Skip to content In brief The US Court of Appeals for the First Circuit in Kyick Holdings, LLC v. Commissioner, 188 F.4th 39 (1st Cir. 2026)affirmed the dismissal of Kyick Holdings, LLC’s untimely Tax Court petition to contest a notice of transferee liability, but rejected the Tax Court’s conclusion that the 90-day deadline in section 6213(a) is jurisdictional. The First Circuit held that the deadline is a nonjurisdictional claim-processing rule, yet is mandatory and cannot be equitably tolled.