Want to know which health insurance companies dominate the U.S. healthcare landscape? We have the latest list! The United States is known for many of its industries, including a massive health and medical insurance sector, which is valued at $1.59 trillion as of this year (2025). The best part? The market is growing steadily each year at a CAGR of over 6% and is expected to reach $2.13 trillion by 2030.
So, who are the key players and why should you know about them? The answer is simple! These health insurers directly impact your reimbursement opportunities. Therefore, prioritize enrolling in the top networks and expand your patient base. Let’s get to know the leading health insurance companies in the USA today.
Top 10 Health Insurance Companies in the USA by Market Share
So, who are the largest health insurance companies in the U.S.? Before giving you their names, let’s briefly discuss how we selected each of them. The answer is quite literally mentioned in the heading; we chose the top 10 names based on their market share.
To be honest, the National Association of Insurance Commissioners (NAIC’s) most recent market share reports were quite helpful in this regard. Our team analyzed these companies and their total direct written premiums across all health segments. Below is a list of the 10 largest medical insurance companies in descending order.
1. UnitedHealth Group
UnitedHealth Group once again holds the top position. This American healthcare and well-being company has two primary goals: to help people live healthier lives and improve healthcare systems. Therefore, it offers a wide range of health solutions through its two primary divisions, UnitedHealthcare and Optum.
UnitedHealthcare is the insurance division of this company. In fact, it is one of the largest health insurance companies in the USA., providing an array of health benefit plans to people of all ages and budgets. With a network of 1.7 million healthcare providers and over 7,000 facilities, it serves millions of people in the U.S.
UnitedHealth Group controls over 16% of the market and has approximately $269.45 billion in direct written premiums. Therefore, you should definitely get credentialed with UnitedHealthcare.
2. CVS Health (including Aetna Health)
There has been a major change in CVS Health’s ranking. The company has climbed from fifth to second place in NAIC’s latest report with a market share of 7.22%. As we have seen, the healthcare industry has undergone significant changes in the past few years. This includes a series of mergers and acquisitions.
CVS Health acquired Aetna in 2018, which transformed this retail pharmacy chain into a healthcare giant. As one of the leading health insurance companies, it offers advanced care solutions, such as pharmacy services and health plans. Moreover, it serves over 36 million people through Aetna.
In short, CVS Health is now the second-largest health insurance payer, right behind UnitedHealthcare, with $121.24 billion worth of policies written in 2024. Interested in joining this network? You can refer to our comprehensive Aetna provider credentialing guide.
3. Centene Corporation
Centene is the third-largest health insurance company in the U.S. According to NAIC, it holds a 6.74% market share and received nearly $113.19 billion by issuing policies in 2024. Founded in 1984, this St. Louis-based private healthcare company manages both government and commercial insurance plans. It also sells marketplace insurance products through Ambetter.
One interesting fact about Centene? It started as a nonprofit Medicaid plan in Milwaukee. However, it now offers healthcare products and solutions to more than 1 individual among 15 people. Centene is one of the top-rated health insurance companies. Hence, over 28 million people rely on its services. Out of these numbers, 13 million are Medicaid members.
It is, in fact, the largest Medicaid managed care organization in the country, serving a vast number of low-income individuals, children, and women. Therefore, if your primary patient base is the low-income population, you should complete Centene/Ambetter credentialing as soon as possible.
4. Humana
You should also consider enrolling in Humana’s network. With a market share of 6.59%, it is currently the fourth-largest health insurer in the U.S. Established in 1961, it is one of the top private health insurance companies and is committed to supporting and improving communities at a local level.
Hence, it offers personalized health insurance for individuals, families, and employers, including dental and vision insurance. Humana also offers a wide range of Medicare and Medicaid plans, and has over 14.8 million medical members. Plus, it collected over $110.55 billion in premium income in 2024, making it one of the biggest health insurance companies.
In short, it is quite beneficial to become a Humana-credentialed provider, especially if you wish to improve your financial position.
5. Elevance Health Inc.
Previously known as Anthem, Elevance Health is the 5th name on our list of the top 10 health insurance companies. Its new name mirrors its mission of elevating whole health and advancing it beyond traditional healthcare. Hence, this private insurance firm partners with over 104,000 associates to support numerous people across their entire health journey.
Elevance Health is known for its comprehensive suite of commercial, Medicare, and Medicaid plans. But we aren’t here to discuss these plans. What benefits does it bring to the providers? Based on its direct written premiums in 2024, Elevance Health holds about 6.44% of the health insurance market.
