The biggest piece of ACO REACH news this year is the end of the model itself: REACH concludes on December 31, 2026, and the Long-term Enhanced ACO Design (LEAD) Model takes its place on January 1, 2027.

That puts two clocks on ACO leadership at once: the first is REACH’s final performance year, including the SDoH data collection tied to your 2026 quality score. The second is how to build toward LEAD’s alignment requirements before the model even starts.

ACOs are straining to solve both problems around a single program timeline. Fragmented workflows, disorganized survey data, and unclear ownership of the transition all become real risks once the two models overlap.

Mabel supports ACOs through exactly this dual-track period, particularly the SDoH survey collection and reporting side of REACH’s close-out. Here’s what’s changing, what CMS still requires before sunset, and how organizations are approaching LEAD.

Why REACH Is Ending, and What LEAD Changes

REACH is closing on real financial results, not a failed experiment. Multiple legal and industry analyses confirm the December 31, 2026 sunset, with no further performance years planned.

REACH ACOs generated $2.5 billion in gross savings and returned $988.3 million in net savings in PY2024, a 6.7% net savings rate and a 24% jump in gross savings per beneficiary per month over 2023, per reporting on CMS’s PY2024 results. The caveat: CMS’s own PY2023 evaluation, using a control-group methodology rather than prospective benchmarks, found net Medicare spending increased once shared savings and incentive payments were factored in, a tension still feeding debate over how REACH’s performance should be read.

The footprint has also been shrinking. CMS reports just 74 ACOs and 1.7 million beneficiaries for 2026, down from 115 ACOs and roughly 2.5 million in PY2024, against MSSP’s 511 ACOs and 12.6 million beneficiaries, a scale REACH never approached. That gap is a large part of why CMS is consolidating around one long-term design instead of running REACH alongside a much larger program indefinitely.

LEAD isn’t a renewal. It’s a differently structured successor, and REACH participants must actively apply. It’s a 10-year model (2027–2036) using a fixed baseline for the full period rather than periodic rebasing. Standard ACOs need 5,000 aligned beneficiaries by PY1, with lower thresholds of 800 for High Needs ACOs and 1,000 for Newly Entering ACOs, per CMS’s LEAD Model FAQ. Alignment runs two tracks: claims-based, from utilization patterns, and voluntary, where a beneficiary actively selects an affiliated provider. The RFA deadline for the first LEAD performance year was May 17, 2026.

LEAD also brings mechanisms REACH never had. CMS-Administered Risk Arrangements (CARA) let ACOs enter episode-based risk arrangements with specialists, including a falls-prevention episode program, a specialist-engagement structure absent from REACH’s ACO-only risk model, per Bass, Berry & Sims’s analysis. Beneficiary-facing incentives arrive too: Part B cost-sharing support immediately, and a Part D premium buy-down starting in 2029. A Medicaid integration track for dually eligible beneficiaries is also in motion, with CMS running a planning phase from March 2026 through December 2027 to select two states for ACO-Medicaid partnership frameworks, a detail most REACH-to-LEAD comparisons only mention in passing.

What’s Still Owed Before December 31, 2026

Not all of this year’s REACH news is about LEAD. ACOs still owe CMS PY2026 SDoH data tied directly to the year’s quality score. CMS set the ACO REACH Quality Withhold at 5% of the Financial Benchmark, with up to 5 percentage points of the resulting Quality Score tied to beneficiary-reported SDoH data, collected via one of three approved instruments (AHC HRSN, the North Carolina SDoH Screening Tool, or NACHC’s PRAPARE), per CMS’s PY2026 quality measurement methodology.

Two operational details matter. Only data collected during PY2026 counts; late collection doesn’t retroactively help. And reporting is voluntary on the beneficiary’s end. ACOs can’t require an answer, which puts the burden on outreach design rather than mandate, with responsibility sitting at the ACO level rather than per-provider.

