Largest Medicare Advantage Companies in the U.S. by Enrollment 2026
Medicare Advantage Enrollment Leaders and Market Concentration in 2026
UnitedHealth Group leads the September 2026 national parent-organization enrollment display with 9,326,279 enrollees, followed by Humana with 7,191,929 and CVS Health with 4,156,589. Higher enrollment ranks higher.
This page ranks 10 confirmed parent organizations. The exact September ranking values are published by BARA Analytics from CMS-derived monthly enrollment data. CMS confirms the September 2026 source releases, while KFF provides an independent March 2026 Medicare Advantage benchmark and parent-organization methodology.
The unit is enrolled members and the snapshot is September 2026. All 10 ranking rows use observed industry values. No forecast, modeled projection, CAGR, interpolation or synthetic enrollment estimate is used.
This is a confirmed Top 10, not a Top 100. Ranks 11–100 are not included because a consistent 100-row September 2026 parent-organization dataset has not been verified.
UnitedHealth Group, Inc. ranks first.
SCAN Group is the opposite extreme within the confirmed Top 10.
Ten parent organizations with September 2026 values.
September 2026 · BARA ranking values · CMS-derived data.
Share of the 36,183,289-member September parent-organization denominator.
10 industry-observed values · 0 forecasts · 0 modeled projections.
What this Medicare Advantage enrollment ranking measures
The ranking measures enrollment at the parent-organization level rather than at the individual CMS contract or plan level. One parent company can control multiple legal entities and CMS contracts, so a parent-level view is useful for comparing the scale of the largest Medicare Advantage companies and insurers.
The controlling organization associated with one or more entities that contract with CMS.
An operating contract between CMS and an organization. A single parent organization can control multiple contracts.
A private Medicare coverage option offered under a CMS contract. One contract can contain multiple plan benefit packages.
The number of members reported in the monthly snapshot. It measures organizational scale, not plan quality.
Enrollment should not be interpreted as a quality score. A larger Medicare Advantage insurer does not automatically offer better premiums, benefits, provider networks, Star Ratings, member experience or clinical outcomes.
Medicare Advantage Market Share by Company
The confirmed September values show substantial concentration among the largest parent organizations. The percentages below use the 36,183,289-member national parent-organization denominator displayed by BARA Analytics.
Concentration calculated from the confirmed September 2026 ranking
| Measure | Enrollment | Share | Method Note |
|---|---|---|---|
| UnitedHealth Group | 9,326,279 | 25.8% | September 2026 value and share published in the BARA national parent display. |
| Top 2 combined | 16,518,208 | 45.7% | UnitedHealth Group plus Humana divided by 36,183,289. |
| Top 3 combined | 20,674,797 | 57.1% | UnitedHealth Group, Humana and CVS Health combined. |
| Confirmed Top 10 | 28,096,481 | 77.7% | Sum of all confirmed Top 10 rows divided by 36,183,289. |
Combined enrollment and shares are calculated from the observed September ranking values. They are analytical summaries, not forecasts.
Chart: Top 10 Medicare Advantage Organizations by Enrollment
The chart uses the same raw enrollment values as the ranking table. UnitedHealth Group has about 20.3 times the enrollment of SCAN Group, the No. 10 organization in the confirmed dataset.
Methodology, Source Hierarchy and Limitations
Ranking metric: enrollment by parent organization. Unit: enrolled members. Target snapshot: September 2026. Direction: descending. Exact ranking values come from the September national parent-organization display published by BARA Analytics. CMS and KFF are validation and methodology sources rather than alternative sources for the exact September Top 10 values.
Ranking source
BARA Analytics displays September 2026 national parent-organization enrollment totaling 36,183,289 members and publishes the exact values used for ranks 1–10.
Official CMS validation
CMS confirms that September 2026 Monthly Enrollment by Contract and other monthly enrollment releases are available. CMS monthly plan and contract datasets cover multiple organization types, so they are not treated here as a ready-made parent-company ranking.
Independent MA benchmark
KFF's March 2026 analysis uses CMS data and includes HMOs, local and regional PPOs, PFFS plans and MSAs. KFF reports 35.2 million Medicare Advantage enrollees in March 2026.
Parent ownership
KFF states that its parent-organization analysis relies on the parent-organization field reported to CMS to group plans sponsored by the same insurer.
How to read the ranking
The published September enrollment values are sorted from highest to lowest using raw whole-member counts. A larger value receives a higher rank. No value is projected or rounded before ranking.
