Key Takeaways
- UnitedHealth Group has the most Medicare Advantage members, 9.35 million or 26% of the market in October 2026, according to CMS data.
- UnitedHealth Group, Humana and CVS Health Corporation together enroll 58% of the 36.02 million people in Medicare Advantage, according to CMS.
- Medicare Advantage enrollment is up 2.6% from October 2025; among the largest insurers, Humana added the most members and UnitedHealth Group lost the most.
- Counted from CMS's enrollment by contract, grouped by the parent organization CMS records for each contract.
UnitedHealth Group has more Medicare Advantage members than any other insurer: 9.35 million, or 26% of the market, in October 2026, according to CMS. With Humana and CVS Health Corporation, three insurers enroll 58% of the 36.02 million people in Medicare Advantage.
Every figure is from CMS's monthly enrollment by contract for October 2026, with each contract counted under the parent organization CMS records for it.
The 30 largest Medicare Advantage insurers
Insurers are ranked by their Medicare Advantage enrollees across all their contracts with CMS. The change column compares each with October 2025, where CMS records the same parent organization.
| Rank | Insurer (parent organization) | Enrollees | Share of Medicare Advantage | Change from a year earlier | Contracts | Source |
|---|---|---|---|---|---|---|
| 1 | UnitedHealth Group | 9,354,348 | 26.0% | −926,555 (−9%) | 64 | CMS |
| 2 | Humana | 7,193,570 | 20.0% | +1,378,728 (+24%) | 38 | CMS |
| 3 | CVS Health Corporation | 4,175,687 | 11.6% | −17,359 (0%) | 42 | CMS |
| 4 | Kaiser Foundation Health Plan | 2,077,542 | 5.8% | +90,242 (+5%) | 11 | CMS |
| 5 | Elevance Health | 1,900,794 | 5.3% | −343,516 (−15%) | 46 | CMS |
| 6 | Centene Corporation | 910,693 | 2.5% | −62,172 (−6%) | 67 | CMS |
| 7 | Health Care Service Corporation | 899,839 | 2.5% | −60,076 (−6%) | 25 | CMS |
| 8 | Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 673,684 | 1.9% | −123,443 (−15%) | 8 | CMS |
| 9 | Devoted Health | 541,337 | 1.5% | +332,890 (+160%) | 42 | CMS |
| 10 | SCAN Group | 465,374 | 1.3% | +153,955 (+49%) | 8 | CMS |
| 11 | Highmark Health | 424,853 | 1.2% | −61,497 (−13%) | 9 | CMS |
| 12 | MHH Healthcare | 380,150 | 1.1% | +30,379 (+9%) | 2 | CMS |
| 13 | Healthfirst | 374,633 | 1.0% | +11,954 (+3%) | 4 | CMS |
| 14 | Lifetime Healthcare | 335,053 | 0.9% | +52,201 (+18%) | 5 | CMS |
| 15 | Alignment Healthcare USA | 301,157 | 0.8% | +71,212 (+31%) | 8 | CMS |
| 16 | Aware Integrated | 298,167 | 0.8% | +91,796 (+44%) | 2 | CMS |
| 17 | Corewell Health | 286,894 | 0.8% | +32,274 (+13%) | 3 | CMS |
| 18 | Guidewell Mutual Holding Corporation | 262,131 | 0.7% | −10,664 (−4%) | 5 | CMS |
| 19 | UPMC Health System | 226,649 | 0.6% | −2,321 (−1%) | 4 | CMS |
| 20 | Molina Healthcare | 221,887 | 0.6% | +1,919 (+1%) | 21 | CMS |
| 21 | BlueCross BlueShield of Tennessee | 220,412 | 0.6% | +10,544 (+5%) | 2 | CMS |
| 22 | CuraCor Solutions | 185,008 | 0.5% | +17,817 (+11%) | 4 | CMS |
| 23 | Clover Health Holdings | 158,983 | 0.4% | +49,484 (+45%) | 2 | CMS |
| 24 | Independence Health Group | 149,662 | 0.4% | −4,721 (−3%) | 10 | CMS |
| 25 | Point32Health | 147,644 | 0.4% | −298 (0%) | 6 | CMS |
| 26 | Medica Holding Company | 142,222 | 0.4% | +57,264 (+67%) | 4 | CMS |
| 27 | Henry Ford Health System | 133,524 | 0.4% | +46,865 (+54%) | 3 | CMS |
| 28 | Network Health | 133,481 | 0.4% | +46,367 (+53%) | 3 | CMS |
| 29 | California Physicians' Service | 124,189 | 0.3% | −12,110 (−9%) | 4 | CMS |
| 30 | Risant Health | 119,070 | 0.3% | +614 (+1%) | 5 | CMS |
Download this table (CSV), free. The full dataset, every Medicare Advantage contract with its organization, parent and enrollment, is one email away.
