The Regional Greenhouse Gas Initiative (RGGI) is a cooperative effort of nine Northeast and Mid-Atlantic states to regulate and reduce carbon dioxide (CO2) emissions from the power sector. In accordance with each state’s independent legal authority, Connecticut, Delaware, Maine, Massachusetts, Maryland, New Hampshire, New York, Rhode Island, and Vermont (Participating States) each commit to propose statutory and/or regulatory approval revisions to their CO2 Budget Trading Programs substantially consistent with the updated Model Rule released on December 19, 2017 (updated 2017 Model Rule). The Participating States further agree on principles that will guide the states in proposing these revisions, in working together to implement their CO2 Budget Trading Programs, and in seeking to reduce greenhouse gas emissions in the region.