CMS's WISeR Model Is Live: What 511 MSSP ACOs Must Do Right Now to Protect Shared Savings

By Jay Chowdappa, MD, co-founder and CEO, Zynix AI · Updated October 6, 2026

Key takeaways

CMS's WISeR (Wasteful and Inappropriate Service Reduction) model requires prior authorization, or pre-payment review, for 13 groups of services in Original Medicare in six states from 2026 through 2031. ACOs in those states protect shared savings by auditing exposure, documenting medical necessity before requests go out, tracking every request and appeal, and building complete clinical records.

• WISeR runs from January 1, 2026 to December 31, 2031 in New Jersey, Ohio, Oklahoma, Texas, Arizona and Washington, applies to Original Medicare, not Medicare Advantage, and as of October 2026 CMS had not added states or services.
• Reviewers aim to decide standard requests within 3 calendar days and expedited ones within 2, and a licensed clinician must confirm every non-affirmation.
• The technology companies running the reviews are paid a share of the savings tied to denials, which is why clean documentation before submission matters.
• Since July 2026, clinicians who submit at least 10 requests and meet a minimum approval rate can earn an exemption from WISeR review for at least a year.
• The 2026 MSSP year adds pressure of its own: 511 ACOs, a larger APP Plus measure set and no health equity adjustment to quality scores.

On January 5, 2026, a quiet but consequential shift happened in Medicare fee-for-service. That day, under CMS's WISeR (Wasteful and Inappropriate Service Reduction) model, which took effect January 1 in six states, the technology companies running the model began accepting prior authorization requests for services rendered on or after January 15 — and with them, AI-supported prior authorization arrived in Traditional Medicare. If you run an ACO, MSO, or value-based practice, you need to understand what this means for your shared savings trajectory before performance year 2026 closes on December 31.

The short version: CMS is using artificial intelligence to screen — and in some cases deny — Medicare FFS procedures before they're performed. The vendors operating these AI reviews are paid a share of the savings tied to the services their reviews deny. That incentive structure, combined with a three-day decision clock, creates a dynamic that will hit the revenue side of every participating organization in these six states, whether they see it coming or not.

What WISeR Actually Does — And What It Doesn't Change

Let's be precise. The WISeR model does not alter Medicare's coverage or payment rules. If a service is medically necessary and covered under existing CMS policy, it still gets reimbursed. What changes is the gate: providers in New Jersey, Ohio, Oklahoma, Texas, Arizona, and Washington must now obtain prior authorization before delivering select items and services, or accept pre-payment medical review of the claim instead.

As of the July 24, 2026 update of CMS's operational guide, the scope covers 13 groups of items and services, including:

• Skin and tissue substitutes (wound care grafts)
• Electrical nerve stimulator implants
• Knee arthroscopy for knee osteoarthritis
• Cervical fusion, epidural steroid injections and percutaneous vertebral augmentation
• Vagus, phrenic, sacral and hypoglossal nerve stimulation, incontinence control devices, induced lesions of nerve tracts, and diagnosis and treatment of impotence

The AI layer operates alongside human clinical review, with determinations expected within 3 calendar days (2 days for expedited requests). Contractors use existing Medicare coverage criteria — but whether a given case clears those criteria now runs through AI and machine learning tools, not just a human reviewer reading a chart fax, although every non-affirmation must still be confirmed by an appropriately licensed clinician.

The model runs from January 1, 2026 through December 31, 2031 — six full performance years. This is not a pilot you can wait out.

One relief valve arrived mid-year. Since July 2026, CMS and the WISeR participants have run an exemption program: an individual clinician who submits at least 10 prior authorization requests for WISeR services during an assessment period and meets a minimum affirmation rate can be exempted from prior authorization and pre-payment review for all WISeR services for at least a year. Exemptions are granted per clinician (NPI), not per organization, which makes clean, consistent submissions a practice-wide discipline.

The Incentive Structure Problem Every CFO Should Read Twice

Here is the detail most WISeR coverage buries in paragraph seven: the vendors running AI-powered reviews are paid a share of the savings attributable to the services their reviews deny.

CMS has built in safeguards: a licensed clinician must confirm every non-affirmation, participants are paid only once per beneficiary however many times a request is resubmitted, and payments for denials overturned on appeal are withheld or recouped. But from a financial engineering standpoint, paying reviewers from denial savings and asking them for accuracy remain structurally in tension. An AI system optimizing for cost reduction, operated by a contractor with a revenue-sharing arrangement on denials, will generate approval friction even when individual denials are technically defensible.

For ACOs carrying downside risk under the MSSP ENHANCED track or BASIC Level E, this matters in two directions. First, services rendered in WISeR states may face new pre-authorization delays that push utilization into denial territory. Second, services that should be approved but are deferred past the clinical window create documentation and appeals burdens that most practice-level care teams are not staffed to absorb.

