Flawed Benchmark Policy Taxes Accountable Care’s Most Successful Providers
May 6, 2026
Medicare’s unprecedented and unpredictable spending growth in recent years is penalizing clinicians who have been most effective at slowing cost growth and improving care. The Accountable Care Prospective Trend (ACPT) in the Medicare Shared Savings Program (MSSP) could cost accountable care clinicians more than $700 million in lost shared savings for care delivered in 2025. These reductions are the result of inaccurate forecasting embedded directly into MSSP benchmarks.
How ACPT Went from Solution to Systemic Risk
The Centers for Medicare and Medicaid Services (CMS) created the ACPT to address a legitimate concern: benchmark ratcheting that occurs when ACOs successfully slow spending growth. The agency designed ACPT to “allow for benchmarks to increase beyond actual spending growth rates as ACOs slow spending growth,” helping preserve incentives for continued participation and investment in accountable care. CMS acknowledged early on that this approach carries challenges, noting that “there are circumstances that may warrant reducing the weight placed on the ACPT on an ad hoc basis.”
Unfortunately, what seemed as a possibility is now the standard as the ACPT has introduced a new cycle of uncertainty and financial exposure – one where ACOs must wait each year to see whether CMS’ spending projections align with reality or whether retrospective adjustments will be needed to correct the damage.
Projection Errors with Real Consequences
The magnitude of recent forecasting errors illustrates the problem.
- In 2024, the ACPT missed actual Medicare spending growth by 94 percent. CMS used its ad hoc authority to reduce the weight of the ACPT, limiting, but not eliminating, the harm to ACOs. As a result, there was $187 million cut to ACOs’ shared savings.
- In 2025, spending was nearly 60 percent higher than ACPT projections, impacting nearly 500,000 clinicians.
These represent fundamental failures in benchmarking that undermine confidence in MSSP and distort financial outcomes.
Why the ACPT Keeps Missing the Mark
ACPT’s challenges tie back to the use of United States Per Capita Cost (USPCC) growth projections. In recent years, USPCC has proven to be a poor predictor of actual spending trends, particularly during periods of rapid change in utilization patterns and pricing.
Beyond this flaw, ACPT:
- Does not account for sudden price increases, such as those from new technologies or high-cost pharmaceuticals
- Fails to reflect regional variation in spending growth
- Does not adjust for fraud, waste, and abuse, which can dramatically distort observed costs but remain outside ACOs’ control
The projection systematically overshoots or undershoots reality, leaving ACOs on the hook for CMS’ own forecasting errors.
Fix ACPT Now
CMS has already acknowledged these flaws and shifted its approach in other models. In the Center for Medicare and Medicaid Innovation’s new LEAD model, CMS included explicit ACPT guardrails to protect participants from the volatile and unreliable trend projection. Those guardrails provide predictability, allowing participants to focus on care transformation rather than financial survival.
Yet more than 400 ACOs in MSSP — CMS’ only permanent accountable care model — remain exposed to risk from ACPT.
The Path Forward: Predictability and Fair Accountability
CMS must align benchmark policy in MSSP with real-world conditions. That means:
- Reweighting ACPT in 2025 to zero.
- Establishing clear, automatic guardrails to prevent massive retrospective losses from projection errors in future years.
Accountable care works when incentives are credible, benchmarks are fair, and success is rewarded. Fixing the ACPT is necessary to sustain Medicare’s most successful alternative payment model.
We look forward to continuing to work with CMS to ensure sustainable accountable care for the future. For more information and to access templated resources and other tools for sharing the challenges ACOs face with ACPT, go to FixACPTNow.org.