Medicare Advantage Penetration
Medicare Advantage enrollment and plan share by state and county, from the monthly CMS release.
About this data
What is Medicare Advantage penetration?
The share of Medicare-eligible people in an area enrolled in a Medicare Advantage plan rather than Original Medicare. Nationally it is 51.7% as of August 2026, up from 32.6% ten years ago.
How often is this updated?
Monthly. CMS publishes county enrollment and eligibility a few weeks after each month; this page is on the August 2026 release, covering 121 months of history.
Which states have the highest and lowest MA penetration?
Highest: Puerto Rico at 85%, Michigan at 64%, Alabama at 62%. Among states with more than 200,000 eligibles, the lowest are Maryland at 25%, Montana at 30%, New Hampshire at 31%. The spread between states is far wider than the national average suggests.
Is Medicare Advantage still growing?
Nationally it has stopped. Penetration is 51.7% in August 2026, down 0.1 points from a year earlier - the first flat year in the decade this page covers, after a rise from 32.6% in 2016. The change is not evenly spread: penetration fell in Idaho, Wyoming, Minnesota and New Hampshire by more than 4 points, and rose by about a point in West Virginia, Utah and Louisiana. Switch the map to “Change vs a year earlier” to see it.
Who are the largest Medicare Advantage plans?
By parent organisation, UnitedHealth Group, Inc. is the largest at 25.8% of national enrollment, and the top three hold 57.2%. Share is calculated from the CMS contract-level enrollment file for August 2026.
How much of Medicare Advantage is HMO rather than PPO?
Nationally 58% of Medicare Advantage enrollment is in an HMO and 41% in a PPO, but that split varies more by geography than the penetration rate does. Wyoming and Vermont have almost no HMO enrollment; California is 89% HMO and Puerto Rico 99%. It moves inside a state too - Florida runs from under 10% HMO in some counties to over 90% in others. The remaining 1% is mostly 1876 Cost plans, which are a third of enrollment across Minnesota and the Dakotas. The distinction matters to a provider because an HMO is a closed network with referrals and tighter utilization review, while a PPO pays out of network.
Why are some states missing?
Some months CMS does not publish eligibility counts for every state. That is a gap in the source file, not in this page: the states affected are named under the map with the month each was last published, hatched rather than shaded on the map, and excluded from the national rate rather than counted as zero. Their plan enrollment comes from a separate CMS file and is unaffected.
Why does penetration matter for skilled nursing?
Medicare Advantage pays differently from Original Medicare - negotiated rates, prior authorisation, and shorter lengths of stay. In a market where most eligibles are in MA, a facility's Medicare mix and its per diem assumptions look very different from the national averages.
What this means for a facility
This page shows a market. SNF Insights, our skilled nursing platform, shows a facility inside it — its payer mix against the market it competes in, and how its Medicare length of stay and rates compare with the facilities that actually look like it.
See SNF Insights →Source: CMS Medicare Advantage county penetration and contract enrollment files, August 2026, both public monthly releases. Counties where reported enrollment exceeds reported eligibility are excluded — CMS ships a handful every month. Figures are as published by CMS and are not adjusted or restated. BARA Analytics is independent and is not affiliated with or endorsed by CMS.