The net effect: organizations with clean documentation workflows, tight coding accuracy, and proactive care management will clear the AI gate faster. Organizations relying on reactive, paper-based processes will see a material increase in denial rates — and shared savings impact will follow.

The 2026 MSSP Picture: 511 ACOs, Expanded Reporting, and Prepaid Savings

WISeR doesn't arrive in a vacuum. It lands on top of a 2026 MSSP environment that is already more demanding than 2025's across multiple dimensions.

CMS approved 134 applications for performance year 2026, 72 from new ACOs and 62 from renewing or reentering ACOs, bringing total MSSP participation to 511 ACOs — up from 476 last year. Alongside that growth, CMS expanded quality reporting requirements: the APP Plus quality measure set ACOs report grows to 8 quality measures in 2026 and 9 in 2027, with a tenth, Adult Immunization Status, phased in from 2028 at the earliest, after CMS dropped the planned social drivers of health screening measure. The health equity adjustment was simultaneously removed from ACO quality scoring, eliminating a buffer some organizations had been quietly relying on to cushion performance gaps.

There is one structural bright spot: CMS is distributing the first Prepaid Shared Savings (PSS) payments in PY 2026. Eligible ACOs receive quarterly advance payments on projected shared savings — funding they can deploy into care infrastructure, staffing, and direct beneficiary services before year-end reconciliation. But PSS is only useful to organizations already on a shared savings trajectory. If your AWV completion, gap closure rates, and quality scores are lagging, the advance doesn't help — and you may still owe back what you received.

Where Documentation Depth Becomes a Prior Auth Defense

The WISeR model's core assumption is that a significant portion of targeted services are being ordered without rigorous clinical substantiation. That's probably accurate across the industry. But it's not uniformly true — and the variance in documentation quality creates predictable winners and losers when AI reviewers start scoring prior auth requests.

Organizations running structured care management programs with high Annual Wellness Visit (AWV) completion rates carry a different risk profile than those relying on opportunistic gap closure. Consider the patterns visible across Zynix-supported organizations:

• PBACO, one of the nation's largest risk-bearing ACOs, partnered with Zynix in April 2026 on AI-driven voice and SMS outreach for Annual Wellness Visit engagement and post-discharge follow-up across its provider network. AWVs don't trigger WISeR review, but the longitudinal documentation infrastructure built around them does. Patients with structured, annual clinical records are stronger prior auth candidates because their medical history is richer, better-coded, and readily reviewable by AI systems.
• eternalHealth, a Medicare Advantage plan in Massachusetts and Arizona, has used Zynix's outreach and care management workflows since January 2026. WISeR does not apply to Medicare Advantage members, but the same logic holds in any prior authorization review: a proactive care management engine changes which procedures get ordered, in what clinical context, and with what documentation trail attached. That changes the prior auth outcome before the review even begins.

The pattern is consistent: organizations that close care gaps proactively generate the documentation depth that AI prior auth reviewers require. Organizations that don't are about to find out how expensive that gap is.

You can see how Zynix deploys AI agents for ACO and MSO care gap workflows at zynix.ai/audience-segments/acos-msos, or explore the outreach and documentation agents operating at scale at zynix.ai/agents.

The Operational Playbook: Four Actions for WISeR States

1. Audit your WISeR-adjacent service volume

Pull claims data for skin and tissue substitute codes, nerve stimulator implant codes, knee arthroscopy codes and the other WISeR service codes across your attributed population in the six WISeR states. Understand the volume, the ordering providers, and the existing documentation patterns before the first denial arrives.

2. Close the gap between clinical knowledge and EHR documentation

AI reviewers in the WISeR system are matching orders against existing Medicare coverage policies. The gap between what a clinician knows about medical necessity and what appears in the EHR note is where denials are generated. That gap needs to close before the prior auth request is submitted — not after it's denied.

3. Build a denial tracking and appeals workflow before year-end

The three-day WISeR decision window is tight. Organizations without dedicated prior auth tracking will lose visibility into pending requests, miss appeal windows, and absorb denials as permanent revenue losses. Administrative appeal rights exist on paper — capturing them operationally requires purpose-built workflow infrastructure.

4. Use AWV and care gap data as a proactive prior auth defense

Prior auth reviewers evaluate clinical context, not just procedure orders. Patients with documented, structured care histories are stronger approval candidates than those whose only Medicare encounters are acute or specialty visits. AWV completion and care gap closure aren't just quality metrics in 2026 — they are prior auth defense mechanisms.

What Comes Next: LEAD, APP+, and the Longer Arc

WISeR is the first move in a sustained CMS push to introduce AI-mediated accountability across Medicare FFS. The LEAD (Long-term Enhanced ACO Design) model launches January 1, 2027, at the conclusion of ACO REACH; in September 2026, CMS named 79 ACOs in LEAD's optional implementation period and said it is working with well over 100 ACOs preparing for 2027. The direction of travel points to a future where accountable care and prior authorization aren't parallel workflows — they're integrated into a single value determination infrastructure.

