Opinion of the Court
ence on March 2 (10 days after the decertification order) that he would “want to file a motion for reconsideration” in the near future. App. to Pet. for Cert. 74. The court told Lambert to file any such motion “no later than” March 12. Id., at 76. Neither Lambert nor the District Court mentioned the possibility of an appeal.
Lambert filed his motion for reconsideration, in compliance with the District Court’s schedule, on March 12 (20 days after the decertification order). The District Court denied the motion on June 24, 2015. Fourteen days later, on July 8, Lambert petitioned the Court of Appeals for permission to appeal the decertification order. Nutraceutical’s response argued that Lambert’s petition was untimely because more than four months had elapsed since the District Court’s February 20 order decertifying the class, far more than the 14 days that Federal Rule of Civil Procedure 23(f) allows. App. 41.
Notwithstanding the petition’s apparent untimeliness, the Court of Appeals “deem[ed] Lambert’s petition timely” because, in its view, the Rule 23(f) deadline should be “tolled” under the circumstances. 870 F. 3d 1170, 1176 (CA9 2017). The Court of Appeals reasoned that Rule 23(f)’s time limit is “non-jurisdictional, and that equitable remedies softening the deadline are therefore generally available.” Ibid. Tolling was warranted, the court concluded, because Lambert “informed the [District Court] orally of his intention to seek reconsideration” within Rule 23(f)’s 14-day window, complied with the District Court’s March 12 deadline, and “otherwise acted diligently.” Id., at 1179. On the merits, the Court of Appeals held that the District Court abused its discretion in decertifying the class. Id., at 1182–1184. It reversed the decertification order. Id., at 1184.
In accepting Lambert’s petition, the Court of Appeals
