The United States Patent and Trademark Office (USPTO or Office) proposes modifications to the rules of practice for inter partes review (IPR) and post-grant review (PGR) proceedings before the Patent Trial and Appeal Board (PTAB or Board) that the Director and, by delegation, the PTAB will use in exercising discretion to institute IPRs and PGRs. The Office proposes these provisions in light of stakeholder feedback received in response to a Request for Comments (RFC) and an Advance Notice of Proposed Rulemaking (ANPRM). The proposals enhance and build on existing precedent and guidance regarding the exercise of the Director’s discretion pursuant to the America Invents Act (AIA) to determine whether to institute an IPR or PGR proceeding with regard to serial petitions, parallel petitions, and petitions implicating the same or substantially the same art or arguments previously presented to the Office. The proposed rules also provide a separate briefing process for discretionary institution arguments and align the procedures for termination of proceedings pre- and post-institution.