What Is the Medicare Shared Savings Program (MSSP)? ACO Guide for Providers

Key Takeaways

Here is the short version before the details below:

• What it is: The Medicare Shared Savings Program (Shared Savings Program) is Medicare's permanent, voluntary accountable care organization (ACO) program, tying a share of Medicare savings to lower spending and strong quality.
• How you get paid: An ACO earns a percentage of the difference when its assigned population's spending comes in under a CMS benchmark by more than a minimum savings rate, and it meets the quality standard.
• Two tracks: The BASIC track offers a lower-risk glide path (Levels A through E), and the ENHANCED track carries the highest risk and the highest reward.
• The track record: ACOs earned $4.1 billion in performance payments and saved Medicare $2.5 billion, the strongest results to date.
• Where the work happens: Shared savings turn on total cost of care, so managing high-risk patients between visits with remote monitoring and chronic care coordination is central to the result.

What Is the Medicare Shared Savings Program?

The Shared Savings Program is Medicare's largest and permanent accountable care program, authorized under the Affordable Care Act. Groups of doctors, hospitals, and other providers form an accountable care organization (ACO) and agree to be held accountable for the quality, cost, and experience of care for a defined population of Medicare fee-for-service (FFS) beneficiaries.

When an ACO delivers high-quality care and spends Medicare dollars more efficiently, it may share in the savings it generates; in two-sided arrangements, it may also owe money back if spending runs over.

Participation is voluntary and structured in multi-year agreements. According to CMS, ACOs commit to agreement periods of at least five years, made up of performance years that follow the same operational cycle. Currently, 511 Shared Savings Program ACOs serve 12.6 million people with Traditional Medicare through more than 700,000 participating providers and organizations, a 12.3 percent increase from the previous year.

To participate, an ACO must have at least 5,000 assigned beneficiaries, so many independent practices join an existing ACO rather than form their own.

The program sits inside Medicare's broader shift from paying for volume to paying for value. For the wider context on that shift, our explainer on value-based care implementation walks through how providers move from fee-for-service into accountable models.

How MSSP Shared Savings Are Calculated: Benchmark, MSR, and Quality

Payment under the Shared Savings Program follows a benchmark-and-threshold logic rather than a per-service fee. CMS sets each ACO a spending benchmark for its assigned beneficiaries, essentially a target for what that population's care should cost. Performance is then measured against that target.

• Benchmark: CMS establishes an expected-spending benchmark for the ACO's assigned population, adjusted for factors such as risk and regional trends.
• Minimum savings rate (MSR): Actual per-capita spending has to come in below the benchmark by more than a set MSR threshold before any savings count, which screens out normal year-to-year noise.
• Quality gate: The ACO must meet the quality performance standard (or the alternative standard) to be paid; hitting the spending target while failing quality does not earn full payment.
• Sharing rate: When both conditions are met, the ACO receives a percentage of the savings, set by its track and level, and total shared savings are capped as a percentage of the benchmark.

In two-sided models, the logic runs the other way when spending exceeds the benchmark: the ACO owes CMS a share of the losses, again subject to a rate and a cap. That trade-off of higher potential reward for downside exposure is the core choice an ACO makes when it selects a track.

The Two MSSP Tracks: BASIC vs. ENHANCED

ACOs choose between two tracks, which differ in how much risk they carry and how large a share of savings they can keep.

The table below summarizes the structure per CMS methodology specifications:

*Program parameters change through annual rulemaking; verify current-year requirements against CMS before making a track decision.

A few points a provider organization weighing a track should hold onto. The BASIC track is the on-ramp: eligible ACOs can begin under a one-sided model, where they share in savings but owe nothing back for losses, then phase into two-sided risk across the glide path. The ENHANCED track is two-sided for the full agreement period and offers the highest sharing rate, up to 75 percent, alongside the highest downside exposure.

Track choice also carries a Quality Payment Program consequence: clinicians in BASIC Level E or the ENHANCED track are treated as participating in an Advanced Alternative Payment Model (Advanced APM), while Levels A through D fall under the Merit-based Incentive Payment System (MIPS), per CMS.

The program's direction of travel is toward risk. ACOs in the highest-risk levels generated the largest share of savings, and CMS has continued to use rulemaking to steer ACOs toward two-sided models over time. Currently, 82.8 percent of Shared Savings Program ACOs are in BASIC Level E or the ENHANCED track, the highest share since the program began, per CMS.

