Medicare Advantage: 78% of Members in Four-Star PlansWide moat

UnitedHealth Group (UNH) — moat facet

Seventy-eight percent of UnitedHealthcare's Medicare Advantage members are in four-star plans, against 64% for the industry and 20% at Humana.

Medicare Advantage is where UnitedHealthcare's scale shows most. Its Medicare & Retirement business had revenue of $171,285 million in 2025, up 23% from $139,482 million1, and it served 8,445,000 Medicare Advantage members at the end of 20252. A trade report describes UnitedHealth Group as the largest insurer in the Medicare Advantage market3.

Members in 4-star or better MA plans, 2026 star year (%)78%UnitedHealthcare81%Aetna64%Industry20%HumanaFierce Healthcare, 2026 Medicare Advantage star ratings
Well above the industry, far above Humana.

Quality is what keeps it there. For the 2026 star year, 78% of UnitedHealthcare's Medicare Advantage members were in plans rated four stars or higher, up from 75%4, against 64% for the industry5. Humana, the second-largest player, reported 20%, down from 25%6. Star ratings affect how much the government pays a plan, so a lead in stars is a lead in revenue per member.

The business extends beyond Medicare Advantage: UnitedHealthcare enrolled 10.4 million people in Medicare Part D drug programs7 and 4,260,000 in Medicare Supplement plans at the end of June 20268.

The scale is now being cut on purpose. Medicare & Retirement revenue was $42,390 million in the second quarter of 2026, against $42,623 million a year earlier9, because the company is serving fewer seniors after repricing.

The quality score is not the only measure of the franchise. UnitedHealthcare's HouseCalls program sent nurse practitioners on 3.1 million preventive home visits in 202510, a service that reaches Medicare Advantage members at home. Humana's average star rating for 2026 was 3.61, and 14% of its members were in plans with at least 4.5 stars11.

The quality lead is the real moat here. The star share is the measure: holding near 78% while rivals slip would keep the payment advantage; a fall toward the industry's 64% would erase the one edge that does not depend on size.

Moat trajectory: Holding steady

Star share rose to 78%; membership being cut deliberately.

The number that tests this moat
Reported
Medicare & Retirement revenue, latest quarter
$42,390M (Q2 2026) vs $42,623M

The Medicare business after deliberate shrinking; falling faster than planned would mean the repricing is losing good members too.

Source: UnitedHealth Group Q2 2026 results release ↗
⚠ Threats to the moat
⚠ THREAT 01
Stars Are Re-Scored Every Year
Humana lost a fifth of its four-star membership in one re-scoring; UnitedHealthcare's lead has to survive the same test every year.
References
  1. ReportedIts Medicare & Retirement business had revenue of $171,285 million in 2025, up 23% from $139,482 million, and it served 8,445,000 Medicare Advantage members at the end of 2025.
    UnitedHealth Group Form 10-K for fiscal 2025 - Item 7 MD&A: consolidated and segment results, medical care ratio, membership and operating metrics. — FY2025 · publ. 2 March 2026 · source ↗
  2. ReportedIts Medicare & Retirement business had revenue of $171,285 million in 2025, up 23% from $139,482 million, and it served 8,445,000 Medicare Advantage members at the end of 2025.
    UnitedHealth Group Form 10-K for fiscal 2025 - Item 7 MD&A: consolidated and segment results, medical care ratio, membership and operating metrics. — FY2025 · publ. 2 March 2026 · source ↗
  3. ReportedA trade report describes UnitedHealth Group as the largest insurer in the Medicare Advantage market.
    Fierce Healthcare, '2026 MA Star Ratings: Aetna, Humana see scores decline; UnitedHealthcare improves'. — October 2025 · publ. 10 October 2025 · source ↗
  4. ReportedFor the 2026 star year, 78% of UnitedHealthcare's Medicare Advantage members were in plans rated four stars or higher, up from 75%, against 64% for the industry.
    Fierce Healthcare, '2026 MA Star Ratings: Aetna, Humana see scores decline; UnitedHealthcare improves'. — October 2025 · publ. 10 October 2025 · source ↗
  5. ReportedFor the 2026 star year, 78% of UnitedHealthcare's Medicare Advantage members were in plans rated four stars or higher, up from 75%, against 64% for the industry.
    Fierce Healthcare, '2026 MA Star Ratings: Aetna, Humana see scores decline; UnitedHealthcare improves'. — October 2025 · publ. 10 October 2025 · source ↗
  6. ReportedHumana, the second-largest player, reported 20%, down from 25%.
    Fierce Healthcare, '2026 MA Star Ratings: Aetna, Humana see scores decline; UnitedHealthcare improves'. — October 2025 · publ. 10 October 2025 · source ↗
  7. ReportedThe business extends beyond Medicare Advantage: UnitedHealthcare enrolled 10.4 million people in Medicare Part D drug programs and 4,260,000 in Medicare Supplement plans at the end of June 2026.
    UnitedHealth Group Form 10-K for fiscal 2025 - Item 1 business: segments, products, people served and leadership. — FY2025 · publ. 2 March 2026 · source ↗
  8. ReportedThe business extends beyond Medicare Advantage: UnitedHealthcare enrolled 10.4 million people in Medicare Part D drug programs and 4,260,000 in Medicare Supplement plans at the end of June 2026.
    UnitedHealth Group second-quarter 2026 results release, Form 8-K exhibit 99.1 - consolidated results, medical care ratio, cash flow, balance sheet and the raised 2026 outlook. — Q2 2026 · publ. 16 July 2026 · source ↗
  9. ReportedMedicare & Retirement revenue was $42,390 million in the second quarter of 2026, against $42,623 million a year earlier, because the company is serving fewer seniors after repricing.
    UnitedHealth Group second-quarter 2026 results release, Form 8-K exhibit 99.1 - segment results, operating metrics and people served. — Q2 2026 · publ. 16 July 2026 · source ↗
  10. ReportedUnitedHealthcare's HouseCalls program sent nurse practitioners on 3.1 million preventive home visits in 2025, a service that reaches Medicare Advantage members at home.
    UnitedHealth Group Form 10-K for fiscal 2025 - Item 7 MD&A: consolidated and segment results, medical care ratio, membership and operating metrics. — FY2025 · publ. 2 March 2026 · source ↗
  11. ReportedHumana's average star rating for 2026 was 3.61, and 14% of its members were in plans with at least 4.5 stars.
    Fierce Healthcare, '2026 MA Star Ratings: Aetna, Humana see scores decline; UnitedHealthcare improves'. — October 2025 · publ. 10 October 2025 · source ↗
Sources
Generated September 26, 2026