithstanding subsection (a), if, within 1 year after the date the decision of the Tax Court becomes final under subsection (a) in a case to which this subsection applies, the taxpayer files a motion in the Tax Court for a redetermination of the amount of interest involved, then the Tax Court may reopen the case solely to determine whether the taxpayer has made an overpayment of such interest or the Secretary has made an underpayment of such interest and the amount thereof. This subsection shall apply where— If the Tax Court determines under this subsection that the taxpayer has made an overpayment of interest or that the Secretary has made an underpayment of interest, then that determination shall be treated under section 6512(b)(1) as a determination of an overpayment of tax. An order of the Tax Court redetermining interest, when entered upon the records of the court, shall be reviewable in the same manner as a decision of the Tax Court. If with respect to a decedent’s estate subject to a decision of the Tax Court— there is treated as an administrative expense under section 2053 either—