What the Medicare Shared Savings Program Results Show

The Shared Savings Program has moved from an experiment into Medicare's largest accountable care model, and its financial results matter for any organization modeling the opportunity. In the most recent year CMS reconciled, the program produced its strongest results to date, and a few patterns have held steady across reporting cycles.

The figures below reflect that most recent reporting from CMS:

• The model saves money at scale: ACOs generated $2.5 billion in net savings relative to benchmarks, the largest since the program began, per CMS's updated results.
• Most participating ACOs earn payments: 75 percent of the 476 participating ACOs earned performance payments totaling $4.1 billion, per CMS.
• Reach is broad: The ACOs earning payments represented 80 percent of the 10.3 million beneficiaries assigned to an ACO that year, per CMS.
• Downside is real: 16 ACOs owed $20.3 million in shared losses, a reminder that in two-sided models risk cuts both ways.

CMS has also reported quality gains alongside the savings, including a rise in patients with controlled blood pressure (from 69.6 to 73.7 percent) and a drop in patients with poor hemoglobin A1c control (from 35.2 to 23.5 percent).

The through-line is consistent: the savings come from managing spending and quality together across an attributed population, not from any single billed service.

How MSSP Rules Change Each Year

Providers planning multi-year should know that the program's financial rules are not fixed.

CMS updates the Shared Savings Program regularly through annual rulemaking, most often in the yearly Physician Fee Schedule rule, and recent cycles have adjusted parameters such as track sharing rates, benchmark and savings-adjustment methodology, and the window an ACO can spend under a one-sided model before moving to two-sided risk.

The CY 2026 Physician Fee Schedule final rule, for example, finalized changes intended to move more ACOs into two-sided risk. Because these parameters shift, treat any specific rate or rule as current-year only.

Confirm the active requirements against the latest CMS Shared Savings Program guidance and final rule before making a participation or track decision, and check locality-specific payment amounts through the CMS Physician Fee Schedule Look-Up Tool.

Where Remote Patient Monitoring and CCM Fit in the Shared Savings Equation

For an ACO, the shared savings opportunity is tied directly to total cost of care, and total cost of care is driven heavily by avoidable acute utilization: emergency department visits, hospitalizations, and readmissions among high-risk patients.

Managing those patients well between visits is where the benchmark math is won or lost.

The clinical evidence supports the connection. In a recent study of 597 high-acuity Medicare beneficiaries enrolled in a technology-enabled remote patient monitoring (RPM) program, median annualized total cost of care fell from $25,956 to $11,792, a median reduction of $10,932 per patient, while emergency department visits declined 19.9 percent and inpatient hospitalizations fell 40.9 percent.

Remote patient monitoring gives your care team visibility into physiological trends between visits, so you can address a patient whose blood pressure has been climbing for weeks before the trend becomes a hospitalization.

Three care-management programs do the operational work behind those numbers, and each ties to its own workflow and documentation:

• Remote patient monitoring: Daily device readings sent to your care team surface deterioration early, so your clinicians can intervene before a manageable condition becomes an expensive acute event. See our overview of remote patient monitoring for how the workflow runs.
• Chronic care management: Structured, non-face-to-face coordination for patients with multiple chronic conditions keeps care plans active between appointments, which is where much of avoidable utilization originates. Our guide to chronic care management covers eligibility and workflow.
• Advanced primary care management: A bundled, non-time-based model for coordinating a full primary care panel, useful for ACOs standardizing management across attributed patients. See advanced primary care management for the details.

These programs also generate fee-for-service reimbursement while an ACO pursues shared savings, which is worth modeling alongside the savings opportunity. For how those payment structures compare, our breakdown of fee-for-service versus value-based care is a useful companion.

How KangarooHealth Helps ACOs Manage Total Cost of Care

At KangarooHealth, we run the between-visit remote patient monitoring and chronic care management that moves total cost of care for ACOs and provider groups, without adding headcount, so your team can focus on the clinical decisions.

