UnitedHealth Group continues to be the largest health insurer in the U.S., with nearly 45 million members in 2025, according to the Peterson-KFF health system tracker.
The data is from Mark Farrah Associates and includes enrollment across the individual market, fully insured and self-funded group plans, Medicaid managed care and fee-for-service programs, and Medicare Advantage, totaling about 320 million enrollments.
Top 10 largest insurers by enrollment in 2025:
- UnitedHealth Group: 44.8 million members
- Elevance Health: 36.1 million
- CVS Health: 24.9 million
- Centene: 19 million
- Health Care Service Corp: 18.7 million
- Cigna Healthcare: 16.2 million
- Kaiser Permanente: 12.3 million
- Humana: 7.5 million
- GuideWell: 6.1 million
- BCBS Michigan: 4.9 million
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