Largest Health Insurance Companies

UnitedHealthcare, part of UnitedHealth Group, is the largest health insurance company based on revenue. UnitedHealthcare sells individual and family plans, as well as group plans, which you get through an employer.

UnitedHealthcare also has a network of more than 1.7 million doctors and healthcare professionals, with more than 7,000 hospitals. This means that if you have UnitedHealthcare, you will have many options for where you can get medical care.

You can buy individual and family plans from UnitedHealthcare in 30 states. UnitedHealthcare is headquartered in Eden Prairie, MN.

Kaiser Permanente is the second-largest provider of health insurance in the U.S. by revenue, with about $159 billion in revenue in 2025. However, Kaiser is the largest company by enrollment for group and individual health insurance. About 87% of its membership comes from group health insurance plans from employers.

Kaiser Permanente only sells policies in eight states and Washington, D.C., but coverage from the company is very popular where it's available. The insurance company's focus is on low-cost HMO plans that require you to use one of Kaiser's medical centers to get healthcare, unless it's an emergency. That can make medical care more seamless, as Kaiser operates both the medical offices and the insurance plans.

Centene is a large health insurance company, and most of its health insurance plans come from Ambetter. As a company, Centene is the third-largest major medical insurance company in the United States by revenue. It sells the most individual health insurance plans of any company, with 5,600,609 individual health plan members in 2025.

Ambetter is one of Centene's main individual health insurance companies. But Ambetter doesn't sell Medicare Advantage or Medicare Part D plans. Instead, Wellcare is the main Centene subsidiary selling these policies.

Centene was started in 1984 as a provider of Medicaid plans, and today, it's the largest provider of managed care Medicaid plans — where a health insurance company oversees Medicaid benefits — in the country.

Anthem, which is part of Elevance Health, is the fourth-largest medical insurance provider by revenue and has more than 5.2 million health insurance members. The company offers insurance to large and small businesses, individuals and families.

The company currently only sells plans in 14 states.

Anthem is part of the Blue Cross Blue Shield Association, which, in total, covers all 50 states and Washington, D.C. This can give you some benefits like nationwide access to medical care through the BlueCard program, which lets you use your coverage easily when you're traveling. The Blue Cross Blue Shield provider network is the largest in the country and includes about 85% of doctors and hospitals.

HCSC, which stands for Health Care Service Corp., is the fifth-largest health insurance company by revenue and enrollment, with more than 5 million customers. The company's name may not be familiar to most people, but HCSC is part of Blue Cross Blue Shield and runs companies in Illinois, Montana, New Mexico, Oklahoma and Texas.

In addition to managing health insurance companies, HCSC also works with local nonprofits in the communities it serves. HCSC provides funding to nonprofits that help improve nutrition, economic development, housing and more.

HCSC was founded in 1936. Today, the company also owns brands such as Dearborn Group, HealthSpring and Prime Therapeutics.

HCSC is just one of many Blue Cross Blue Shield companies. If you were to put all the subsidiaries together, BCBS would be the largest health insurance company in the country.