The latest market share data from the National Association of Insurance Commissioners (NAIC) shows that the 10 largest accident and health insurance companies in the US account for almost 60 percent of the market. These companies wrote about $995 billion in direct premiums.
In this article, Insurance Business looks closely at the largest health insurance companies in the US. We will crunch the numbers and outline the types of coverage they bring to brokers, employers, and policyholders. This helps readers compare the best health insurance companies based on scale, products, and focus.
According to NAIC's latest market share report, the US health insurance market remains dominated by the largest health insurance companies. Accident and health insurers wrote about $1.7 trillion in direct earned premium in 2024, almost double the roughly $713 billion in premiums written a decade earlier. This shows how health plans and medical insurance have expanded to cover care, prescription drugs, and other health costs for more than 270 million people across all 50 states.
In this list of the top 10 health insurance companies in the US, Insurance Business profiles the leading groups by direct written premiums (DWP), using NAIC's data. These insurers range from national brands and affiliated carriers to diversified health and benefits writers serving tens of millions of members.
For each carrier, the article outlines what the company offers, and what brokers and employers should know about product mix and customer satisfaction trends. The leading health insurance groups, according to the latest data are:
UnitedHealth Group boasts of a strong network of over 1.5 million medical and healthcare specialists and 6,200 hospitals. These professionals provide medical and dental benefits to the insurer's more than 49 million members across the country. Here's a breakdown of the group's membership:
| UNITEDHEALTH MEMBERSHIPS IN THE US |
|---|
| 27.1 million individual and employer health benefits plan members |
| 13.6 million Medicare and retirement plan members |
| 8.4 million community and state benefits plan members |
UnitedHealth policies are available nationwide. The health insurance giant delivers benefits and services through its two business units:
UnitedHealthcare is the company's health insurance unit offering members a range of healthcare services and coverage. These include:
Optum is UnitedHealth's technology arm offering information and tech-enabled services through three platforms:
CVS is a diversified healthcare benefits company. It brings together Aetna's health insurance business, a large pharmacy chain, and a major pharmacy benefits manager under one brand.
CVS writes health policies across all 50 states, combining traditional medical insurance with pharmacy and care‑delivery services. CVS Health's scale goes well beyond its core insured book:
CVS also operates a pharmacy benefit manager with about 100 million plan members, tying drug benefits to its health plans and employer contracts. A senior pharmacy‑care arm serves over one million patients each year. This integrated model means CVS often controls both the medical risk and the pharmacy spend for large employer groups and government programs.
Based in St. Louis, Centene Corporation is one of the best health insurance companies in the US and ranks as 23rd on the 2025 Fortune 500. It is the country's largest:
The company's health plans reach across all 50 states, with products available to more than one-in-15 individuals across the nation. These include Medicaid and Medicare members, and individuals and families served by the Health Insurance Marketplace.
As of late 2024, Centene listed 28.6 million members in total, comprised of:
The company has Medicaid deals with 31 states, and almost three-fifths of its premiums and services revenue came from Medicaid last year.
Centene has recently faced some legal challenges and financial headwinds, but the company has kept its community programs running. Health Net, a Medi-Cal managed care health plan in California. The Centene Foundation announced a joint investment exceeding $7.2 million to expand health care services for underserved populations through mobile health clinics.
Humana focuses almost entirely on government-backed programs, with about 93 percent of its premiums and services revenue coming from Medicare and other government health plans. This company operates through two main segments: Insurance and CenterWell.
Humana's insurance segment covers:
Meanwhile, CenterWell runs primary care clinics, home health care, and pharmacy services. As of late 2025, the company served roughly 15 million members in medical benefit plans, plus 4.7 million in specialty products.
Humana offers Medicare Advantage health plans in 46 states and Washington, D.C., covering 85 percent of US counties. It is the second-largest for-profit Medicare Advantage provider among US insurers, holding a 17 percent market share of total Medicare Advantage enrollment in 2025. Together with UnitedHealth Group, the two companies account for nearly 46 percent of all Medicare Advantage enrollees nationwide.
