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June 1, 2021 

The Honorable Chiquita Brooks-LaSure
Centers for Medicare and Medicaid Services
U.S. Department of Health and Human Services
Hubert H. Humphrey Building
200 Independence Avenue, S.W.
Washington, DC 20201 

Re: Extending the Medicare Shared Savings Program Application Dates and Deadlines 

Dear Administrator Brooks-LaSure: 

The National Association of ACOs (NAACOS) congratulates you on your confirmation as administrator of the Centers for Medicare & Medicaid Services (CMS). You have built a career working to expand affordable health coverage to millions of Americans. As our health system continues to deal with the COVID-19 pandemic, your tenure comes at a critical time, dealing with issues from spending and costs to coverage and access. NAACOS and our members stand ready to help you tackle these issues and others. 

Today, we write to express our concern regarding abbreviated and narrow deadlines for accountable care organizations (ACOs) applying to participate in the Medicare Shared Savings Program (MSSP) for 2022. In the name of creating a streamlined application cycle, CMS asks ACOs for critical information like lists of participant providers far sooner in the calendar year than it has historically required. Coupled with narrow windows in which to submit documents like a Notice of Intent to Apply (NOIA), NAACOS fears that without additional flexibilities, participation will suffer in a program that is already operating under declining participation. 

NAACOS represents more than 12 million beneficiary lives through hundreds of organizations participating in population health-focused payment and delivery models in Medicare, Medicaid, and commercial insurance. Models include the MSSP, the Next Generation (Next Gen) ACO Model, the Direct Contracting Model, and alternative payment models supported by a myriad of commercial health plans and Medicare Advantage. NAACOS is a member-led and member-owned nonprofit organization that works to improve quality of care, outcomes, and healthcare cost efficiency.  

NAACOS is concerned with shrinking turnaround times for application information and deadlines coming sooner in the performance year, as detailed on the chart below. For example, ACOs have just a week to submit NOIAs, which are required to be eligible to apply later. ACOs were given a month in 2017 and two weeks in 2019. The application window this year is set to close on June 28, when in the past it closed in late July or early August. NAACOS is also concerned with the early August deadline to add ACO participants. This comes nearly six weeks sooner than when this information was due in 2019. 

Additional time is needed to ensure ACOs may work with potential participant providers and work through scenarios in which adding providers might change participation options. For example, adding certain practices may cause an ACO’s revenue status to change to “high” or “low,” which determines which level of risk on MSSP’s glidepath an ACO may enter. NAACOS asks that CMS grant ACOs an additional week to submit a NOIA and subsequently extend the application window into July. More time should be granted to allow ACOs to add participants to their ACO. There is little reason to require such early deadlines this year. 

There is CMS precedent for our request. In 2017, CMS extended the application window by an additional five business days from July 31 to August 4. The agency subsequently extended the application process by an additional week. A similar move in 2021 would allow ACOs more time to work with their networks and discuss participation options with partnering providers. 

MSSP Application Deadlines for This Year and Previous Four Years







Window for Notice of Intent to Apply


June 1–7

Application period canceled, citing COVID-19

June 11–28

No application period held because of Pathways to Success rulemaking

May 1- 31

Application window

June 8–28

July 1–29

July 1- 31*

*Later extended to Aug. 4


Final Opportunity to add ACO participants

Aug. 3

Sept. 19

Aug. 30*

*Later extended to Sept. 6


Final Opportunity to withdraw or delete ACO participants


Sept. 10

Sept. 19

Oct. 26

Deadlines are for participation in following performance year. 

Without some relief, we fear ACO participation will suffer. To start 2021, 477 ACOs are participating in the MSSP, down from a high of 561 in 2018 and the lowest since 480 participated in 2017, the Trump administration’s first year in office. In contrast to the diminishing number of ACOs, the MSSP continued to produce greater savings every year and saw its best year yet in 2019, the most recent year for which data are available. Serving 11.2 million seniors in 2019, the MSSP saved Medicare $2.6 billion and $1.2 billion after accounting for shared savings bonuses and collecting shared loss payments. Since 2012, ACOs, including those in the MSSP and Next Gen Model, along with a now expired Pioneer ACO Model, have saved Medicare $8.5 billion and $2.5 billion after accounting for shared savings payments, shared loss payments. 

As we’ve noted before, President Biden inherits fewer ACOs than the Obama administration left at the start of 2017. We still hope that trend will be reversed under your tenure, given the growing track record of success ACOs have in improving outcomes, bettering quality, and overall improving the value that traditional Medicare beneficiaries receive. We hope you heed our concerns about provide additional time during the 2022 application window. Please contact Allison Brennan, NAACOS’s senior vice president of government affairs, at 202-725-7129 or at [email protected], if you have additional questions. 


Clif Gaus, Sc.D.
President and CEO