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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. But with so many ACOs out there, which ones are serving the most patients? Let’s analyze the top 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 ConncectedCareView, 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. 

Top 25 ACOs by patient population size

RankACO nameDefinitive IDStatePatient populationExplore dataset
1TMA PracticeEdge (Texas Medical Association - Blue Cross and Blue Shield of Texas ACO)810909TX5,000,000Explore
2Aetna - Childrens Hospital of Philadelphia (CHOP) ACO842940PA1,400,000Explore
3Aetna - Carilion Clinic ACO552289VA1,000,000Explore
4Capital Bluecross - Heritage Medical Group ACO552388PA700,000Explore
5Anthem Blue Cross of California - Healthcare Partners ACO579844CA675,000Explore
6Aetna - Riverside Health System ACO579912VA500,000Explore
7Horizon Blue Cross Blue Shield of New Jersey - Partners in Care ACO585269NJ500,000Explore
8Aetna - Virtual Medical Group ACO823406NJ400,000Explore
9Advocatecare ACO552285IL375,000Explore
10BCBS Illinois - Advocate Physician Partners Accountable Care969400IL375,000Explore
11BCBS Arizona - Banner Health Network ACO969315AZ350,000Explore
12Cigna - Banner Health Network ACO553402AZ350,000Explore
13UnitedHealthcare - Seton Health Alliance ACO577487TX320,000Explore
14Partners for Kids ACO578002OH300,000Explore
15HealthPartners - Northwest Metro Alliance969460MN300,000Explore
16Blue Shield of California - EPIC ACO585460CA273,000Explore
17University Hospitals - Anthem Blue Cross and Blue Shield ACO835846OH270,000Explore
18Cigna - DeKalb Physicians Health Organization947978GA250,000Explore
19Cigna - Westmed Medical Group ACO552351NY237,000Explore
20OptumCare - North American Medical Management California ACO553396CA229,000Explore
21Rainbow Care Connection574791OH200,000Explore
22Health Choice Utah777076UT200,000Explore
23Humana - John Muir Health ACO856423CA200,000Explore
24Humana - University Hospitals Accountable Care Organization969514OH181,500Explore
25UHACO medical plan - University Hospitals Accountable Care Organization780659OH181,500Explore

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 June 2024.

Which ACO has the largest patient population? 

TMA PracticeEdge, a commercial ACO based in Austin, TX, has the highest patient population at 5 million as of June 2024. Aetna-Children’s Hospital of Philadelphia (CHOP) is in second place with a patient population of 1.4 million.  Coming in third place is Aetna – Carilion Clinic, a commercial ACO based out of Roanoke, VA, with a population of 1 million patients. 

The top 25 ACOs by patient population on the list represent more than 15 million patients with an average population of 613,420 patients each. Of the top 25, 22 are commercial ACOs and two are Medicaid 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 cover patients who are covered by different types of healthcare payors. The main types of ACOs are: 

  • Commercial ACOs: Usually provider groups establish an accountable care payment model with a non-government payor. 
  • Medicaid ACOs: Aligns providers and payors incentives with a focus on value for a Medicaid population. 
  • Medicare Shared Savings Program: Requires measurement and improvement in quality and an annual certification process. 

Learn more 

Healthcare Insights are developed with healthcare commercial intelligence from the Definitive Healthcare platform. Want even more insights? Start a free trial today and get access to the latest healthcare commercial intelligence on hospitals, physician groups, ACOs, and other providers.