Humana also offers stand-alone prescription drugs plans and is one of the largest PDP providers in the country. The company is preparing to expand its integrated dual-eligible programs in Michigan, Illinois, and South Carolina in early 2026. Despite financial challenges, Humana's Medicaid footprint now spans 13 states, with Georgia and Texas expected to launch in 2027.
With UnitedHealthcare expected to shed more than 1.1 million Medicare Advantage members in 2026, Humana may become the top health insurance provider by Medicare Advantage membership by year's end.
Headquartered in Indianapolis, Indiana, Elevance Health Group is the largest for-profit managed health care company in the Blue Cross Blue Shield Association, formerly known as Anthem, before rebranding in June 2022. Elevance operates through four segments:
The Health Benefits segment covers a broad range of health plans, which include commercial, Medicare Advantage, Medicaid, and the Federal Employee Program. The company offers its Blue Cross Blue Shield-branded health plans under the Anthem name in 14 states.
Carelon, its health services arm, serves one-in-three Americans through partnerships with health plans, government agencies, and health care providers.
Its CarelonRx segment manages prescription drugs and pharmacy benefits, while Carelon Services focuses on virtual care for complex Medicaid and Medicare patients. This digital capability was expanded via the acquisition of CareBridge in late 2024.
Members on Anthem health plans can also access virtual care visits, including video consultations through the Sydney Health app, at no cost on most plans. As of December 31, 2025, Elevance served approximately 45.2 million members across its affiliated health plans.
Better known as Kaiser Permanente, Kaiser Foundation Group is an integrated managed care consortium headquartered in Oakland, California. It is one of the largest non-profit insurance companies in the US and the biggest managed care organization in the country.
Kaiser Foundation Group operates through three interdependent entities:
Unlike the other best health insurance companies in our list, Kaiser owns its hospitals and employs its own physicians.
Kaiser companies offer a wide range of health plans, covering individuals, families, groups, Medicare Advantage, Medicaid, and the Federal Employees Health Benefits Program. Most plans are HMO-based, requiring members to use Kaiser's network of 618 medical offices and 40 hospitals, with a primary care doctor for specialist referrals.
Unlike most major insurance companies, Kaiser does not operate across 50 states. Its health plans are only available in nine states and the District of Columbia, where it serves 12.6 million members.
In terms of quality, Kaiser Permanente's Medicare Advantage health plans earned either 4 or 4.5 stars in the CMS 2025 Star Ratings. As regards customer satisfaction, Kaiser ranks highest in overall customer satisfaction with Medicare Advantage plans in California for a second consecutive year, with a score of 675.
In June 2025, Fitch Ratings also affirmed an Insurer Financial Strength rating of AA (stable) for Kaiser Foundation Health Plan and its insurance company subsidiaries. However, member experience ratings, including customer service and access to health care, remain below most major providers.
Health Care Service Corporation (HCSC) is a Mutual Legal Reserve Company and the largest customer-owned health insurer in the US. Formerly known as Hospital Service Corporation, the company changed its name to Health Care Service Corporation in 1975. It is based in Chicago, Illinois and has a network of offices across the country.
As a Mutual Legal Reserve Company, HCSC is an independent licensee of the Blue Cross Blue Shield Association. It is the Blue Cross Blue Shield licensee for five states:
HCSC provides coverage options for employers, individuals, and families, and Medicare and Medicaid plans. It also offers related health care products and services such as pharmacy solutions, life and dental insurance, and health technology through a network of affiliates and subsidiaries. HCSC offers a range of health insurance plans across four metal tiers: Bronze, Silver, Gold, and Platinum.
Cigna Health Group operates as a commercial medical carrier closely tied to one of the largest pharmacy benefits and specialty‑care platforms. Cigna Health Group sits within The Cigna Group, a global health company that now runs on two main platforms: Evernorth Health Services and Cigna Healthcare.
