Program Data

Program Data

The Medicare Shared Savings Program (Shared Savings Program) makes data on Accountable Care Organizations (ACOs) publicly available through different sources. Find the most recent data on this webpage and For a complete list of publicly available data, reference Publicly Available Data Sources and ACO Performance Data (PDF) maintained by the Centers for Medicare & Medicaid Services (CMS). 

ACO Participation and Performance Data

Program Fast Facts

Provides summary information about the Shared Savings Program as of January 1, 2024, including the following:

  • Historical program information (including program size, quality, and shared savings)
  • ACO information (including characteristics, composition, and participation information)
  • ACO assigned beneficiary population

Shared Savings Program Fast Facts (PDF)

Previous Program Fast Facts are available in the Fast Facts Archives (ZIP)


Displays an interactive map of the U.S. pinpointing locations of Shared Savings Program ACOs and select details including the following:

  • ACO service area
  • ACO public contact information
  • ACO public reporting website

Visit the list of ACOs webpage and click “Visualize Data” to “Search for an ACO” in the interactive map.

List of ACOs

Provides organizational information about ACOs including the following:

  • Name
  • Start date
  • Track
  • Address
  • Service area
  • Public reporting website
  • Executive Contact information
  • Public Contact information

Shared Savings Program ACOs

List of ACO Participants

Shows a listing of ACO participants by ACO name.

Shared Savings Program ACO Participants

List of Skilled Nursing Facility Affiliates

Shows a listing of ACO Skilled Nursing Facility (SNF) affiliates by ACO name.

Shared Savings Program SNF Affiliates

List of Advance Investment Payments Spend Plans

Shows a listing of ACO use of Advance Investment Payments (AIP). 

Shared Savings Program AIP Spend Plans

ACO ID Crosswalk

This data set includes the ACO ID (Axxxx). Prior to July 2019, the data sets included an encrypted ACO ID (Axxxxx). Research Identifiable Files (RIFs) and Public Use Files (PUFs) created prior to July 2019 identify ACOs using the encrypted ACO ID. RIFs and PUFs created in July 2019 and later will identify ACOs using their un-encrypted ACO ID. To facilitate comparisons between data sets created before July 2019 and after July 2019, CMS is making a crosswalk available.

ACO ID Crosswalk (XLSX)     

ACO Public Use Files

To address the increasing number of requests for Shared Savings Program ACO data and to inform those interested in the policies finalized in the Shared Savings Program, CMS has created standard analytical files providing publicly available information.

  • Performance Year Financial and Quality Results: Provides financial and quality performance data for each de-identified ACO by performance year including the following:
    • Overall quality score
    • Final sharing rate
    • Minimum savings rate (MSR)
    • Minimum loss rate (MLR)
    • Benchmark
    • Assigned beneficiary demographic characteristics and provider/supplier composition
  • Advance Investment Payment Spend Plans PUF: Details the projected and actual use of advance investment payments by ACOs in each performance year.
  • Shared Savings Program Benchmark PUFs: Standard analytical files that can be used to inform those interested in the Shared Savings Program’s use of factors based on regional fee-for-service (FFS) expenditures in establishing, adjusting, updating and resetting historical benchmarks for ACOs (as applicable based on the ACO's agreement period start date). It is the intent of CMS to publish these PUFs annually, in the summer following the conclusion of the calendar year to which it relates and when any file updates are available.
    • County-level Aggregate Expenditure and Risk Score Data on Assignable Beneficiaries: Aggregate data consisting of per capita Parts A and B FFS expenditures, average CMS Hierarchical Condition Categories (CMS-HCC) prospective risk scores and total person-years for assignable beneficiaries by Medicare enrollment type (End Stage Renal Disease (ESRD), disabled, aged/dual eligible, aged/non-dual eligible) for each county.
    • Number of ACO Assigned Beneficiaries by County: Aggregate data consisting of total assigned beneficiaries by ACO for each county where at least one of their assigned beneficiaries resides. These data files include: ACO ID that is used on publicly released files, state ID (SSA state code), county ID (SSA county code), total person-years by Medicare enrollment type (ESRD, disabled, aged/dual eligible, aged/non-dual eligible), total assigned beneficiary person-years, and total number of beneficiaries contributing at least one person-month.

Research Identifiable Files

Certain identifiable performance year data is available through the Research Data Assistance Center (ResDAC) for a fee to researchers who obtain an appropriate Data Use Agreement (DUA).

  • Beneficiary-Level RIF: Beneficiary-identifiable data for every beneficiary assigned to a Shared Savings Program ACO, including ACO identifier, preliminary assignment, quarter of assignment, final assignment, unique beneficiary identifier, date of birth/death, gender, race, reason for Medicare eligibility, dual status, Part D enrollment status, and monthly eligibility flag.
  • Provider-Level RIF: Provider-identifiable data for institutional and individual providers who participated in a Shared Savings Program ACO during the performance year, including ACO name and start date, provider identifiers, and provider characteristics (facility type—institutions, practice type/specialty—individuals, count primarily served).


For additional information on Shared Savings Program ACOs, please visit

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Page Last Modified:
01/29/2024 03:14 PM