On April 9, 2018, the Centers for Medicare & Medicaid Services (CMS) released the long-awaited final Exchange guidance for the 2019 plan year – the final Notice of Benefit and Payment Parameters for 2019 (NBPP) and the final Letter to Issuers in the Federally-facilitated Exchanges (Letter). Together, the NBPP and Letter set forth changes to rules and operational and technical guidance for health plan regulation, Exchange operations (including plan certification and financial parameters), and premium stabilization programs. Most–but not all–of the changes take effect for the 2019 plan year.