This rule continues to implement the hydrofluorocarbon (HFC) phasedown under the American Innovation and Manufacturing (AIM) Act. A prior rulemaking established a framework for the allowance allocation and trading program to phase down HFC production and consumption over time, and also established the production and consumption baselines, codified the list of controlled substances that will be covered by those baselines, determined an approach to allocating annual allowances for 2022 and 2023 and allowing for trading of those allowances, established recordkeeping and reporting requirements, introduced a robust, agile, and innovative compliance and enforcement system, and addressed other related elements. To continue phasing down the production and consumption of listed HFCs on the schedule listed in the AIM Act, this rulemaking determined an approach to allocating annual production and consumption allowances for calendar years 2024 through 2028, revised provisions related to the allocation methodology, amended the consumption baseline to reflect updated data, and made adjustments based on the lessons learned from implementation of the framework rule.