Building Toward LEAD Alignment

Applying is only step one. ACOs submitting an RFA response still need a plan for reaching their minimum aligned count by PY1, and that work has to start before the model launches: segmenting beneficiaries into claims-eligible versus those needing voluntary alignment, coordinating outreach messaging across every affiliated location, and running campaigns across mail, email, and in-clinic touchpoints.

The challenge is scale. Generic mail and email from an unfamiliar ACO name tends to underperform; beneficiaries respond better to communication from a provider they already know. That’s the gap Mabel’s voluntary alignment work targets: provider-based direct mail sent under a beneficiary’s own doctor’s name, which Mabel has found drives the highest response of any tactic it runs. Automating that outreach, plus response processing and CMS-formatted alignment tracking, matters heading into LEAD’s first performance year.

Part of the same infrastructure is Beneficiary Notification Letters, the compliance notices CMS requires for newly aligned members. Automating scheduling, delivery tracking, and address validation now builds capacity for the alignment volume LEAD will demand.

Where SDoH Collection Breaks Down

The bottleneck in REACH’s final year usually isn’t willingness. It’s fragmentation. ACOs spanning multiple EMRs often can’t pull a clean, standardized set for CMS submission, since each practice captures demographic and SDoH fields differently, or not at all. Standardizing on a single approved tool network-wide, running practice-specific online surveys where EMR extraction isn’t feasible, and tracking completion by provider in real time all surface gaps while there’s still runway to close them.

Treat PY2026 SDoH Reporting as Closeout, Not Routine 

There is no subsequent cycle in which to recover missed data, which changes the planning approach. 

Three practices reduce the risk of gaps at submission: identifying beneficiaries who have not completed a screening, selecting each subgroup’s collection channel based on prior response history, and consolidating responses in a single system rather than provider-level spreadsheets. Documentation of when and how each beneficiary’s SDoH data was collected also carries audit weight, as CMS may request support for a REACH ACO’s reported quality performance.

Mabel in Practice

A high-needs REACH participant with roughly 1,000 aligned beneficiaries across 20-plus providers on different EMRs was struggling to consolidate HEDR data; only two practices could export usable data on their own. Running practice-specific online surveys and tracking completion by provider through Mabel, the ACO captured more than 90% of its PY2023 HEDR data within two weeks and stayed on track to recover a $100,000-plus adjustment payment, per Mabel’s HEDR case study. Fragmented EMRs don’t have to mean fragmented reporting, a lesson that carries directly into PY2026.

A large REACH participant managing 100,000-plus eligible fee-for-service beneficiaries had only about 40% claims-aligned, with a manual voluntary alignment process producing rejection rates as high as 50% from data-entry errors. Moving campaign execution, response processing, and alignment tracking to Mabel produced a 30% increase in net-new alignments over 12 months, with real-time visibility into which channels and providers drove results, per Mabel’s voluntary alignment case study. For ACOs building toward LEAD’s beneficiary minimums, that’s scale without added headcount.

Next Steps

Closing REACH means getting PY2026 SDoH data collected, standardized, and submission-ready before December 31, 2026. Preparing for LEAD, for ACOs choosing to apply, means building alignment and notification infrastructure well before PY1 begins.

Mabel’s role here is specific: helping ACOs run SDoH survey collection and reporting across fragmented provider networks so PY2026 data is complete and submission-ready before the window closes. If your team is still consolidating SDoH data across multiple EMRs with sunset approaching, it’s worth reaching out to Mabel to see how that process could run with less manual reconciliation this final performance year.

Frequently Asked Questions

Does every ACO REACH participant have to apply for the LEAD Model?

No. CMS built LEAD’s applicant pool to extend well beyond current REACH participants, explicitly anticipating Medicare fee-for-service providers new to accountable care and organizations serving underserved populations, including those with a high proportion of dually eligible beneficiaries, Federally Qualified Health Centers, and Rural Health Clinics, per CMS’s LEAD model overview.

