Health Insurance

Largest Health Insurance Companies of 2021

Largest Health Insurance Companies of 2021

In the United States, there are currently more than 900 health insurance companies that offer medical coverage.

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However, the health insurance industry is dominated by five companies. In order, the top health insurers by market share are Anthem, Centene, UnitedHealthcare, Humana and Health Care Service Corp. (HCSC), and together they control nearly 44% of the market.

All of these providers offer basic health insurance products to individuals and companies, along with other services that include Medicaid and Medicare policies, long-term care insurance, dental insurance and vision benefits.

What are the biggest health insurance companies?

The biggest health insurance companies in the United States include well-known insurance providers. Many of these companies offer similar products, but some tend to specialize in additional products such as Medicaid and Medicare. Below, we break down the largest health insurers by market share, by membership, by revenue and by state.

Market share of largest health insurance companies

Top 5 largest health insurance companies by membership

The largest health insurance provider can be defined as the company that has the highest number of members. Also known as covered lives, membership means the number of individuals who have enrolled in a health insurance plan with that provider. You can enroll in a health insurance policy in many different ways. For example, your employer’s benefit plan may offer health insurance coverage. Other ways include:

  • Medicare and retirement plans
  • Medicaid services
  • Individual health insurance (through open enrollment)

1. UnitedHealthcare


70 million members

UnitedHealthcare is the largest health insurance company by total covered lives. The provider offers a variety of products from individual health insurance to full employer benefits plans for some of the biggest corporations. Furthermore, its policies can be purchased in all 50 states. UnitedHealthcare is headquartered in Minnetonka, Minn.

Along with having the most members, UnitedHealthcare also has a care network of over 1.3 million physicians and health care professionals with more than 6,000 hospitals. This means that if you have UnitedHealthcare, you will have many options to choose from to receive care.

2. Anthem


39.9 million members

Anthem is the second-largest medical insurance provider by total members, with almost 40 million lives covered. The company's Commercial and Business health care segment offers network-based care to large and small businesses, individuals and Medicaid and Medicare markets.

Anthem is a licensee of the Blue Cross Blue Shield Association. This means that typically, when searching for Anthem policies on your state marketplace exchange, you will find that its products will be titled BCBS followed by the name of your state, but the insurer you will be buying from will be Anthem.

The company currently operates in California, Colorado, Connecticut, Georgia, Indiana, Kentucky, Maine, Missouri, Nevada, New Hampshire, New York, Ohio, Virginia and Wisconsin.

3. Aetna


22.1 million members

Aetna was acquired by CVS Health Corp. in 2018. CVS Health now operates the company and has been able to seamlessly integrate its provider networks with Aetna's membership base. Founded in 1853, Aetna is the third-largest provider of health insurance and services by membership. However, most of its membership comes from providing health insurance to employers and their employees in the private market. Since 2015, Aetna has removed itself from all Affordable Care Act marketplaces due to a loss in revenue.

4. Cigna


20.4 million members

Cigna is the fourth-largest major medical insurance company in the United States by membership. Headquartered in Bloomfield, Conn., Cigna offers health insurance and health services to companies throughout the world. In addition to corporate health insurance policies and management of those plans, Cigna also offers dental, behavioral health, vision, supplemental health and Medicare/Medicaid retirement benefits.

Cigna currently offers individual health insurance in 11 states: Arizona, California, Colorado, Florida, Georgia, Maryland, Missouri, North Carolina, South Carolina and Tennessee.

5. Humana


16.6 million members

Humana comes in as the fifth-largest health insurance company by membership. The provider was founded in 1961 and originally sold long-term care insurance before expanding into selling health insurance policies. However, in 2017 the company announced that it would no longer be offering individual health insurance in the 11 states where it had previously provided plans. If you still have a policy from Humana, then it will still honor the responsibilities of offering coverage benefits through your plan.

Largest major medical insurance provider by state

In 2020, nearly 11.5 million people purchased a health insurance policy through a state marketplace. Also known as individual health insurance, these policies can be purchased if you currently do not receive health care through an employer or a federally funded program like Medicaid or Medicare. Below is the biggest health insurance provider in each state.

AlabamaBlue Cross Blue Shield of Alabama
AlaskaPremera Blue Cross
ArizonaCentene Corp.
ArkansasArkansas Blue Cross Blue Shield
CaliforniaBlue Shield of California
ColoradoKaiser Foundation
District of ColumbiaCareFirst
GeorgiaCentene Corp.
HawaiiHawaii Medical Service Association
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Health insurance company rankings by revenue

Along with membership, the size of a health insurance company can be broken down by the amount of revenue it generates. Revenue is created in a health insurance company by the premiums it charges, the number of policies it writes, the services it sells and the number of businesses it operates in.

Based on our analysis, UnitedHealthcare is the largest health insurance company by revenue, with total revenue topping $257 billion during 2020. This makes the insurer the largest company both by covered lives and by revenue. Interestingly, although Anthem is the largest health care company by market share and the second-largest by membership, it is only the third-largest by revenue.

1UnitedHealthcare$257 billion
2Anthem$122 billion
3Centene$111 billion
4Kaiser Permanente$89 billion
5Humana$77 billion
6CVS Health$75 billion
7HCSC$47 billion
8Molina Healthcare$19 billion

Frequently asked questions

How should one determine the largest health insurance companies?

When determining what the biggest health insurance companies are, there are a variety of variables to analyze. Market share, for example, analyzes the portion of the industry that the company controls and therefore shows the company's reach among policyholders. Furthermore, market share is closely related to total membership, which shows the number of individuals that the company currently covers with health insurance. Finally, you can analyze revenue, which is a measure of how much money that company brings in annually.

What are the top five largest health insurance companies?

The largest health insurance companies include Anthem, Centene, UnitedHealthcare, Humana and Health Care Service Corp. (HCSC). These five companies represent nearly 44% of the total market share in the health insurance industry. Anthem is the largest health insurer by market share. However, UnitedHealthcare is the largest by membership and by revenue, with total revenue of over $257 billion in 2020.

How should one compare health insurance companies?

Comparing health insurance companies is crucial when shopping for a health insurance policy. Outside of premiums, deductibles and the plan network, companies can have a variety of differences. For example, some health providers offer extra benefits if you become a policyholder, such as gym memberships or discounts on health programs. These should not be the No. 1 reason you choose a company but are important to consider in the shopping process.


Market share data for 2020 was pulled using the S&P Market Intelligence Platform market share tool. Revenue figures for 2020 were found using the same analysis as well as looking at annual 10K's filed by the individual health insurance companies.

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