Medicare Advantage enrollment has been on a steady climb for the past two decades following changes in policy designed to encourage a robust role for private plan options in Medicare. After a period of some instability in terms of plan participation and enrollment, The Medicare Modernization Act of 2003 created stronger financial incentives for plans to participate in the program throughout the country and renamed private Medicare plans Medicare Advantage. In 2024, 32.8 million people are enrolled in a Medicare Advantage plan, accounting for more than half, or 54 percent, of the eligible Medicare population, and $462 billion (or 54%) of total federal Medicare spending (net of offsetting receipts, such as premiums). Medicare Advantage enrolls a disproportionate share of people of color in Medicare as well as an increasing number of dual eligible beneficiaries. The average Medicare beneficiary in 2024 has access to 43 Medicare Advantage plans, the same as in 2023, but more than double the number of plans offered in 2018.
The growth in Medicare Advantage enrollment is due to a number of factors, including the availability of plans that charge no premium (other than the Part B premium), and extra benefits offered by most Medicare Advantage plans. Nearly all Medicare Advantage plans offer some benefits not included in traditional Medicare, such as coverage of dental, vision, or hearing services, often for no additional premium. Medicare beneficiaries are also drawn to the financial protection that comes with an out-of-pocket limit, which Medicare Advantage plans are required to provide, while traditional Medicare has no out-of-pocket cap on spending. On the other hand, Medicare Advantage plans have limited provider networks and apply cost management tools such as prior authorization, which traditional Medicare does not.
Generally, research shows that Medicare pays more to private Medicare Advantage plans for enrollees than their costs would be in traditional Medicare. The Medicare Payment Advisory Commission (MedPAC) reports that plans receive payments from CMS that are 122% of spending for similar beneficiaries in traditional Medicare, on average, translating to an estimated $83 billion in higher spending in 2024. As Medicare Advantage takes on a more dominant presence in the Medicare program, and with current payments to plans higher for Medicare Advantage than for traditional Medicare for similar beneficiaries, policymakers have become increasingly focused on how well Medicare’s current payment methodology for Medicare Advantage is working to enhance efficiency and hold down beneficiary costs and Medicare spending.
To better understand trends in the growth of the program, this brief provides current information about Medicare Advantage enrollment, by plan type and firm, and shows how enrollment varies by state and county. A second, companion analysis describes Medicare Advantage premiums, out-of-pocket limits, supplemental benefits offered, and prior authorization requirements in 2024. This analysis does not provide detailed information by enrollee characteristics, such as race/ethnicity, income, or dual status, because that information is not available.
Highlights for 2024:
- More than half (54%) of eligible Medicare beneficiaries are enrolled in Medicare Advantage in 2024. The share of Medicare beneficiaries in Medicare Advantage plans varies across states, ranging from 2% to 63%. In 7 states, AL, CT, MI, HI, ME, FL, RI (and Puerto Rico), 60% or more of all Medicare beneficiaries are enrolled in Medicare Advantage plans, an increase from 3 states in 2023.
- More than one-third (37%) of Medicare beneficiaries live in a county where at least 60 percent of all Medicare beneficiaries are enrolled in Medicare Advantage plans. Three counties (excluding those in Puerto Rico) enroll 80% or more of Medicare beneficiaries in Medicare Advantage plans: Monroe County, NY (Rochester; 82%), Starr, Texas (81%), and Miami-Dade County, Florida (80%). At the same time, 8 percent of all Medicare beneficiaries nationwide live in a county with relatively low enrollment, where less than one third of all Medicare beneficiaries are enrolled in Medicare Advantage plans. The wide variation in county enrollment rates reflect several factors, such as differences in firm strategy, urbanicity of the county, Medicare payment rates, number of Medicare beneficiaries, health care use patterns, and historical Medicare Advantage market penetration.
- Medicare Advantage enrollment is highly concentrated among a small number of firms, with UnitedHealthcare and Humana accounting for nearly half (47%) of all Medicare Advantage enrollees nationwide. In more than a quarter of all U.S. counties (29%; or 931 counties), these two firms account for at least 75 percent of Medicare Advantage enrollment. Since 2017, the market share for UnitedHealthcare and CVS Health has increased (25% to 29% and 8% to 12%, respectively), Humana (18%) and Cigna (2%) have held steady, while other firms’ share of total enrollment has slightly decreased (Blue Cross Blue Shield (BCBS) affiliates, Kaiser Permanente, and Centene). Small firms (which each account for less than 2% of enrollment) have a smaller share of the market in 2024 than in 2017 (19% to 16%).
More than half of eligible Medicare beneficiaries are enrolled in Medicare Advantage in 2024
In 2024, more than half (54%) of eligible Medicare beneficiaries – 32.8 million people out of 61.2 million Medicare beneficiaries with both Medicare Parts A and B – are enrolled in Medicare Advantage plans. Medicare Advantage enrollment as a share of the eligible Medicare population has jumped from 19% in 2007 to 54% in 2024.
In 2024, nearly two-thirds of Medicare Advantage enrollees are in individual plans that are open for general enrollment.
More than 6 in 10 Medicare Advantage enrollees (62%), or 20.5 million people, are in plans generally available to all beneficiaries for individual enrollment (Figure 3). That is an increase of 0.9 million enrollees compared to 2023. Individual plans have declined as a share of total Medicare Advantage enrollment since 2010 (71%).