(1) Timely petition for review or certiorari not filed on time. Upon the expiration of time allowed for filing a petition for review with the United States Court of Appeals, or a petition for certiorari with the United States Supreme Court, if no such petition has been duly filed within such time; or
(2) Petition for certiorari denied. Upon the denial of a petition for certiorari by the United States Supreme Court; or
(3) Decision affirmed by Supreme Court. Upon the expiration of 30 days from the date of issuance of a mandate of the Supreme Court which has the effect of affirming the decision of the district court.
(4) Reversal of modification of decision by the Supreme Court. If the Supreme Court issues a mandate which results in the reversal or modification of the decision of the district court, the decision of the district 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 Director or the taxpayer has instituted proceedings to have such decision corrected to accord with the mandate, in which event the decision of the district court shall become final when so corrected.
(5) Rehearing. If the Supreme Court orders a rehearing or if the case is remanded by any reviewing court to the district court for a rehearing, and if—
(A) the time allowed for filing a petition for review or certiorari has expired and no such petition has been duly filed; or
(B) the petition for certiorari has been denied; or
(C) the decision of the reviewing court has been affirmed by the Supreme Court—
then the decision of the district court rendered upon such rehearing shall become final in the same manner as though no prior decision of the court has been rendered.(6) Definition of “mandate”. 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.