ACO REACH Ends in 2026: What the LEAD Model Means for Practices

Updated October 2026. Written by Matteo Grassi, clinical psychologist and cofounder of HANA Health.

The LEAD model is a voluntary, ten year Medicare accountable care model from the CMS Innovation Center. It starts January 1, 2027, the day after ACO REACH ends, and runs through December 31, 2036. It lets practices share savings and losses on total Medicare cost of care, with monthly prospective payments and benchmarks that won't be rebased.

I read every payment model through one question: who actually reaches the patient between visits? LEAD is built around that question, so it's worth understanding before your next planning cycle.

Key facts

• LEAD runs 10 years. It covers performance years 2027 to 2036, the longest model period CMS has ever tested, per the CMS LEAD model page.
• ACO REACH ends December 31, 2026. It had 74 ACOs serving about 1.7 million people with Traditional Medicare in 2026, per the CMS 2026 ACO participation highlights.
• 14.3 million Medicare beneficiaries were in accountable care as of January 2026, including 12.6 million in 511 Shared Savings Program ACOs, per the same CMS fact sheet.
• Two risk options. Global risk shares up to 100% of savings and losses. Professional risk shares up to 50%, per the LEAD overview.
• Standard ACOs need 5,000 aligned beneficiaries. Lower minimums apply to newly entering ACOs and to ACOs with 40% or more High Needs patients, per the LEAD technical FAQ.
• Quality is 7 measures. Four claims based measures, one CAHPS patient experience survey and two eCQMs, with 3% of the benchmark at risk for quality, per the same FAQ.
• The first application window closed May 17, 2026. CMS expects future cohorts but hasn't announced details, per the LEAD request for applications.

What is the LEAD model?

LEAD stands for Long-term Enhanced ACO Design. It's CMS's newest accountable care model, designed as the successor to ACO REACH. An ACO is a group of practices and other providers that take responsibility for the cost and quality of care for a defined group of Original Medicare patients.

CMS says LEAD aims to attract providers who haven't joined ACOs before, including smaller, independent and rural practices, and to serve patients with complex needs better. The model uses whole Tax Identification Number (TIN) participation, the same approach the Shared Savings Program uses, so a practice joins as a billing entity rather than clinician by clinician.

The big design choice is time. A ten year period with no rebasing means a practice that lowers costs doesn't see its benchmark reset against its own success. CMS describes this as a way to avoid the "ratchet effect" that penalized successful ACOs in earlier models. It's an intention, and it's untested at this length, so treat it as a stated goal rather than a proven result.

What happens when ACO REACH ends in December 2026?

ACO REACH closes to new applications and ends on December 31, 2026, after four performance years that began in 2023. Organizations that were in REACH for 2026 could file an abbreviated LEAD application, but acceptance wasn't guaranteed, per the LEAD technical FAQ.

Here's the timeline that matters right now:

1. May 17, 2026: first LEAD application window closed.
2. September 8, 2026: deadline to drop Participant TINs and to resolve any overlap with a Shared Savings Program ACO.
3. September 15 to December 31, 2026: optional implementation period. No payments and no financial risk. ACOs use it for voluntary alignment so they can meet minimums on day one.
4. January 1, 2027: performance year 2027 begins.

A TIN can't sit in LEAD and the Shared Savings Program at the same time. If your practice is in a REACH ACO today, ask the ACO which path it chose for 2027, because your participation follows the ACO's decision.

Who can join LEAD, and how big does an ACO need to be?

An ACO needs at least 5,000 aligned Original Medicare beneficiaries in a performance year, with 3,000 aligned by claims in at least one base year. The minimums drop for two groups, and they grow over time. These are the published figures from CMS's RFA webinar slides:

• Standard ACO: 5,000 in every performance year.
• Newly entering ACO: 1,000 in year one, then 2,000, 3,000 and 4,000, reaching 5,000 in year five.
• High Needs ACO (40% or more High Needs beneficiaries, plus required care capabilities): 800 in year one, rising to 1,600 from year five.

A newly entering ACO has no prior Medicare ACO performance, fewer than 40% of its TINs in a Medicare ACO in the past five years, and fewer than 50% of its providers in one. CMS also lets an ACO that falls up to 10% short use one of two alignment buffers.

For a single practice, the practical point is that you'll almost always join through an ACO rather than alone. A group under 5,000 attributed patients needs a partner or a lower minimum.

How do the risk options and payments work in LEAD?

LEAD offers two risk options. Global risk lets an ACO keep up to 100% of savings and owe up to 100% of losses against its benchmark. Professional risk caps both at 50%. LEAD also offers prospective monthly payment options such as primary care capitation, which can give practices cash flow before savings are settled.

