The US Supreme Court has rejected the Patent Trial and Appeal Board’s (PTAB’s) practice of issuing partial institution decisions for inter partes reviews (IPRs). Issued on April 24, the Court’s 5-4 majority opinion in SAS Institute v. Iancu held that the relevant statutes from the Patent Act, as amended by the America Invents Act, do not support the USPTO’s reading that the director may elect to institute trial on just a subset of the claims challenged in an IPR petition. The majority also rejected each of the USPTO director’s arguments in favor of the partial institution power, holding that the Court’s 2016 decision in Cuozzo Speed Technologies v. Lee does not bar judicial review of any institution-related issue and that the statutes at issue were not sufficiently ambiguous to trigger Chevron deference. The Court issued its opinions—including dissents by Justices Ruth Bader Ginsburg and Stephen Breyer—on the same day that it decided Oil States Energy Services v. Greene’s Energy Group, affirming IPR’s constitutionality.