Concentration calculations on this page use: combined share = confirmed organization enrollment sum ÷ 36,183,289 × 100.
Why BARA and KFF totals are different
BARA's national parent display uses September 2026 values. KFF's independent Medicare Advantage analysis uses March 2026 data and a separately defined methodology. KFF reports 35.2 million Medicare Advantage enrollees in March 2026, so the KFF total should not be substituted for BARA's September denominator.
Why BARA shows two different September enrollment totals
BARA's September geographic penetration section reports 35,842,815 enrolled beneficiaries, while its separate national parent-organization section reports 36,183,289. BARA states that plan enrollment is sourced separately from the geography-based penetration calculation. This ranking uses 36,183,289 only for calculations tied to the parent-organization table.
Source-version limitation
The live BARA ranking displays September 2026 values, while explanatory text elsewhere on the same tool still refers to its August 2026 release. CMS independently confirms that September 2026 enrollment files are available. The September values are therefore treated as observed industry ranking data, not as official CMS-published parent totals.
Plan-type boundary
The September BARA parent display should not be assumed to have exactly the same inclusion rules as KFF's March Medicare Advantage dataset. BARA's explanatory material discusses a small residual share of 1876 Cost plans in its broader HMO/PPO market view, but that explanation is tied to its August methodology text rather than a separately documented September parent-ranking specification.
KFF provides the stricter Medicare Advantage benchmark used for context. Its 2026 analysis includes HMO, PPO, PFFS and MSA enrollment and excludes Cost plans, PACE, HCPPs and MMPs. Special Needs Plans are part of Medicare Advantage enrollment.
Missing values and suppression
No missing organization is assigned a synthetic value and no conflicting values are averaged. KFF notes that its county-level methodology excludes plan-county combinations with fewer than 11 beneficiaries. That KFF suppression rule is not applied to the BARA national parent-organization values displayed on this page.
What this metric does not measure
Enrollment measures organizational size. It does not measure plan quality, Star Ratings, premiums, supplemental benefits, provider-network breadth, prior authorization, member satisfaction, profitability or clinical outcomes. It is a monthly snapshot, not an annual unique-beneficiary count.
Top 10 Medicare Advantage Companies by Enrollment
The full confirmed September 2026 ranking is shown below. Search by parent organization or consumer-facing brand name, or change the sort order. Without JavaScript, every row remains visible.
Confirmed September 2026 parent-organization enrollment
| Rank | Parent Organization | Enrollment | Source / Method Note |
|---|---|---|---|
| 1 | UnitedHealth Group, Inc. | 9,326,279 | Industry observed · BARA · Sep 2026 · target Sep 2026. |
| 2 | Humana Inc. | 7,191,929 | Industry observed · BARA · Sep 2026 · target Sep 2026. |
| 3 | CVS Health Corporation | 4,156,589 | Industry observed · BARA · Sep 2026 · target Sep 2026 · Aetna parent. |
| 4 | Kaiser Foundation Health Plan, Inc. | 2,070,279 | Industry observed · BARA · Sep 2026 · target Sep 2026. |
| 5 | Elevance Health, Inc. | 1,889,737 | Industry observed · BARA · Sep 2026 · target Sep 2026 · Anthem brands. |
| 6 | Centene Corporation | 913,730 | Industry observed · BARA · Sep 2026 · target Sep 2026. |
| 7 | Health Care Service Corporation | 886,374 | Industry observed · BARA · Sep 2026 · target Sep 2026. |
| 8 | Blue Cross Blue Shield of Michigan Mutual Ins. Co. | 669,751 | Industry observed · BARA · Sep 2026 · target Sep 2026. |
| 9 | Devoted Health, Inc. | 531,396 | Industry observed · BARA · Sep 2026 · target Sep 2026. |
| 10 | SCAN Group | 460,417 | Industry observed · BARA · Sep 2026 · target Sep 2026. |
Ranking source for all rows: BARA Analytics, September 2026 national parent-organization display. Values are raw whole-member counts. No forecast, interpolation, averaging or synthetic enrollment value is used.
Insights from the September 2026 Top 10
Key Insight
UnitedHealth Group leads Humana by 2,134,350 enrollees in the September parent-organization display.
Notable Pattern
UnitedHealth Group, Humana and CVS Health together total 20,674,797 enrollees, approximately 57.1% of the September parent-ranking denominator.
Market Concentration
The confirmed Top 10 account for 28,096,481 enrollees, approximately 77.7% of the 36,183,289-member parent-organization display.