LEAD also adds tools aimed at patients. Participants can choose Part B cost sharing support and, by 2029, a Part D premium buy down, both described on the CMS LEAD page. An ACO can also use CMS Administered Risk Arrangements to set up episode based risk deals with specialists.

Two things CMS hasn't promised: any particular amount of savings, and any particular payment per patient for your practice. What you earn depends on how your ACO splits money with its participants, so read that agreement closely.

Which quality measures will LEAD ACOs be judged on?

LEAD scores seven measures and puts 3% of an ACO's benchmark at risk for quality. The ACO can earn it back through performance, plus a Prevention and Quality Plan that every ACO must develop starting in 2027. This list comes from CMS's ACO model comparison:

• Four claims based measures: all cause unplanned admissions for older adults with multiple chronic conditions, risk standardized all condition readmissions, days at home for patients with complex chronic conditions, and timely follow up after acute events for certain chronic conditions.
• One patient survey: CAHPS patient experience.
• Two eCQMs: Diabetes Glycemic Status Assessment greater than 9%, and Controlling High Blood Pressure.

The two eCQMs phase in. Reporting is optional in 2027 and 2028, with bonus points for ACOs that report. They're scored on reporting in 2029 and 2030, and move to pay for performance in 2031. The claims based measures count from the start.

How is LEAD different from the Shared Savings Program?

LEAD is a time limited Innovation Center model, while the Shared Savings Program is a permanent program built on five year agreement periods. LEAD adds prospective capitation and episode arrangements with specialists. The Shared Savings Program is much larger today, with 511 ACOs and 12.6 million assigned beneficiaries in 2026, per CMS's fast facts.

CMS's own numbers show how much room is left. Only 45% of Original Medicare beneficiaries were aligned to the Shared Savings Program or ACO REACH as of June 2025, according to the LEAD request for applications. CMS says bringing in practices that haven't joined ACOs is a primary goal of LEAD.

What this means for your practice

If you're in a REACH ACO, confirm in writing whether it's moving to LEAD, which risk option it chose, and how voluntary alignment will work. The implementation period is the cheapest time to build outreach habits, because no beneficiaries are formally aligned and no one is at financial risk.

If you're not in an ACO, you've missed the first window but not the model. CMS expects more cohorts, though it hasn't announced dates, so subscribe to the LEAD listserv and start reading ACO agreements now.

Either way, quality measures like blood pressure control and timely follow up depend on reaching patients between visits. An earlier post on post discharge outreach covers why that gap is hard to close. At HANA, we build phone based patient outreach that practices use for care management programs, described on the HANA Remote page. If you want the technical side, the HANA documentation explains how voice agents connect to clinical workflows.

Frequently asked questions

Is LEAD replacing ACO REACH for every REACH participant?

No. LEAD is the intended successor, but participation isn't automatic. REACH participants could submit an abbreviated application, and CMS evaluated all applications, including abbreviated ones, for quality, financial stability and operations.

Can a small practice join LEAD without joining an ACO?

Not on its own. Participants in LEAD are ACOs, which are made up of Participant TINs and Preferred Providers. A small practice would join as a Participant TIN inside an ACO that meets the alignment minimum.

Will my patients lose their Medicare choices if I join?

No. LEAD is for people in Original Medicare, and CMS says beneficiaries keep all Original Medicare benefits. Patients also keep the ability to opt out of data sharing, which the RFA describes.

When will CMS announce the two Medicaid partner states?

CMS hasn't published the states yet. Its planning phase for the ACO Medicaid partnership framework runs from March 2026 through December 2027, per the CMS LEAD page.

Does LEAD change how I bill CCM or TCM?

CMS hasn't announced any change to those codes through LEAD. Check your ACO agreement and your MAC, because model waivers and payment arrangements can affect how revenue is shared.

Sources

1. CMS, LEAD (Long-term Enhanced ACO Design) Model, 2026.
2. CMS, LEAD Model Overview, 2026.
3. CMS, LEAD Model Request for Applications, revised April 15, 2026.
4. CMS, LEAD Model Frequently Asked Questions (technical), August 17, 2026.
5. CMS, LEAD Request for Applications Webinar slides, April 2026.
6. CMS, ACO Comparison: LEAD, ACO REACH, and Medicare Shared Savings Program, 2026.
7. CMS, 2026 Medicare Accountable Care Organization Initiatives Participation Highlights, February 4, 2026.
8. CMS, Shared Savings Program Fast Facts as of January 1, 2026, 2026.

This article is educational and isn't billing, coding, clinical or legal advice. Check current CMS guidance and your MAC before you bill. If you want to talk through patient outreach for your ACO or practice, book a discovery call.