Top Five Largest Health Insurance Companies: Get to Know the Right Partner for Your Health Insurance

As of the information available in March 2021, the top five largest health insurance companies in the United States, based on membership, are:

1. UnitedHealthcare: The largest health insurer in the U.S.

2. Anthem (formerly WellPoint): One of the largest for-profit managed healthcare companies.

3. Centene Corporation: A major player in government-sponsored healthcare programs.

4. Humana: A leading health and well-being company with a focus on health insurance.

5. Cigna: A global health service company providing a range of health insurance products.

An image illustration of Top Five Largest Health Insurance Companies
Get to Know the Right Partner for Your Health Insurance

These companies collectively own a significant portion of the health insurance market in the United States, highlighting the concentration of the industry among a few major players.

It’s essential to note that rankings and market shares may have changed since the information available in March 2021.

United Healthcare

United Healthcare, an integral part of the UnitedHealth Group, claims its position as the largest health insurance company, actively providing an extensive array of health benefits.

This robust offering not only enables individuals to secure coverage at an affordable price but also streamlines the medical process and ensures access to high-quality treatment.

UnitedHealthcare Employer & Individual actively attends to the health needs of 26.7 million Americans, offering a comprehensive suite of consumer-oriented health benefit plans and services nationwide.

This commitment extends across various sectors, including large national employers, public sector employers, mid-sized employers, small businesses, and individual policyholders.

Devoted to enhancing the health and well-being of older adults and those eligible for Medicare, UnitedHealthcare Medicare & Retirement directs its services toward a substantial demographic of 13.2 million individuals.

Furthermore, UnitedHealthcare Global extends its influence globally, delivering medical and dental benefits to a significant population of 7.5 million people spread across more than 150 countries.

UnitedHealth Group, with a substantial workforce of approximately 168,000 employees operating in 21 countries, including Australia, Canada, China, India, the Philippines, Ireland, Italy, and the United Kingdom, comprehensively covers an expansive base of around 45 million individuals worldwide.

The extensive services provided by UnitedHealth Group span over 6,100 healthcare facilities and engage with 855,000 physicians and caregivers.

The operational headquarters of UnitedHealthcare is centrally located in Minnetonka, Minn.

Anthem, Inc. Health Insurance

Anthem, Inc., the second-largest managed health care company within the Blue Cross Blue Shield Association, actively serves an extensive demographic of 40 million health plan members.

In 2014, the corporate identity underwent a transition to Anthem, Inc., aligning with its unwavering dedication to serving fourteen U.S. states.

These states encompass California, Colorado, Connecticut, Georgia, Indiana, Kentucky, Maine, Missouri, Nevada, New Hampshire, New York, Ohio, Virginia, and Wisconsin.

Anthem’s affiliation with the Blue Cross Blue Shield Association provides policyholders with the advantageous access to medical care nationwide through the Blue Card program, engaging over 90% of physicians and hospitals in the largest provider network in the nation.

Aetna Health Insurance

Aetna, now under the umbrella of CVS Health Corp. since 2018, stands as a prominent provider of affordable insurance plans across a diverse range of coverage options.

With a substantial network that includes 22.1 million medical members, 12.7 million dental members, and 13.1 million pharmacy benefit management services members, Aetna’s outreach extends to over 690,000 primary care doctors and specialists, in addition to collaborating with over 5,700 hospitals.

Established in 1853, Aetna holds its position as the third-largest supplier of health insurance and services.

A considerable portion of its membership originate from group health insurance policies provided by employers.

Cigna Health Insurance

Cigna, the fourth-largest health insurance companies in the United States, operates globally from its headquarters in Bloomfield, Connecticut.

Beyond managing corporate health insurance policies and programs, Cigna actively provides dental, behavioral health, vision, supplementary health, and Medicare/Medicaid services.

Currently available in 16 states, including Arizona, Colorado, Florida, Georgia, Illinois, Indiana, Kansas, Mississippi, Missouri, North Carolina, Pennsylvania, South Carolina, Tennessee, Texas, Utah, and Virginia, Cigna has further expanded its coverage to offer Medicare Advantage plans in more than half of the nation.

Humana, Inc. Health Insurance

Humana, Inc., a distinguished health care provider founded in 1961 by David A. Jones, Sr., and Wendell Cherry, has evolved into a comprehensive insurance product and health and wellness services entity.

Originating as Extendicare, the company’s trajectory led it to become the largest nursing home company in the United States.

Organized into business segments such as Employer group, retail, and health and wellness services, Humana’s retail segment actively markets health insurance benefits directly to individuals, encompassing Medicare and commercial fully-insured medical and specialty health insurance benefits.

This comprehensive approach includes dental, vision, and other add-on health and financial security products.


1. What is health insurance?
Health insurance is a financial arrangement that covers the cost of medical expenses.

It provides individuals with financial protection against unexpected healthcare costs.

2. How do health insurance plans work?
Health insurance plans work by individuals paying regular premiums to the insurance company. In return, the insurer helps cover the costs of medical services and treatments based on the terms of the policy.

3. What is a premium?
A premium is the amount of money an individual pays to the health insurance company to maintain coverage. It is usually paid monthly, quarterly, or annually.

4. What is a deductible?
A deductible is the amount an individual must pay out of pocket for covered healthcare services before the insurance company starts contributing to the costs.

5. Can I choose my healthcare provider with health insurance?
It depends on the type of plan. Some health insurance plans have networks of preferred providers, while others allow you more flexibility in choosing healthcare providers.


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