An Accountable Care Organization (ACO) is a formal group of physicians, hospitals, or other care providers that voluntarily work together to deliver high-quality coordinated care to Medicare beneficiaries. The goal of an ACO is to provide affordable care through reducing or eliminating unnecessary duplication of tests or services, lowering the risk of medical errors. For each ACO, there is a defined patient population, primarily composed of Medicare beneficiaries, for which it is held accountable in terms of care cost, gross savings, and quality.
The following list highlights the top 25 ACOs by patient population, representing over 15.7 million patients with an average population of 628,000. Of the top 25, 92 percent are classified as commercial ACOs— an ACO model with a non-government payer.
TMA PracticeEdge, a commercial ACO based out of Austin, TX, ranks first with a patient population of five million — 112-percent higher than the next highest ACO, Aetna-Children’s Hospital of Philadelphia (CHOP) which has a patient population of 1.4 million.
Definitive's Healthcare Insights are developed with data from the Definitive Healthcare platform. Want even more insights? Start a Free Trial now and get access to the highest quality data and intelligence on hospitals, physicians, and other healthcare providers.
| Rank | Definitive ID | ACO Name | ACO Type | City | State | ACO Start Date | Patient Population | Explore This Dataset |
| 1 | 810909 | TMAPracticeEdge(Texas Medical Association - Blue Cross and Blue Shield of Texas ACO) | Commercial ACO | Austin | TX | 2015 Q1 | 5,000,000 | Explore This Profile |
| 2 | 842940 | Aetna -ChildrensHospital of Philadelphia (CHOP) ACO | Commercial ACO | Philadelphia | PA | 2015 Q4 | 1,400,000 | Explore This Profile |
| 3 | 552096 | Steward Integrated Care Network | Medicare Next Generation ACO | Needham | MA | 2016 Q1 | 1,000,000 | Explore This Profile |
| 3 | 552289 | Aetna - Carilion Clinic ACO | Commercial ACO | Roanoke | VA | 2011 Q3 | 1,000,000 | Explore This Profile |
| 5 | 552388 | CapitalBluecross- Heritage Medical Group ACO | Commercial ACO | Lemoyne | PA | 2011 Q2 | 700,000 | Explore This Profile |
| 6 | 579844 | Anthem Blue Cross of California - Healthcare Partners ACO | Commercial ACO | Torrance | CA | 2013 Q4 | 675,000 | Explore This Profile |
| 7 | 579912 | Aetna - Riverside Health System ACO | Commercial ACO | Newport News | VA | 2013 Q2 | 500,000 | Explore This Profile |
| 7 | 585269 | Horizon Blue Cross Blue Shield of New Jersey - Partners in Care ACO | Commercial ACO | East Brunswick | NJ | 2014 Q1 | 500,000 | Explore This Profile |
| 9 | 823406 | Aetna - Virtual Medical Group ACO | Commercial ACO | Marlton | NJ | 2015 Q1 | 400,000 | Explore This Profile |
| 10 | 552285 | AdvocatecareACO | Commercial ACO | Chicago | IL | 2011 Q1 | 375,000 | Explore This Profile |
| 10 | 969400 | BCBS Illinois - Advocate Physician Partners Accountable Care | Commercial ACO | Rolling Meadows | IL | 2012 Q3 | 375,000 | Explore This Profile |
| 12 | 969315 | BCBS Arizona - Banner Health Network ACO | Commercial ACO | Phoenix | AZ | 2012 Q1 | 350,000 | Explore This Profile |
| 12 | 553402 | Cigna - Banner Health Network ACO | Commercial ACO | Phoenix | AZ | 2012 Q4 | 350,000 | Explore This Profile |
| 14 | 577487 | UnitedHealthcare - Seton Health Alliance ACO | Commercial ACO | Austin | TX | 2013 Q3 | 320,000 | Explore This Profile |
| 15 | 578002 | Partners for Kids ACO | Medicaid ACO | Columbus | OH | 2012 Q3 | 300,000 | Explore This Profile |
| 15 | 969460 | HealthPartners - Northwest Metro Alliance | Commercial ACO | Bloomington | MN | 2010 Q1 | 300,000 | Explore This Profile |
| 17 | 585460 | Blue Shield of California - EPIC ACO | Commercial ACO | Redlands | CA | 2014 Q1 | 273,000 | Explore This Profile |
| 18 | 835846 | University Hospitals - Anthem Blue Cross and Blue Shield ACO | Commercial ACO | Cleveland | OH | 2015 Q3 | 270,000 | Explore This Profile |
| 19 | 849729 | Humana - DeKalb PHO ACO | Commercial ACO | Decatur | GA | 2016 Q1 | 250,000 | Explore This Profile |
| 19 | 858080 | DeKalb Medical Physicians Group - UnitedHealthcare ACO | Commercial ACO | Decatur | GA | 2016 Q3 | 250,000 | Explore This Profile |
| 19 | 947978 | Cigna - DeKalb Physicians Health Organization | Commercial ACO | Decatur | GA | 2015 Q4 | 250,000 | Explore This Profile |
| 22 | 552351 | Cigna -WestmedMedical Group ACO | Commercial ACO | Purchase | NY | 2012 Q2 | 237,000 | Explore This Profile |
| 23 | 553396 | OptumCare- North American Medical Management California ACO | Commercial ACO | Ontario | CA | 2012 Q4 | 229,000 | Explore This Profile |
| 24 | 574791 | Rainbow Care Connection | Commercial ACO | Cleveland | OH | 2012 Q3 | 200,000 | Explore This Profile |
| 24 | 777076 | Health Choice Utah | Medicaid ACO | South Jordan | UT | 2013 Q1 | 200,000 | Explore This Profile |
Fig 1. Data from Definitive Healthcare from the Accountable Care Organizations Database. Data is from the Center for Medicare & Medicaid Services and Definitive Healthcare proprietary data. Most recent data available, accessed in April 2020.