Enrollment in Medicare Advantage, the private plan alternative to traditional Medicare, has increased steadily over the past two decades, with more than half of eligible beneficiaries enrolled in Medicare Advantage since 2023. The growth in enrollment has implications for federal spending, because according to the Medicare Payment Advisory Commission (MedPAC), Medicare payments to private plans are higher than spending for similar beneficiaries in traditional Medicare. In 2025, payments are 20% more per person, which translates into an additional $84 billion in federal spending this year, substantially larger than the $18 billion in higher spending a decade ago when about one-third of eligible beneficiaries were enrolled in a Medicare Advantage plan.
Given the enrollment and spending trends, policymakers have become increasingly focused on how Medicare pays private plans, though without broad agreement on how or when to move forward. In part, the difficulty stems from concerns about the effects of payment changes for beneficiaries’ choice among plans and access to supplemental benefits, such as coverage of dental, vision and hearing.
Highlights for 2025
- More than half (54%) of eligible Medicare beneficiaries are enrolled in Medicare Advantage in 2025. While a growing share of Medicare beneficiaries are enrolled in a Medicare Advantage plan, the pace of the increase in enrollment slowed in 2025.
- In 2025, one in five (21%) Medicare Advantage enrollees is in a special needs plan (SNP), reflecting a steady increase in recent years. Almost half (48%) of the total increase in Medicare Advantage enrollment between 2024 and 2025 was among SNPs, up from 43% in the prior year.
- More than 80% of SNP enrollment is in plans designed for people who are dually eligible for Medicare and Medicaid (D-SNPs), though plans for people with certain chronic conditions (C-SNPs) saw a surge in enrollees in 2025. Enrollment in C-SNPS increased by more than 70% between 2024 and 2025, compared to 3% for D-SNPs and 0% for institutional-SNPs.
- Medicare Advantage enrollment is highly concentrated among plans owned by a small number of parent organizations, with UnitedHealth Group leading the market, and, together with Humana, accounting for nearly half (46%) of all Medicare Advantage enrollees nationwide, consistent with the pattern in 2024. Since 2024, market shares for the leading parent organizations have remained roughly the same. However, in absolute numbers, UnitedHealth Group had the largest growth in enrollment, with 505,000 more enrollees in 2024 than in 2025, followed by Elevance Health, which gained 249,000 enrollees. In contrast, enrollment in Humana plans decreased by about 297,000 between 2024 to 2025.