How concentrated Medicare Advantage is
- The largest five insurers enroll 69% of Medicare Advantage members, the largest ten 78%; CMS records 166 parent organizations across 703 contracts.
- Enrollment is up 2.6% from October 2025, when it stood at 35.12 million, according to CMS.
- Among the twenty largest insurers, Humana added the most members over the year (+1,378,728 members) and UnitedHealth Group lost the most (−926,555 members).
- The smallest insurer in the table enrolls 119,070 members.
What this means for technology buyers
Medicare Advantage runs on claims, enrollment and distribution systems built for CMS's rules. These guides compare the options:
- Claims management systems for health insurers: adjudicating and paying claims at plan scale.
- Document management for insurance claims: the records behind every claim and appeal.
- Regulatory compliance software for insurers: keeping up with CMS audits and filings.
Mapping the business? The Health Insurance Capability Model sets out what a health plan does, and the Health Insurance Value Streams show how that work runs end to end.
More from Finantrix Atlas
How this list was built
The universe is every contract in CMS's monthly enrollment by contract of the types CMS counts as Medicare Advantage: local and regional coordinated care plans, private fee-for-service plans and medical savings account plans. Cost plans, PACE and stand-alone drug plans are left out, as CMS leaves them out of its own Medicare Advantage subtotal. Each contract is counted under the parent organization CMS records. The total was checked against CMS's separately published summary report for the same month.
Limits
- CMS's grouping. Insurers are grouped as CMS records each contract's parent. A plan sold under one brand but owned by another company is counted under its owner.
- Small contracts. CMS does not publish enrollment of ten or fewer for a contract, so the total here can fall a few members short of CMS's summary report.
- Names as recorded. A parent renamed in the past year shows no year-earlier change.
- One month. Enrollment moves most at the start of each year, after the annual enrollment period.
Cite this
Free to quote, cite and republish, including the chart, with credit to Finantrix Atlas and a link to this page.
UnitedHealth Group has 9.35 million Medicare Advantage members, 26% of the market in October 2026, according to a Finantrix Atlas analysis of CMS enrollment data.
Three insurers enroll 58% of the 36.02 million people in Medicare Advantage, according to Finantrix Atlas.
Suggested citation: Finantrix Atlas, "Largest Medicare Advantage Insurers by Enrollment," October 2026, from CMS monthly enrollment by contract. https://www.finantrix.com/articles/largest-medicare-advantage-insurers
Embed the chart:
<a href="https://www.finantrix.com/articles/largest-medicare-advantage-insurers"><img src="https://www.finantrix.com/atlas/largest-medicare-advantage-insurers.png" alt="The largest Medicare Advantage insurers by enrollment, from Finantrix Atlas"></a>
<p>Chart: <a href="https://www.finantrix.com/articles/largest-medicare-advantage-insurers">Finantrix Atlas</a>, from CMS enrollment data.</p>
Frequently asked questions
Q: Which company has the most Medicare Advantage members? A: UnitedHealth Group, with 9.35 million members in October 2026, according to CMS.
Q: How many people are in Medicare Advantage? A: According to CMS, 36.02 million people were enrolled in Medicare Advantage plans in October 2026.
Q: How concentrated is Medicare Advantage? A: Three insurers enroll 58% of members and the largest ten 78%, according to CMS data.
Download the data
The 30 rows on this page (CSV), free. The full dataset has all 703 rows, as of October 1, 2026; we email you a link.
Frequently Asked Questions
Which company has the most Medicare Advantage members?
UnitedHealth Group, with 9.35 million members in October 2026, according to CMS.
How many people are in Medicare Advantage?
According to CMS, 36.02 million people were enrolled in Medicare Advantage plans in October 2026.
How concentrated is Medicare Advantage?
Three insurers enroll 58% of members and the largest ten 78%, according to CMS data.