Cigna rebranded its holding company as The Cigna Group in 2023. It renamed its benefits arm Cigna Healthcare and its services arm Evernorth Health Services. Evernorth brings together Express Scripts, Accredo and eviCore under one health‑services brand.
Cigna's Evernorth Health Services is a major pharmacy benefit and specialty‑care platform. It includes pharmacy benefit services plus "Specialty and Care Services," providing integrated solutions around specialty drugs, home delivery, care management and virtual care. Specialty and care services have been a key driver of recent earnings growth for this carrier.
Cigna Healthcare focuses on commercial medical coverage for employers and individuals, with a growing stop‑loss business. The group is shifting away from public‑program risk: it agreed to sell its Medicare Advantage, Medicare Part D, supplemental benefits and CareAllies businesses to HCSC in a transaction valued at about $3.7 billion. The deal was closed in March 2025.
Molina Healthcare Inc. is a managed care company headquartered in Long Beach, California. It was founded in 1980 by emergency room physician C. David Molina, who wanted to give better health care to patients who could not get it elsewhere.
As a Fortune 500 company, it provides managed health care services under the Medicaid and Medicare programs and through the state insurance marketplaces.
Molina does not offer commercial employer-sponsored health plans or medical insurance products beyond government programs. Compared to the larger insurance companies, it only operates in 15 states and Puerto Rico, with continued growth in the dual-eligible Medicare and Medicaid market. As of the third quarter of 2025, the company has served approximately 5.6 million members.
The company offers a focused range of government-sponsored health plans, including Medicaid, CHIP, ACA Marketplace plans, and Medicare Advantage. Most plans are HMO-based. The company offers Medicare Advantage plans with $0 premium HMO plans and prescription drug coverage, which is included in most Medicare Advantage plans.
Molina Healthcare also offers Teladoc, a free virtual care service to its members accessible by phone, video, or mobile app, with no appointment needed. Whenever necessary, Teladoc doctors can send a prescription to a local pharmacy, and members can use Teladoc for general medical and behavioral health services.
GuideWell Mutual Holding Corporation is a not-for-profit, policyholder-owned health solutions holding company based in Jacksonville, Florida. GuideWell was created in 2013 by a reorganization initiated by Florida Blue, a member company of the Blue Cross Blue Shield Association. The majority of its health plans are offered in Florida and Puerto Rico.
In June 2025, GuideWell made its Fortune 500 debut, ranking 136th with $32.955 billion in 2024 revenue. Under outgoing CEO Pat Geraghty, who retired December 31, 2025, the enterprise grew from an $8 billion health insurance company into a $32 billion health solutions company.
GuideWell is the parent to a family of health care and medical insurance companies, including:
GuideWell is also a partial owner of Prime Therapeutics LLC, the pharmacy benefits manager owned and operated by 19 Blue affiliates, which help manage prescription drug coverage for members. AllianceRx Walgreens Prime, the pharmacy benefits manager's specialty pharmacy partnership with Walgreen Co., handles much of its specialty prescription drug contracting.
Florida Blue is the state's Blue Cross Blue Shield licensee and one of the best health insurance companies in the state. It offers ACA health plans, Medicare, employer coverage, and in-person help through Florida Blue Centers. As a not-for-profit organization, it focuses on community health, and broad access to providers, remaining a common choice for individuals and families needing ACA Marketplace coverage.
Find out how health insurance works in the US, as well as in the different regions we cover in this comprehensive guide to health insurance.
Here are the typical features of the four most common health insurance plans in the US:
Each plan type has distinct advantages and disadvantages, making the choice dependent on individual preferences and priorities. These include provider flexibility, cost considerations, and preferred healthcare networks.
Prioritize these factors but choose coverage from the best health insurance companies with your client's needs and budget in mind. Finding the optimal combination of cost and good coverage is crucial, especially in the next few years as health insurance costs increase.
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