Top 10 Health Insurance Companies in USA
Finding the right health insurance can feel like wandering through a maze: lots of names, different plan types, and confusing jargon. This guide explains the Top 10 Health Insurance Companies in the USA in plain language — who they are, what they’re best known for, and simple tips for choosing between them. The list below reflects market-share and enrollment trends from recent industry reports and public filings (sources at the end of the article). If you’re scanning for a plan, use this as a practical primer — not legal or medical advice — and check each company’s website or a licensed broker for plan details in your state.
How I chose these 10
I used widely reported market-share and enrollment data plus company filings and reputable health-policy analysis. These firms are the largest by covered lives, premiums, or program reach (Medicare Advantage, Medicaid, employer, and individual markets). The order here isn’t a strict “best-to-worst” ranking — it’s a curated top-10 list with plain descriptions to help you decide which companies to research more closely.
1. UnitedHealth Group
Why people know them: UnitedHealth Group (through UnitedHealthcare and Optum) is the largest U.S. health insurer by membership and revenue. They have wide reach across employer plans, Medicare Advantage, and individual markets. UnitedHealthcare is especially big in Medicare Advantage — a fast-growing segment for seniors.
What they offer: Employer health plans, Medicare Advantage and Part D plans, Medicaid products (in some states through partners), and an extensive pharmacy/health services arm (Optum) that offers care management and telehealth.
Good fit if: You want broad national provider networks, lots of plan options (especially for Medicare Advantage), and integrated pharmacy/health services.
Watch out for: Plan networks and prior authorization rules vary by plan and county. In recent years UnitedHealthcare has adjusted its plan choices in some markets; always check local provider networks and 2026 plan availability.
2. Elevance Health (Anthem)
Why people know them: Elevance Health is the parent company for what many still call Anthem (and several regional Blue plans). It’s consistently among the largest carriers by membership and revenue, offering a mix of employer, individual, Medicaid, and Medicare products.
What they offer: Large-group and small-group employer plans, Affordable Care Act (ACA) marketplace plans in participating states, Medicare Advantage, and Medicaid managed-care programs.
Good fit if: You live where Elevance’s brands are strong — many states have their own regional presence — and you want the familiarity of a large national carrier with strong employer relationships.
Watch out for: Plan availability and provider networks vary by state; check local reviews for customer service and claims handling.
3. CVS Health (Aetna)
Why people know them: CVS Health acquired Aetna and now combines pharmacy (CVS/pharmacy and Caremark) with health plans. Aetna remains a major national insurer, especially for employer-provided coverage and Medicare Advantage. This vertical integration (insurer + pharmacy + care services) is a defining feature.
What they offer: Employer plans, Medicare Advantage and Part D, Medicare Supplement, and strong pharmacy benefits. They also offer care coordination and retail-based health services through CVS clinics.
Good fit if: You value integrated pharmacy programs, or you want a carrier with many retail clinic touchpoints and a strong pharmacy benefit manager (PBM).
Watch out for: Vertical integration can mean complex pricing for some services; read the drug-pricing and formulary details carefully.
4. Centene Corporation
Why people know them: Centene is a big player in Medicaid managed care and also sells Marketplace (ACA) plans through brands like Ambetter. Centene focuses heavily on government programs (Medicaid, CHIP) and lower-income populations.
What they offer: Medicaid managed care in many states, Marketplace plans, specialty services for behavioral health and long-term supports, and some Medicare Advantage products.
Good fit if: You’re on Medicaid or qualify for Marketplace plans and want a carrier with deep experience in public programs.
Watch out for: State-by-state performance varies; local provider relationships and customer service can differ widely.
5. Humana
Why people know them: Humana is well-known for Medicare Advantage and individual senior-focused programs. They also offer employer group plans and specialty care programs. Humana has been a leader in the Medicare space for years.
What they offer: Medicare Advantage and Part D plans, Medicare Supplement, employer group plans, and programs aimed at chronic condition management and home-based care services.
Good fit if: You’re shopping Medicare Advantage plans and want options focused on seniors’ needs, disease management, or home health services.
Watch out for: As with other large carriers, network breadth and supplemental benefits vary by plan and county — compare star ratings and member reviews.
6. Kaiser Permanente
Why people know them: Kaiser Permanente operates an integrated care model: they run hospitals, clinics, and the insurance plan itself. That single-system setup can make care more coordinated in places where Kaiser operates (not nationwide — Kaiser is regional, strongest in California and parts of the West, Mid-Atlantic, and Colorado).
What they offer: HMO-style plans where Kaiser physicians, facilities, and insurance work together. They excel at preventive care, integrated electronic medical records, and in-system coordination.
Good fit if: You live in a Kaiser service area and want tight coordination between doctors, hospitals, and insurance — often results in smoother care navigation and strong preventive services.
Watch out for: Kaiser’s model is “closed network” — if your preferred doctor or hospital is outside Kaiser, you’ll likely need to switch providers or pay out-of-network costs.
