This bill, H.R. 5243, aims to significantly increase data transparency for supplemental benefits offered through Medicare Advantage plans. It amends the Social Security Act to require Medicare Advantage organizations to submit detailed, enrollee-level data on these benefits to the Secretary of Health and Human Services, beginning with plan years starting on or after January 1, 2029. The required data includes information on eligibility , the types of benefit categories offered , and comprehensive details on utilization and payments , such as the total amount spent per enrollee and out-of-pocket costs per utilization. This granular data will be reported by item or service, or category, and include national provider identifiers. To ensure public access and utility, the bill mandates that the Secretary make this submitted data available annually to individuals and entities for program evaluations and healthcare research, starting in October 2030. Furthermore, a public use data file containing this information must be published on the Centers for Medicare & Medicaid Services website, with strict procedures in place to safeguard the privacy of any individually identifiable enrollee information.