ACO Investment Model

The ACO Investment Model was an initiative designed for organizations participating as accountable care organizations (ACOs) in the Medicare Shared Savings Program (Shared Savings Program). The ACO Investment Model was a model of pre-paid shared savings that built on the experience with the Advance Payment Model. This model tested the use of pre-paid shared savings to encourage new ACOs to form in rural and underserved areas and to encourage current Medicare Shared Savings Program ACOs to transition to arrangements with greater financial risk.


CMS is encouraging providers to participate in ACOs through the Medicare Shared Savings Program, which creates financial incentives for ACOs that lower growth in health care costs while meeting performance standards on quality of care and putting Medicare beneficiaries first. The ACO Investment Model was developed in response to stakeholder concerns and available research suggesting that some providers lack adequate access to the capital needed to invest in infrastructure necessary to successfully implement population care management. CMS provided financial support to these ACOs to make infrastructure investments and develop new ways to improve care for Medicare beneficiaries.

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ACO Investment Model mapped


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The CMS ACO Investment Model (AIM) consisted of 45 participating ACOs (List), that served beneficiaries across 38 states, including 2 ACOs that began participating in the Model in 2015 and 43 ACOs that began participating in the Model in 2016. Two of these ACOs began participating the Shared Savings Program in 2013, two began participating in 2014, five began participating in 2015, and 36 began participating in 2016.

  • Access Care Oklahoma, LLC

  • Affiliated ACO, LLC

  • Akira Health of Los Angeles Inc

  • Akira Health, Inc.

  • Aledade Kansas ACO, LLC

  • Aledade Mississippi ACO, LLC

  • Aledade West Virginia ACO, LLC

  • Alliance ACO, LLC

  • AmpliPHY of Kentucky ACO LLC

  • AmpliPHY of Texas ACO LLC

  • Beacon Rural Health

  • California ACO

  • Carolina Medical Home Network Accountable Care Organization LLC

  • Citrus County ACO, LLC

  • Deep South Regional ACO

  • Great Plains Care Organization

  • Greater Michigan Rural ACO

  • Heartland Physicians ACO, Inc.

  • High Sierras-Northern Plains ACO

  • Illinois Rural ACO

  • Illinois Rural Community Care Organization LLC

  • Indiana Rural ACO

  • Iowa Rural ACO

  • Kentucky Primary Care Alliance

  • Magnolia-Evergreen ACO

  • Minnesota Rural ACO

  • MissouriHealth+

  • Mountain Prairie ACO

  • Mountain West ACO

  • New Hampshire Rural ACO

  • North Mississippi Connected Care Alliance

  • Ohio River Basin ACO

  • Oregon - Indiana ACO

  • Prairie Hills Care Organization

  • PremierMD ACO, LLC

  • Reid ACO

  • Rocky Mountain Accountable Care Organization, LLC

  • San Juan Accountable Care Organization, LLC

  • Southern Michigan Rural ACO

  • Suburban Health ACO 2

  • Sunshine ACO LLC

  • Tar River Health Alliance, LLC

  • Texas Rural ACO LLC

  • The Premier Healthcare Network LLC

  • Winding River ACO


Number of Beneficiaries: As of January 2017, AIM participants served a combined total of over 487,000 beneficiaries nationwide; an increase of 53,000 beneficiaries from January 2016.

ACO Infrastructure: 27 ACOs reported having a Critical Access Hospital (CAH) or Inpatient Prospective Payment System (IPPS) hospital with fewer than 100 beds as part of their ACO structure.

Geographic Coverage of AIM Participants among 38 States:

  • Northeast: Maine, Maryland, New Hampshire, Pennsylvania, Vermont
  • South: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, West Virginia
  • Midwest: Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, Wisconsin
  • West: Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Washington, Wyoming

Rural Location: The AIM encouraged ACO development in rural and underserved areas. Of the 45 participants, 36 had at least 65 percent of their delivery sites in rural areas.

Quality of Care (existing ACOs only): Both of the previously existing ACOs met or exceeded the median quality performance rate compared to all ACOs on at least 70 percent of the most recent reported measures when they applied.

Financial Performance (existing ACOs only): Of the 2 previously existing ACOs, 1 ACO achieved their assigned financial benchmark in their first performance year.

Initiative Details

Participation in the ACO Investment Model was limited to two distinct groups:

  • New Shared Savings Program ACOs starting in 2015 and 2016 - The ACO Investment Model sought to encourage uptake of coordinated, accountable care in rural geographies and areas where there has been little ACO activity, by offering pre-payment of shared savings in both upfront and ongoing per beneficiary per month payments.
  • ACOs that joined Shared Savings Program starting in 2012, 2013 and 2014 - The ACO Investment Model helped ACOs succeed in the shared savings program and encouraged progression to higher levels of financial risk, ultimately improving care for beneficiaries and generating Medicare savings.

Under the ACO Investment Model, ACOs that began participating on January 1, 2015 or January 1, 2016 received three types of payments:

  • An upfront, fixed payment:  Each ACO received a fixed payment.
  • An upfront, variable payment:  Each ACO received a payment based on the number of its preliminarily prospectively-assigned beneficiaries.
  • A monthly payment of varying amount depending on the size of the ACO:  Each ACO received a monthly payment based on the number of its preliminarily prospectively-assigned beneficiaries.

The structure of these payments addressed both the fixed and variable costs associated with forming an ACO.

Under the ACO Investment Model, ACOs that began participating in the Medicare Shared Savings program on April 1, 2012 or July 1, 2012, January 1, 2013, or January 1, 2014 received two types of payments:

  • An upfront, variable payment:  Each ACO received a payment based on the number of its preliminarily prospectively-assigned beneficiaries.
  • A monthly payment of varying amount depending on the size of the ACO:  Each ACO received a monthly payment based on the number of its preliminarily prospectively-assigned beneficiaries.


In order to be eligible for the ACO Investment Model, an ACO must have met the following criteria:

  • The ACO must be accepted into and participate in the Shared Savings Program. The ACO’s first performance period in the Medicare Shared Savings Program must have started in 2012, 2013, 2014, 2015 or 2016.
  • The ACO has completely and accurately reported quality measures to the Medicare Shared Savings Program in the most recent performance year, if the ACO started in the Medicare Shared Savings Program in 2012, 2013 or 2014, excluding ACOs starting in 2015 or 2016. The ACO had a preliminary prospective beneficiary assignment of 10,000 or fewer beneficiaries for the most recent quarter, as determined in accordance with the Shared Savings Program regulations. Unless an ACO that started in 2015 or will start in 2016 in determined to be from a rural area using the application selection criteria.
  • The ACO did not include a hospital as an ACO participant or an ACO provider/supplier (as defined by the Shared Savings Program regulations), unless the hospital was a critical access hospital (CAH) or inpatient prospective payment system (IPPS) hospital with 100 or fewer beds.
  • The ACO was not owned or operated in whole or in part by a health plan.
  • The ACO did not participate in the Advance Payment Model.

During the selection process, the ACO Investment Model targeted ACOs serving rural areas and areas of low ACO penetration and existing ACOs committed to moving to higher risk tracks. CMS also gave preference to ACOs that provided high quality of care, ACOs that achieved their financial benchmark, ACOs that demonstrated exceptional financial need, and those that submitted compelling proposals for how they will invest both their own funds and CMS funds.

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Latest Evaluation Report

Prior Evaluation Reports

Additional Information

Where Health Care Innovation is Happening