PY2027 Advance Notice Deep Dive: Impact of Unlinked Supplemental Submissions

On January 26, 2026, CMS released the 2027 Medicare Advantage and Part D Advance Notice. There are hundreds of AI-generated summaries out on LinkedIn, so we chose to perform a deep dive on one of the more impactful proposed rules within risk adjustment, the elimination of unlinked supplemental records and their impact on RAF.

Background

CMS has allowed MAOs to submit supplemental records to support the documentation of accurate member clinical acuity as unlinked supplemental records via EDS, meaning they do not have to be joined (or “linked”) back to a claim. In contrast, HHS has required issuers to link all supplemental records back to a submitted and accepted claim since the inception of the program in 2014.

Unlinked supplemental records are commonplace in MA. They derive primarily from retrospective chart reviews where the combination of a member, provider, and date of service (“DOS”) within a medical record substantiate that the member was evaluated, assessed, and treated for a condition, though the health plan cannot find a commensurate match within their claims data. The secondary cause of unlinked submissions is from ancillary clinical vendors who choose not to submit traditional claims (e.g., in-home assessments, virtual care). CMS’ proposed rule will alter how those vendors must submit data to MAOs and the methodologies MAOs apply to link supplemental records.

Prohibiting unlinked chart reviews will eliminate another common practice by MAOs, which is to chase medical records for New to Plan members in the prior year (i.e., those members that join with a RAF score from either Fee-for-Service Medicare or another Medicare Advantage plan).

Complexities of Linking

Official guidance on how to link supplemental encounters to claims has not been published for either the MA or ACA market, providing ambiguity and inconsistency in how plans link. When we surveyed our ACA Pareto Community clients in 2024, we uncovered varying methodologies, typically applied hierarchically with the most restrictive first, then loosening requirements.

Most common, and least restrictive response, was Member ID + TIN + Exact DOS up to +/- 5-7 days.

To further complicate things, ACA RADV guidelines for Independent Validation Auditors (“IVAs”) states when the following two criteria are met, “the IVA Entity may abstract all diagnoses within the applicable benefit year according to ICD-10 and ICD-10-PDS guidelines, including other dates of service within the benefit year being audited and associated diagnosis codes found on the medical record.”

1. All authenticated medical records from inpatient hospital, outpatient, and professional sources must match the demographic data for the sampled enrollee on the UID mapping documentation.
2. The medical record must be linked to EDGE server accepted RA eligible claim from the RADV/MCE Report where the claim’s statement covers from date or statement covers through date aligns to at least one of the dates of service found on the medical record.

The ACA RADV guidelines state that as long as one date matches, the rest of the medical record is allowable for inclusion. This contradicts how most ACA plans apply DOS as a required linking parameter.

Now do you understand the ambiguity facing MAOs????

Analysis

Pareto analyzed our MA Community of clients to understand the prevalence of unlinked submissions. We analyzed YTD PY2025 CMS data (2024 DOS) throughout January 2026 and scored on the v28 model version. With the PY2025 EDS submission deadline being February 2, 2026, the following does not include all final adjustments made in the last week of submissions but still provides a full year representation.

Note: Pareto had three MA clients submit 100% of their supplemental claims as linked, representing less than 8% of the total Pareto Community membership. They have been removed to provide more insight into the range of outcomes across MAOs, as most MAOs have a mix of linked and unlinked supplemental records.

• 2–5% of all encounters submitted were supplemental, with the lowest being 0.7%, highest exceeding 20%.
• On average, 38% of supplemental encounters were unlinked, with a wide range from 5% to 90%+.
• Assuming all unlinked were denied, the impact to RAF on average was:
  • Members impacted: 1.0%
  • Diagnostic HCCs Scored: 2.3%
  • RAF Impact: (1.3%)
  • Premium Impact: (1.4%)

Overall, Pareto’s calculation is in line with the (1.53%) RAF impact estimated by CMS, though the RAF impact across Pareto Community plans ranged from 0.1% to over 3.5%. This presents a wide variance across MAOs and has significant financial implications in a market where every basis point matters.

Considerations & Next Steps

Assuming the Proposed Rule holds and the elimination of unlinked supplemental records goes into effect, Pareto recommends MAOs take the following action:

• Quantify your own impact. The PY2025 EDS submission deadline just passed, so perform a post-deadline analysis of your supplemental submissions and quantify the RAF impact. It is important to note that this is a go-forward proposed rule, so there is no clawback on prior performance years and MAOs have time to remediate their practices.
• Understand the various sources and define a plan. As defined above, there may be multiple sources of unlinked supplemental records (e.g., IHAs, virtual care, chart reviews). For non-chart reviews, proactively engage those vendors/providers and begin defining an implementation plan for them to submit claims. Whether they are $0 claims or some other amount, test to ensure they are not rejected and do not generate any unintended charges to members.
• Define and test your linking logic. Define and test multiple linking methodologies and understand the implications and sensitivity of each parameter.
• Engage your regulators and auditors. Leverage your relationships with CMS and your RADV partners for guidance.

*Disclaimer: This article is not intended to provide guidance or recommendations on how to submit supplemental records for the MA and ACA market, rather to provide insight into proposed regulations and our observations in the market.

Need help quantifying your organization's exposure to the proposed unlinked supplemental records rule? Pareto Intelligence offers comprehensive risk adjustment analytics and regulatory compliance support for Medicare Advantage Organizations. Contact us at contact@paretointel.com to learn how we can help you navigate regulatory changes and protect your RAF performance.