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Largest Health Insurance Companies for 2024

The five largest health insurance companies by revenue are UnitedHealth Group, Anthem, Kaiser Permanente, Ambetter and Humana.

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5 largest health insurance companies

What are the biggest health insurance companies?

These five most popular companies make up 50% of health insurance enrollment.

Market share of largest health insurance companies

Largest health insurance companies by revenue

Market share
Revenue (billions)
UnitedHealth Group15%$189
Elevance Health (Anthem)10%$124
Kaiser Permanente9%$114
Centene (Ambetter)9%$110
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Top 5 largest health insurance companies

Each of the largest health insurance companies has millions of customers. You can enroll in a health insurance policy from one of the largest companies in many different ways. For example, your employer’s benefit plan may offer health insurance, or you can buy a private insurance plan through the Affordable Care Act (ACA) marketplace, also called "Obamacare."

1. UnitedHealth Group

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About UnitedHealth Group

UnitedHealthcare, part of UnitedHealth Group, is the largest health insurance company based on revenue. UnitedHealthcare offers a variety of products from individual health insurance to employer plans for some of the biggest corporations.

You can buy policies directly from UnitedHealthcare in all 50 states, and individual and family plans on the health insurance exchanges are available in about half the states. UnitedHealthcare is headquartered in Minnetonka, MN.

UnitedHealthcare also has a network of over 1.3 million doctors and health care professionals, with more than 6,500 hospitals. This means that if you have UnitedHealthcare, you will have many options for where you can get medical care.

2. Anthem

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About Anthem

Anthem is the second-largest medical insurance provider by revenue and has nearly 6 million health insurance members. The company offers insurance to large and small businesses, individuals and Medicaid and Medicare markets.

The company currently only sells plans in 14 states — California, Colorado, Connecticut, Georgia, Indiana, Kentucky, Maine, Missouri, Nevada, New Hampshire, New York, Ohio, Virginia and Wisconsin.

Anthem is part of the Blue Cross Blue Shield Association, which, in total, covers all 50 states. This can give some customers benefits such as nationwide access to medical care through the BlueCard program. The Blue Cross Blue Shield provider network is the largest in the country and includes about 90% of doctors and hospitals.

3. Kaiser Permanente

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About Kaiser Permanente

Kaiser Permanente is the third-largest provider of health insurance in the U.S. by revenue. Much of its membership comes from group health insurance plans from employers. But it also sells low-cost plans across a variety of coverage types including individual health insurance, Medicare Advantage and Medicaid.

Kaiser Permanente only operates in eight states and the District of Columbia. However, it's very popular in the states where it is available. The insurance company's focus is on low-cost HMO plans where you'll usually have to use one of Kaiser's medical centers for your health care to be covered.

4. Ambetter

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About Ambetter

Ambetter, and its parent company Centene, make up the fourth-largest major medical insurance company in the United States by revenue. Headquartered in St. Louis, Centene is a publicly traded company that's No. 25 on the Fortune 500.

Ambetter is one of Centene's main subsidiaries selling individual health insurance. 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 in the country.

5. Humana

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About Humana

Humana is the fifth-largest health insurance company by revenue. The company was founded in 1961 and originally sold long-term care insurance before expanding into selling health insurance policies.

Humana focuses on employer health insurance plans, dental and vision insurance, and Medicare plans including Medicare Advantage, supplemental and prescription plans. Humana has not offered new individual ACA health insurance since January 2018.

Largest major medical insurance provider by state

Blue Cross Blue Shield is the largest health insurance company in most states by membership. That includes affiliates like Anthem.

You can buy individual health insurance policies through the health insurance marketplace if you currently do not have health insurance through an employer or a federally funded program like Medicaid or Medicare. For the 2023 plan year, 16.3 million people enrolled in plans through the health insurance marketplace.

AlabamaBlue Cross Blue Shield of Alabama
AlaskaPremera Blue Cross
ArizonaBlue Cross Blue Shield of Arizona
ArkansasArkansas BlueCross BlueShield
CaliforniaKaiser Permanente
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Health insurance company rankings by enrollment

Kaiser Permanente is the largest health insurance company by enrollment, with nearly 9 million members with an individual or group health insurance plan. Even though Kaiser's plans are only sold in eight states and Washington, D.C., it has high enrollment in the states where it is available.

However, Kaiser Permanente is not the highest-revenue company because it sells cheap health insurance plans, including low-cost HMO (health maintenance organization) plans. Anthem has the second-largest membership, followed by UnitedHealthcare.

Kaiser Permanente8.9 million
Elevance Health (Anthem)5.8 million
UnitedHealth Group4.7 million
HCSC (Blue Cross)4.4 million
Centene (Ambetter)4.0 million
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Individual and employer health insurance plans

Blue Cross Blue Shield (BCBS) operates as many independent companies that are a part of the Blue Cross Blue Shield Association. Of these 10 health insurance companies with the most members, five are affiliates of the Blue Cross Blue Shield Association. If all BCBS affiliates were combined, they would have the largest health insurance enrollment in the U.S.

Frequently asked questions

What are the top five largest health insurance companies?

The five largest health insurance companies by revenue are UnitedHealth Group, Anthem, Kaiser Permanente, Centene and Humana. They make up about half of the total market share in the health insurance industry. UnitedHealthcare has the highest revenue, earning $189 billion, but Kaiser Permanente has the largest enrollment with nearly 9 million members.

How should you compare health insurance companies?

Start by looking at the best health insurance companies, which provide high-quality coverage and have satisfied customers. Next, consider how much a plan costs based on the level of coverage you need. Also, look at which company gives you access to the doctors and hospitals you prefer.

Should you choose a large health insurance company when buying a plan?

The biggest health insurance companies usually have a wide network of doctors and medical providers. This can give you more options for where you get your medical care, and you may also have better coverage when traveling. However, poor customer service is a common complaint about big insurance companies, and there are several smaller companies that have better customer satisfaction.


Data on market share, revenue and enrollment is from S&P Capital IQ, pulled in September 2023 based on the most recent annual data available — for the calendar year of 2022. Enrollment data includes group and individual health insurance plans, but not Medicare or Medicaid. National enrollment and California enrollment are reported separately but have been combined.

Editorial Note: The content of this article is based on the author's opinions and recommendations alone. It has not been previewed, commissioned or otherwise endorsed by any of our network partners.