So, if you want access to its 45.6 million medical members, you should enroll in its network. The company operates in multiple states via different affiliates and offers Anthem-branded plans in 14 states.
6. Kaiser Foundation (Kaiser Permanente)
Kaiser dominates 6.01% of the market according to the same NAIC report. Hence, it is the 6th largest insurance payer in the U.S. But what makes it unique from other health insurance companies? This integrated managed care association has been in business for over 7 decades. It provides high-quality care and coverage to more than 12.5 million members in eight states.
In simple terms? It operates on a somewhat unique model, taking a more unified approach. It means it partners with a select network of exceptional providers, leading to a more concentrated network compared to other insurance payers.
To be more specific, its network includes 25,270 physicians, 73,283 nurses, 40 hospitals, and 612 medical offices. To access this integrated care and coverage model, you should definitely become a Kaiser provider. But keep in mind that this company’s credentialing process is largely internal.
7. HCSC Group
With $64.07 billion in policies collected in 2024, Health Care Service Corporation (HCSC) holds around 3.82% of the U.S. health insurance market. This makes it one of the top-rated health insurance companies to consider. One unique point about HCSC? It is the largest customer-owned health insurance company in the United States.
What about its key strength? Regional dominance in certain states. HCSC is an independent licensee of the Blue Cross Blue Shield Association. It primarily offers health plans in Illinois, Montana, New Mexico, Oklahoma, and Texas. Hence, providers in these states get access to a large share of local patients.
With more than 35,000 employees and coverage for over 26 million Americans, HCSC is an ideal option for practices seeking strong state-level reach.
8. The Cigna Group (Cigna Healthcare)
Cigna also has a significant network, covering Medicare, employer, and group prescription drug plans through Cigna Healthcare and Evernorth Health Services. The company has experienced significant growth since merging with Express Scripts, a pharmacy benefits management organization, in 2018.
It is also one of the largest health insurance companies with a global network of over 2 million healthcare providers, clinics, and facilities. In the U.S., the company serves over 15 million medical and more than 16 million dental customers via public and private employer relationships.
As for its market share, the company holds a 2.50% share of the U.S. insurance market, with direct written premiums exceeding $41.92 billion. In short, you can tap into a large employer-sponsored population by getting credentialed with Cigna.
9. Molina Healthcare Inc.
Molina Healthcare is the 9th largest health insurance payer in the U.S., with a market share of 2.14%. Founded in 1980, this managed care company specializes in government-sponsored healthcare insurance programs, such as Medicaid and Medicare. In short, it also focuses on underserved communities.
As for its medical members, Molina Healthcare insures over 5.8 million people nationwide, making it one of the top 10 health insurance companies. It is committed to delivering effective, reliable, and affordable healthcare. Hence, this company employs a community-based approach to meet the needs of every member.
Talking about numbers, Molina Healthcare generated $35.84 billion in direct written premiums in 2024. In short, its network can also connect you to many patients, especially if your practice mainly serves Medicaid populations. Therefore, you should join the Molina provider network.
10. Guidewell (Florida Blue)
Guidewell, previously known as GuideWell Mutual Holding Corporation, occupies the last spot on our list of the 10 largest medical insurance companies. Driven by $30.71 billion in direct written premiums, this non-profit mutual insurance holding company maintains a 1.83% market share in the latest NAIC report.
Created in 2013, Guidewell is a regional insurance payer, primarily focusing on Florida and some associated markets. A key company fact? It owns several innovative companies, including the well-known Florida Blue. Hence, it provides a wide range of insurance products to locals.
So, if you are also a provider in Florida, consider getting credentialed with Guidewell to improve your patient volume.
MediBillMD Makes Credentialing Easy
Leave your credentialing woes to our credentialing experts! Enrolling in the top health insurance companies’ networks, such as UHC, Centene, CVS, and Cigna, can help you access a larger patient base. However, their credentialing process is anything but simple, each requiring different steps and unique information.
In short, healthcare providers face notoriously long delays due to inconsistent credentialing standards. Our insurance credentialing services can help you avoid this stressful phase. At MediBillMD, we take the most time-consuming tasks off your hands so you can focus on other, more important things.
Our credentialing experts understand the requirements of these medical insurance companies and handle every step accordingly. To summarize, we can help you secure participation in top networks much faster. Therefore, partner with our experts to see your patients sooner.
