The Transition Is Over
As of January 1, 2026, the CMS-HCC V28 risk adjustment model is 100% in effect. No more blended transition periods. No more running V24 and V28 side by side. Every diagnosis code, every risk score, every payment calculation now runs entirely through V28. For health plans still operating as if the transition is ongoing, the window has closed.
V28 represents the most significant restructuring of the CMS-HCC model in years. It dropped 2,000+ ICD-10 codes that previously mapped to HCCs. It eliminated several HCC categories entirely. It recalibrated coefficients to reduce the outsized impact of certain high-value diagnoses that had been targeted by aggressive coding programs. The net effect: plans that relied on volume-based code capture will see direct, measurable revenue impact unless they change their approach.
What Changed and Why It Matters
V28 wasn’t a technical update. It was a policy signal. CMS designed it to reduce overpayments driven by coding intensity rather than genuine patient complexity. The model penalizes the very behaviors that many retrospective programs were built around: finding as many codes as possible, regardless of clinical relevance or documentation quality.
Conditions like vascular disease, specified heart arrhythmias, and certain diabetes complications saw meaningful coefficient changes. Some codes that generated significant revenue under V24 now contribute far less to risk scores. Plans that haven’t recalibrated their coding priorities are chasing codes that no longer move the needle while missing conditions that now carry greater weight.
V28 also increased the value of conditions tied to genuine clinical complexity. Well-documented, encounter-linked diagnoses for conditions like chronic kidney disease, heart failure, and major depressive disorder now carry more weight. The model rewards accuracy and penalizes inflation. That’s not speculation. It’s the design intent CMS published alongside the final rule. Plans that have invested in documentation quality and clinical accuracy are positioned to perform better under V28 than they did under V24.
The Operational Impact
For coding teams, V28 means retraining across the board. Coders need updated code-to-HCC mapping tables, refreshed clinical guidelines, and new prioritization logic for chart reviews. Conditions they used to chase may no longer be worth the effort. Conditions they previously overlooked may now be high priority. Without updated tools and training materials, coders are working from an outdated playbook and wasting effort on codes that no longer generate meaningful risk score impact.
For compliance teams, V28 increases the stakes on documentation quality. With fewer codes mapping to HCCs, every submitted code carries more weight. A single unsupported diagnosis has a proportionally larger impact on audit outcomes. The margin for error has shrunk, and CMS’s population-level coding pattern analysis makes it easier than ever to spot anomalies across a plan’s entire book of business.
For finance teams, V28 changes revenue forecasting. Plans need to model RAF score impacts under the new coefficients, identify where revenue will shift, and adjust projections. Running 2026 financial models on 2025 transition-era assumptions will produce unreliable forecasts. CFOs who haven’t updated their revenue models are making decisions based on numbers that no longer reflect reality.
What Winning Looks Like Now
The plans that thrive under V28 will be the ones that stopped treating risk adjustment as a volume game before CMS forced them to. They’re investing in documentation quality at the point of care. They’re running two-way retrospective reviews that add missed diagnoses and remove unsupported ones. They’re using AI that explains its reasoning and builds an evidence trail for every coding decision.
The right question isn’t “how do we recapture lost revenue?” It’s: “how do we prove the clinical accuracy of every code we submit?” That’s the CMS HCC V28 reality in 2026. The model now rewards what should have been standard all along: accurate, encounter-linked, clinically evidenced coding that reflects the true complexity of the patients a plan serves. Plans that align to this standard are building a foundation that survives regulatory changes, audit cycles, and enforcement actions. Plans that don’t will keep chasing a model that no longer exists.