Part of the decision comes down to risk tolerance. LEAD offers a Global track (up to 100% risk, a sliding 1.75% to 3% discount) and a Professional track (capped at 50% risk, no discount, a four-year commitment before switching), per Benesch Law’s analysis of the model.

Organizations that decide not to apply face no special CMS-imposed penalty beyond exiting this particular model; REACH concludes on December 31, 2026, for every participant regardless of their LEAD decision.

What happens if an ACO misses the May 17, 2026 LEAD application deadline?

Missing the window doesn’t necessarily mean waiting a full decade. CMS’s LEAD Model FAQ references future application cohorts beyond the first, though specific dates for a second cycle haven’t been published. Organizations that miss the initial deadline should confirm timing directly with CMS.

It also helps to clarify which deadline applies. CMS’s LEAD Model FAQ frames May 17, 2026 partly as a Letter of Interest step for future cohorts, not a full Request for Applications submission for the first performance year. Read the specific deadline language for your situation rather than assume every May 17 reference means the same thing.

For an ACO weighing whether to rush an application or wait for a later cohort, the practical tradeoff is time. A delayed start allows more runway to build infrastructure, but means operating without LEAD’s benchmark and payment structure during the gap. CMS hasn’t published how a later cohort’s timeline would compare to the one starting January 1, 2027.

Has ACO REACH always required SDoH data collection for the health equity adjustment?

No. Through Performance Year 2023, the health equity reporting requirement covered only demographic elements such as race, ethnicity, and preferred language.

CMS expanded it starting in Performance Year 2024 to add SDoH data and additional demographic categories, including sexual orientation and gender identity, per an analysis of CMS’s health equity reporting requirements.

The financial weight tied to that data has shifted too. Under the framework CMS used in earlier plan years, the Health Equity Data Reporting adjustment could contribute up to 10 percentage points against a 2% quality withhold, a different scale than the current PY2026 mechanics described above, per the same analysis.

How is the SDoH/HEDR requirement different from the Beneficiary Notification Letter requirement?

They affect different parts of an ACO’s financial picture.

SDoH data collection feeds into the Quality Score and Quality Withhold calculation set out in CMS’s PY2026 quality measurement methodology report, while Beneficiary Notification Letters are a standalone compliance obligation with no bearing on that withhold.

The two also run on different clocks. SDoH data collection follows a defined annual performance-year window, while BNLs go out continuously, triggered by each beneficiary’s individual alignment date rather than tied to any fixed annual cycle.

That distinction matters for internal recordkeeping. An ACO can be fully current on BNL delivery for every newly aligned beneficiary and still fall short on SDoH reporting if survey outreach hasn’t reached enough of the broader population, so tracking both requirements on a single dashboard without separating their deadlines and target populations is a common source of confusion.

Will LEAD use the same Beneficiary Notification Letter process as ACO REACH?

CMS has not published detailed beneficiary notification mechanics for LEAD with the same specificity as its alignment rules, per CMS’s Innovation Insight announcement.

ACOs evaluating LEAD should confirm current requirements in the Request for Applications instead of assuming REACH’s process carries over unchanged. What CMS has said is that LEAD builds on the Innovation Center’s existing accountable care work, not a blank-slate redesign, which suggests some continuity with REACH’s compliance framework even where exact notification mechanics haven’t been spelled out yet.

How much of a LEAD ACO’s beneficiary minimum has to come from claims-based alignment?

The claims-based share varies by track, per CMS’s LEAD Model FAQ.

Standard ACOs need 3,000 claims-based beneficiaries in a base year toward their 5,000-beneficiary Performance Year 1 minimum, High Needs ACOs need 500 toward 800, and Newly Entering ACOs need 600 toward 1,000. The remainder can come through voluntary alignment.

These figures are a starting point, not a fixed ceiling. CMS’s LEAD Model FAQ notes that minimum aligned-beneficiary thresholds will grow gradually over the course of the model’s ten-year run, so a standard ACO that clears 5,000 in Performance Year 1 should expect the bar to move in later years.