The Department of Health and Human Services (HHS) and the Treasury Department released joint guidance describing standards for reviewing State Innovation Waiver applications. The waivers—also called 1332 waivers—permit states to waive certain ACA requirements related to Marketplaces, federal subsidies, qualified health plans, and the individual and employer mandates, contingent on meeting certain statutory “guardrails.” New details about the statutory guardrails appear to limit the types of 1332 waivers that can be approved. Significantly, the guidance requires states to consider the waiver alone when calculating its impact on the federal deficit, limiting states’ abilities to incorporate potential Medicaid savings into calculations. Additionally, states are required to consider the impact on the state as a whole and on subgroups (such as the poor and elderly) to ensure each subgroup is not negatively impacted for comprehensiveness, affordability and coverage. Finally, the guidance notes that HHS and the Treasury will not be able to customize Federally-facilitated Marketplace and IRS practices and procedures for specific state waivers.