MSSP and ACO Proposed Changes 2026: What Clinicians Need To Know About Proposed Rule Changes
As we move into 2026, the Centers for Medicare and Medicaid Services (CMS) has introduced a new set of proposed changes that will impact Accountable Care Organizations (ACOs) participating in the Medicare Shared Savings Program (MSSP). While some core program elements will remain consistent, there are key revisions that ACOs should be aware of in order to ensure compliance and optimize performance. This blog post will highlight the most important updates and what they mean for ACOs in 2026.
1. ACO Participation & Risk Models
Current Policy: ACOs may remain in a one-sided risk model (no downside financial risk) for up to 7 years
Proposed Change: New ACOs will be limited to 5 years in a one-sided risk model before transitioning to two-sided risk (potential losses but higher rewards)
Goal of Change: Encourage earlier adoption of financial accountability to drive cost savings for Medicare.
2. Minimum Patient Requirement Flexibility
Current Policy: ACOs are required to maintain a minimum of 5,000 attributed Medicare beneficiaries in all three benchmark years
Proposed Update: ACOs would only need to meet the 5,000 patient threshold in the third benchmark year, allowing more flexibility in years one and two.
Important Caveats
ACOS falling below 5,000 patients in any year will not be eligible for the high-risk ENHANCED track
Shared savings and losses will be capped at lower levels to limit financial exposure for Medicare.
3. Quality Reporting Changes
Healthy Equity Adjustment Removed (2025+): ACOs will no longer earn bonus points for serving low-income or dual-eligible patients, as CMS says other risk adjustments already account for this
Simplified Reporting: ACOs only need to report quality data for patients who received primary care from them, reducing administrative workload.
Quality Measures Updates:
Removed: Screening for Social Drivers of Health (Quality ID 487)
New Option (2027): Patients can complete CAHPS surveys online, in addition to mail and phone.
4. Cyberattack Protections
- ACOs hit by ransomware/cyberattacks can apply for relief from penalties if they can’t meet quality/financial goals.
5. Other Key Updates
Changes of Ownership (CHOW): ACOs must update participants lists when a clinic or hospital changes ownership mid-year.
Expanded Primary Care Definition (2026): Behavioral health services will not count towards patient assignment.
Benchmark Terminology Update: The “health equity adjustment” is being renamed “population adjustment”, but still supports ACOs serving low-income populations.
Stricter Quality Monitoring (2026): ACOs must meet both the original and alternative quality standards to avoid penalties.
Quality Measures:
The list below displays the list of the quality measures to be included in the APP Plus quality measure set for Shared Savings Program ACOs as finalized in the CY 2025 PFS final rule and with the proposed removal of Quality ID: 487 Screening for Social Drivers of Health from the APP Plus quality measure set.
Quality Measures in the APP Plus Quality Measure Set for Shared Savings Program ACOs
2025 Performance Year Measures:
321 – CAHPS for MIPS
Collection Type: CAHPS for MIPS Survey479 – Hospital-Wide, 30-Day, All-Cause Unplanned Readmission (HWR) Rate
Collection Type: Administrative Claims001 – Diabetes: Glycemic Status Assessment Greater Than 9%
Collection Type:eCQM/MIPS CQM/Medicare CQM (2025–2026)
eCQM/Medicare CQM (2027+)
134 – Depression Screening and Follow-Up
Collection Type:eCQM/MIPS CQM/Medicare CQM (2025–2026)
eCQM/Medicare CQM (2027+)
236 – Controlling High Blood Pressure
Collection Type:eCQM/MIPS CQM/Medicare CQM (2025–2026)
eCQM/Medicare CQM (2027+)
112 – Breast Cancer Screening
Collection Type:eCQM/MIPS CQM/Medicare CQM (2025–2026)
eCQM/Medicare CQM (2027+)
2026 Performance Year Measures:
113 – Colorectal Cancer Screening
Collection Type:eCQM/MIPS CQM/Medicare CQM (2026)
eCQM/Medicare CQM (2027+)
484 – Hospital Admission Rates for Patients with Multiple Chronic Conditions
Collection Type: Administrative Claims
2027 Performance Year Measure:
305 – Initiation and Engagement of Substance Use Disorder Treatment
Collection Type: eCQM/Medicare CQM
2028 Performance Year (or Later):
493 – Adult Immunization Status
Collection Type: eCQM/Medicare CQM
Phase-In: 2028 or the first performance year after specifications become available
Proposal to Add a Web-based Survey Mode to the CAHPS for MIPS Survey
Shared Savings Program ACOs are required to administer the CAHPS for MIPS Survey annually to meet the program’s quality reporting requirements. Currently, the survey is conducted using a mail-phone protocol. To help improve response rates, CMS has proposed transitioning to a web-mail-phone protocol beginning with the 2027 performance year. Under this proposal, the existing mail-phone method would be discontinued.
Bottom Line
CMS wants ACOs to take on risk faster, simplifies some rules, and adjusts quality reporting—while protecting against cyberattacks and ownership changes.
Next Steps
Public comments on the proposed changes are open through September 12, 2025. CMS is expected to release the final rule later in the year, with most updates set to take effect in January 2026 or 2027.
Read the full CMS Fact Sheet Here
How Chirpy Bird Can Help
With our team of APM and ACO experts, Chirpy Bird offers personalized guidance and support for all aspects of ACO Quality and Promoting Interoperability. From navigating CMS rule changes to optimizing your reporting strategy, we’re here to ensure your organization stays compliant and performs at its best.
📨 Reach us at hello@chirpybirdinc.com or give us a call at 888-647-7247 — we’d love to help your ACO succeed.