Outlier
UnitedHealth Group's enrollment is approximately 20.3 times SCAN Group's, showing a large scale gap even among the ten largest confirmed organizations.
How to Read the Ranking and Why Companies Differ
A parent organization's position reflects enrollment associated with businesses and contracts grouped under that parent. The corporate parent can differ from the consumer-facing insurance brand. Aetna, for example, is part of CVS Health, while Anthem-branded businesses are associated with Elevance Health.
Medicare Advantage companies can differ in enrollment because they operate across different states and counties, control different numbers of CMS contracts, and participate in different mixes of individual plans, employer or union group plans and Special Needs Plans. These structural differences affect scale but do not by themselves prove why a company gained or lost members.
KFF's independent March 2026 Medicare Advantage analysis supports the broader concentration pattern. KFF reports UnitedHealth Group at 26% of MA enrollment, Humana at 20%, CVS Health at 12%, Kaiser at 6% and Elevance at 5%. UnitedHealth Group and Humana together represented 46% of KFF's March 2026 Medicare Advantage enrollment.
Monthly enrollment can change during the year, and parent ownership can change through acquisitions or corporate restructuring. This ranking should therefore be read as a September 2026 snapshot rather than a permanent market hierarchy.
FAQ
What is the largest Medicare Advantage company in the U.S.?
UnitedHealth Group ranks first in the September 2026 parent-organization display used for this ranking, with 9,326,279 enrollees.
What are the largest Medicare Advantage companies in 2026?
The confirmed September Top 10 are UnitedHealth Group, Humana, CVS Health, Kaiser Foundation Health Plan, Elevance Health, Centene, Health Care Service Corporation, Blue Cross Blue Shield of Michigan, Devoted Health and SCAN Group.
What is Medicare Advantage market share by company?
In the September BARA parent-organization display, UnitedHealth Group represents 25.8% of the 36,183,289-member denominator. UnitedHealth and Humana together represent approximately 45.7%, while the confirmed Top 10 represent approximately 77.7%.
Are these official CMS parent-organization totals?
No. CMS publishes the underlying monthly enrollment datasets, but the exact September parent-organization totals shown here are published by BARA Analytics. CMS is used to validate the September source period and reporting structure.
Is this ranking the same as KFF's 2026 Medicare Advantage dataset?
No. KFF uses March 2026 data and its own Medicare Advantage methodology. This ranking uses September parent-organization values displayed by BARA Analytics. KFF is used as an independent benchmark rather than as the source of the September values.
Does the ranking include stand-alone Medicare Part D plans?
Stand-alone PDP enrollment is not treated as Medicare Advantage enrollment for interpretation on this page. CMS maintains separate Part D reporting. The BARA parent display should nevertheless not be assumed to have exactly the same plan-type boundaries as KFF's strict Medicare Advantage methodology.
Why do 35,842,815 and 36,183,289 both appear in BARA's data?
The first figure belongs to BARA's geographic penetration calculation. The second belongs to its separate national parent-organization enrollment display. This page uses 36,183,289 only for calculations tied to the parent ranking.
Why are Aetna and Anthem not separate parent organizations?
The ranking uses parent organizations rather than every consumer-facing brand. Aetna is part of CVS Health, while Anthem-branded businesses are associated with Elevance Health.
Are Special Needs Plans part of Medicare Advantage?
Yes. KFF reports that 23% of Medicare Advantage enrollees were in Special Needs Plans in 2026.
Does larger enrollment mean a better Medicare Advantage plan?
No. Enrollment measures organizational size. It does not measure premiums, benefits, provider access, Star Ratings, member experience, prior authorization or clinical quality.
Why is this a Top 10 instead of a Top 100?
A valid Top 100 requires 100 parent organizations measured for the same period with consistent scope and provenance. Only ten September 2026 parent-level values are currently confirmed from the ranking source, so ranks 11–100 are not invented.
Sources
BARA Analytics
Ranking source for the exact September 2026 parent-organization values, published company shares and the 36,183,289-member national parent-organization denominator.
Centers for Medicare & Medicaid Services
Official validation source confirming September 2026 contract and plan enrollment releases and the CMS monthly reporting structure.
KFF
Independent March 2026 Medicare Advantage benchmark used for parent-organization concentration, plan-type methodology, SNP context and comparison with the September ranking.
https://www.kff.org/medicare/medicare-advantage-in-2026-enrollment-update-and-key-trends/
