Healthcare Insights
Top 25 ACOs by patient population
The healthcare landscape is changing, with a growing focus on accountable care organizations (ACOs) that prioritize quality care and cost-effectiveness. For organizations operating in this space, scale is one important signal of potential impact, but it should be considered alongside incentive structure, risk exposure, and operational maturity, among other ACO factors.
Below is a data-driven look at the ACOs in the U.S. that serve the largest patient populations.
What are accountable care organizations (ACOs)?
Accountable care organizations are formal groups of physicians, hospitals, or other care providers that voluntarily work together to deliver coordinated care to a defined population of patients. ACOs are a key part of the move toward value-based care.
ACOs aim to ensure that patients—especially those living with chronic conditions—receive the appropriate care they need when they need it, while preventing unnecessary duplication of services, medical errors, and expenses.
Looking for a list of the largest ACOs in the U.S. ranked by patient population?
Using ConnectedCareView, we’ve compiled a list of the top 25 ACOs in the U.S. ranked by their total patient population, according to the most recent 12-month interval in our database.
| Rank | ACO name | State | Patient population | Explore dataset |
|---|---|---|---|---|
| 1 | TMA PracticeEdge (Texas Medical Association - Blue Cross and Blue Shield of Texas ACO) | TX | 5,000,000 | Explore |
| 2 | Aetna - Childrens Hospital of Philadelphia (CHOP) ACO | PA | 1,400,000 | Explore |
| 3 | Aetna - Carilion Clinic ACO | VA | 1,000,000 | Explore |
| 4 | Capital Bluecross - Heritage Medical Group ACO | PA | 700,000 | Explore |
| 5 | Anthem Blue Cross of California - Healthcare Partners ACO | CA | 675,000 | Explore |
| 6 | Horizon Blue Cross Blue Shield of New Jersey - Partners in Care ACO | NJ | 500,000 | Explore |
| 7 | Aetna - Riverside Health Source LLC | VA | 500,000 | Explore |
| 8 | Aetna - Virtual Medical Group ACO | NJ | 400,000 | Explore |
| 9 | Advocatecare ACO | IL | 375,000 | Explore |
| 10 | BCBS Illinois - Advocate Physician Partners Accountable Care | IL | 375,000 | Explore |
| 11 | Cigna - Banner Health Network ACO | AZ | 350,000 | Explore |
| 12 | BCBS Arizona - Banner Health Network ACO | AZ | 350,000 | Explore |
| 13 | Caravan Collaborative Pathways (AKA Caravan Health ACO 22 LLC) | TX | 328,733 | Explore |
| 14 | UnitedHealthcare - Seton Health Alliance ACO | TX | 320,000 | Explore |
| 15 | Partners for Kids ACO | NY | 300,000 | Explore |
| 16 | HealthPartners - Northwest Metro Alliance | MN | 300,000 | Explore |
| 17 | Anthem Blue Cross and Blue Shield - University Hospitals ACO | OH | 270,000 | Explore |
| 18 | Cigna - DeKalb Physicians Health Organization | GA | 250,000 | Explore |
| 19 | Cigna - Westmed Medical Group ACO | NY | 237,000 | Explore |
| 20 | OptumCare - North American Medical Management California ACO | CA | 229,000 | Explore |
| 21 | Humana - John Muir Health ACO | CA | 200,000 | Explore |
| 22 | Health Choice Utah | UT | 200,000 | Explore |
| 23 | UHACO Medical Plan - University Hospitals Accountable Care Organization | OH | 181,500 | Explore |
| 24 | University Hospitals Coordinated Care (AKA Aetna - University Hospitals ACO) | OH | 181,500 | Explore |
| 25 | UnitedHealthcare of Ohio - University Hospitals ACO | OH | 181,500 | Explore |
Fig. 1 Data from the Definitive Healthcare ConnectedCareView product. ACO data is sourced from the Centers for Medicare & Medicaid Services and proprietary research. Data accessed May 2026.
Which ACO has the largest patient population?
TMA PracticeEdge, a commercial ACO affiliated with the Texas Medical Association and Blue Cross and Blue Shield of Texas, has the largest patient population among U.S. accountable care organizations, serving approximately 5 million patients. The next largest ACO is Aetna–Children’s Hospital of Philadelphia (CHOP), with 1.4 million patients, followed by Aetna–Carilion Clinic in Virginia, which serves roughly 1 million patients.
Collectively, the 25 largest ACOs serve nearly 17 million patients. Patient populations among these organizations range from 181,500 to 5 million, with an average of approximately 679,000 patients per ACO. Commercial ACOs dominate the ranking, accounting for 21 of the top 25 organizations, while the remaining four include Medicaid and Medicare Shared Savings Program ACOs.
How many ACOs are there in the U.S.?
Definitive Healthcare tracks more than 1,800 active ACOs across the U.S. Our list of accountable care organizations by state highlights the states with the most and fewest ACOs.
You can also review analyses of ACOs by state, including rankings of the top ACOs in Texas and the top ACOs in Florida.
What are the different types of ACOs?
ACOs operate across different types of healthcare payors, including commercial insurers, Medicaid programs, and Medicare. A few key examples include:
- Commercial ACOs: Arrangements between provider organizations and private payors (such as health plans or employers) designed to align payment with value-based care performance.
- Medicaid ACOs: State-specific programs that align provider and payor incentives to improve care quality and cost efficiency for Medicaid populations.
- Medicare Shared Savings Program: A federal CMS program in which provider organizations form ACOs that are held accountable for quality performance and total cost of care for Medicare beneficiaries, with the opportunity to share in savings (or losses) relative to spending benchmarks.
Learn more
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