Organizations positioned to absorb this shift are those building AI-native care management operations now. Not because it's strategically elegant — but because the operational infrastructure required to navigate WISeR in 2026 is identical to the infrastructure required to excel in LEAD in 2027. They are not separate workstreams. They are the same workstream, running two years apart.

Organizations still running reactive care management in Q4 2026 will enter LEAD negotiations with a documentation deficit, a WISeR denial exposure, and a PSS advance they may have to repay. Organizations that used 2026 to close care gaps systematically will enter with shared savings, clean longitudinal records, and prior auth workflows that AI reviewers approve on first submission.

That gap is not closing on its own.

Frequently asked questions

What is the CMS WISeR model?

WISeR (Wasteful and Inappropriate Service Reduction) is a CMS Innovation Center model that adds prior authorization, or pre-payment medical review, for selected items and services in Original Medicare from January 1, 2026 through December 31, 2031. Six technology companies run the reviews with AI tools, licensed clinicians decide every non-affirmation, and Medicare coverage and payment rules themselves do not change.

Which states are in WISeR, and does it apply to ACO patients?

WISeR covers New Jersey, Ohio, Oklahoma, Texas, Arizona and Washington, and CMS had not added states as of October 2026. It applies only to Original Medicare; Medicare Advantage and Railroad Medicare beneficiaries are excluded. Patients aligned to Medicare Shared Savings Program ACOs are in Original Medicare, so their WISeR services in those states need prior authorization or face pre-payment review.

Which services need prior authorization under WISeR?

As of CMS's July 2026 operational guide, 13 groups: skin substitutes for lower-extremity wounds, electrical nerve stimulators, knee arthroscopy for osteoarthritis, cervical fusion, epidural steroid injections, percutaneous vertebral augmentation, vagus, phrenic, sacral and hypoglossal nerve stimulation, incontinence control devices, induced lesions of nerve tracts, and diagnosis and treatment of impotence. Deep brain stimulation and lumbar decompression remain delayed.

How can a clinician get exempted from WISeR prior authorization?

Since July 2026, WISeR participants grant exemptions to individual clinicians, by NPI, who submit at least 10 prior authorization requests for WISeR services in an assessment period and meet a minimum affirmation rate. Exempted clinicians skip prior authorization and pre-payment review for all WISeR services for at least a year, subject to a small number of follow-up documentation requests. Tracking every request and its outcome is the starting point.

What happens if a WISeR prior authorization request is denied?

A non-affirmed request can be resubmitted with more documentation as many times as needed, and the requester can ask for a peer-to-peer review with a clinician who has relevant specialty expertise. If a service is delivered and the claim is then denied, all standard Medicare appeal rights apply, and the reviewer's payment for a denial that is overturned on appeal is withheld or recouped.

Related reading

• CMS WISeR Is Live in 6 States: What the AI Prior Auth Pilot Means for Your Revenue Cycle — and How to Reach Gold Card Status Before June 2026
• Why ACOs Are Losing Millions to Claim Denials—And How Agentic AI Fixes the Revenue Cycle
• ACO LEAD Model: Why 2027 Will Reward ACOs That Can Execute Between Visits

Source notes

CMS: WISeR (Wasteful and Inappropriate Service Reduction) Model. https://www.cms.gov/priorities/innovation/innovation-models/wiser

CMS: WISeR Model Provider and Supplier Operational Guide, Version 7.0 (July 24, 2026). https://www.cms.gov/priorities/innovation/files/wiser-provider-supplier-guide.pdf

CMS: WISeR Model Payment Methodology. https://www.cms.gov/priorities/innovation/files/wiser-payment-methodology.pdf

CMS: 2026 Medicare Accountable Care Organization Initiatives Participation Highlights (fact sheet, February 4, 2026). https://www.cms.gov/newsroom/fact-sheets/2026-medicare-accountable-care-organization-initiatives-participation-highlights

CMS: Calendar Year (CY) 2026 Medicare Physician Fee Schedule Final Rule (CMS-1832-F), Medicare Shared Savings Program Changes (fact sheet). https://www.cms.gov/newsroom/fact-sheets/calendar-year-cy-2026-medicare-physician-fee-schedule-final-rule-cms-1832-f-medicare-shared-savings

CMS: Prepaid Shared Savings Guidance, Version 2 (April 2026). https://www.cms.gov/files/document/prepaid-shared-savings-guidance.pdf

CMS: LEAD (Long-term Enhanced ACO Design) Model. https://www.cms.gov/priorities/innovation/innovation-models/lead

CMS: LEAD Model Implementation Period Participant List (September 21, 2026). https://www.cms.gov/priorities/innovation/files/lead-imp-participant-list.pdf

About the author

Jay Chowdappa, MD is co-founder and CEO of Zynix AI. He is a physician, and ACOs led by him generated $300M+ in shared savings before he started Zynix AI to help care teams follow through on what their data already shows.