7. Blue Cross Blue Shield Association
Why people know them: “Blue Cross Blue Shield” isn’t a single company but an association of independent, locally licensed companies that operate under the BCBS name in different states. BCBS plans together cover tens of millions nationwide and are common in employer and individual markets.
What they offer: State or regional BCBS plans provide employer, individual, Medicare, and Medicaid products. Because BCBS entities are local, their plan choices and networks reflect regional markets.
Good fit if: You want a familiar, locally regulated brand with solid provider networks in many states.
Watch out for: Since BCBS is a federation of different companies, customer experience and plan rules can vary dramatically across states.
8. Molina Healthcare
Why people know them: Molina focuses mainly on Medicaid and Medicare, especially in lower-income communities and states with significant managed-medicaid enrollment. They are a major provider of public program plans.
What they offer: Medicaid managed care, Medicare Advantage in some markets, and Marketplace plans where they operate.
Good fit if: You are eligible for Medicaid or low-cost Marketplace coverage and want a carrier experienced with public program administration.
Watch out for: Local provider access and administrative responsiveness can vary; check state-level reports for quality and grievance timelines.
9. Health Care Service Corporation (HCSC)
Why people know them: HCSC (often known by Blue Cross Blue Shield names in many Midwestern states) is one of the largest customer-owned health insurers in the U.S. They’re big in Illinois, Montana, New Mexico, Oklahoma, and Texas.
What they offer: Employer and individual plans, Medicare products, and regional provider networks.
Good fit if: You live in HCSC’s footprint and want a large regional carrier with strong local provider relationships.
Watch out for: As with most regional plans, check network directories and member satisfaction scores in your state.
10. Centene (Ambetter) — note: Centene listed earlier
Why people know them: (Centene is already on this list; for the tenth spot I’ll highlight another widely known insurer often in top-10 lists:) Note: To keep this as a true “top-10,” you may see slight variations between lists — companies like Cigna and Devoted Health sometimes appear depending on the metric (revenue vs. enrolled lives). For this slot, a frequently listed national firm is Cigna.
Cigna is a large global health-services company that serves employer groups, Medicare, and international markets; it’s recognized for broad employer networks and global travel health services.
What they offer: Employer-sponsored plans, Medicare Advantage and supplemental products (through Evernorth & local entities), and international health coverage.
Good fit if: Your employer offers Cigna, or you need global coverage or strong national provider access.
Watch out for: Plan details can look different across employer-sponsored versus individual-market offerings — always read the benefits summary.
Quick consumer tips — how to compare these big carriers
- Network matters. A cheap premium won’t help if your doctor isn’t in-network. Confirm your PCP and local hospitals are covered.
- Plan type = experience. HMOs limit out-of-network care but keep costs predictable. PPOs are pricier but more flexible. Medicare Advantage plans often include extras (hearing, vision) but can have prior authorization rules.
- Look beyond premiums. Check deductibles, out-of-pocket maximums, copays, and prescription drug formularies — especially if you take regular meds.
- Read provider directories carefully. They change. Call your doctor’s office to confirm they accept the exact plan and network.
- Check quality ratings. For Medicare Advantage, CMS star ratings are useful. For general service and complaints, state insurance departments and consumer reviews help.
- Use a broker for help. Licensed brokers can show multiple carriers and explain tradeoffs at no extra cost to you (they’re usually paid by insurers).
Industry trends worth knowing
- Medicare Advantage concentration: A few large firms (UnitedHealthcare and Humana, among others) account for a large share of MA enrollment; this impacts choice and plan design in many areas.
- Market adjustments & county exits: Insurers occasionally reduce plans in certain counties when costs or reimbursement rules change. That means plan availability can shift between open-enrollment periods — always re-check yearly options.
- Integration with pharmacy & services: Major players now combine insurance, PBMs, and care-delivery arms (examples: CVS/Aetna; UnitedHealth/Optum). That can yield conveniences (streamlined care, integrated digital tools) — but also complex pricing rules.
Final practical checklist (two-minute action plan)
- Gather: a list of current doctors, medicines, and preferred hospitals.
- Use: carrier websites or your employer portal to compare plans (look for the plan summary and provider search).
- Compare: monthly premium + expected annual out-of-pocket based on your usual care.
- Confirm: your primary doctor accepts the plan.
- Ask: a licensed broker or your state health insurance assistance program (SHIP) if you’re on Medicare.
Sources and further reading (key references)
- National Association of Insurance Commissioners / market-share summaries as compiled in recent roundups (overview of top insurers by market share).
- UnitedHealth Group 2024 filings and Form 10-K (financials, Medicare Part D and Medicare Advantage enrollment).
- Kaiser Family Foundation analysis and Medicare Advantage enrollment trends (breakdowns by carrier and national share).
- Elevance Health (Anthem) 2024/2025 impact and membership reports (company enrollment and business lines).
- Reuters reporting on insurers’ plan changes and county/market withdrawals (recent examples of plan exits and what that means for members).