Here is what the support looks like day to day:

• All-in-one program breadth: Our single platform covers remote patient monitoring, remote therapeutic monitoring, chronic care management, principal care management, advanced primary care management, and the CMS GUIDE model, across 50-plus conditions.
• US-based multilingual clinical team: Our nurses and clinicians monitor your patients under your own brand (white-label), at a nurse-to-patient ratio of roughly 1:125 to 1:150.
• Device-agnostic and cellular-first: We support more than 100 pairable FDA-cleared devices that work with no smartphone, internet, or Bluetooth required, which fits rural and elderly panels.
• Reimbursement-ready reporting: We track time and generate reimbursement-ready reports; claims are submitted by the provider, and reimbursement is payable to the provider, with full revenue cycle management available on request through our billing partners.
• Reported outcomes: Our programs are associated with a 48 percent reduction in adverse events (a reported outcome, not a guarantee) across more than 200,000 monitoring hours, according to our own data.
• Fast setup: Go-live typically takes under two weeks, with meaningful program results usually taking two to three months as enrollments and referrals ramp up.

Want to see how this maps to your attributed population and your track? Go-live typically takes under two weeks, so the next step is simple: schedule a demo with our team.

Frequently Asked Questions

Here are the questions provider organizations most often ask about the Shared Savings Program:

Is the Medicare Shared Savings Program the Same as an ACO?

No. An accountable care organization (ACO) is the provider entity; the Shared Savings Program is the CMS program that ACOs join to share in Medicare savings.

The Shared Savings Program is the largest and permanent ACO program, though CMS also runs other ACO models through its Innovation Center.

How Much Can an ACO Earn in Shared Savings?

The share depends on the track and level.

BASIC track ACOs can earn up to 40 percent of savings under one-sided levels and up to 50 percent under two-sided levels, while ENHANCED track ACOs can earn up to 75 percent, with total savings capped as a percentage of the benchmark and payment conditioned on meeting the quality standard.

Does the Shared Savings Program Have Downside Risk?

Yes, in the two-sided models.

BASIC Levels A and B are upside-only, so the ACO owes nothing back for losses, while BASIC Levels C through E and the full ENHANCED track are two-sided, meaning an ACO that overspends its benchmark owes CMS a share of the losses.

How Do RPM and CCM Support Shared Savings?

Remote patient monitoring and chronic care management reduce avoidable acute utilization, which lowers total cost of care, the metric shared savings is measured against.

Published research associates technology-enabled RPM with substantial reductions in total cost of care, emergency department visits, and hospitalizations among high-acuity Medicare beneficiaries.

Where Do I Confirm Current Program Rules and Rates?

CMS is the authoritative source. Confirm current-year program requirements and any payment parameters against the CMS Shared Savings Program pages and the CMS Physician Fee Schedule Look-Up Tool before making participation or track decisions.

Conclusion

The Medicare Shared Savings Program rewards provider organizations that can hold total cost of care below a CMS benchmark while meeting quality standards, and it pays a share of the savings that scales with the risk an ACO is willing to carry. The record $2.5 billion in net savings and $4.1 billion in performance payments show the model working at scale, but the payment turns on a hard operational reality: managing high-risk patients well in the weeks between visits, where avoidable utilization is either prevented or paid for.

At KangarooHealth, we support that work as a connected-care partner rather than a software vendor. Our US-based multilingual clinical team monitors your patients under your own brand, and our reporting is reimbursement-ready with claims payable to your organization. Go-live typically takes under two weeks across a device-agnostic, cellular-first platform. Your ACO can extend its reach into the between-visit gap without adding headcount.

Ready to model what between-visit care could mean for your benchmark, your attributed population, and your Shared Savings Program track? The fastest way to find out is to talk to an expert.

About the Author

Dr. Xiaoxu Kang is the CEO and Founder of KangarooHealth. Dr. Kang holds a PhD and completed medical training at Johns Hopkins Medicine and brings more than 20 years of experience in healthcare innovation, building remote-care technology that helps providers and ACOs manage patients between visits. Clinical and regulatory guidance in this article is drawn from CMS program data and rules and from named peer-reviewed research. Last updated: October 2026.

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This article is for general informational purposes only and does not constitute medical, legal, or billing advice. Medicare program rules and payment rates change annually and vary by locality; verify current-year requirements against the CMS Physician Fee Schedule and the CMS Shared Savings Program pages. Consult qualified professionals before making clinical or reimbursement decisions.