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calibrated on 2022/2023 data, we used the multiple linear regression methodology and average historical risk scores from 2019 through 2023. For the RxHCC model we are using solely for PACE organizations, we will continue to use the historical linear slope methodology and average risk scores from 2016-2020. • 2026 RxHCC model (2022/2023 calibration): o MA-PD plans: 1.194 o PDPs: 0.887 • 2026 RxHCC model (2018/2019 calibration) for PACE organizations only: 1.202 Sources of Diagnoses for Risk Scores calculated with the RxHCC Risk Adjustment Models: • For non-PACE organizations: CMS will continue the policy first adopted for CY 2022 to calculate all risk scores for payment to Part D sponsors using only risk adjustment- eligible diagnoses from encounter data and FFS claims. • For PACE organizations: CMS will calculate risk scores using 10 percent of the risk score calculated using encounter data and FFS claims only (under the 2026 RxHCC model (2022/2023 calibration)) and 90 percent of the risk score calculated using diagnoses from RAPS, encounter data, and FFS claims (under the 2026 RxHCC model (2018/2019 calibration). Annual Adjustments to Medicare Part D Benefit Parameters in CY 2026: As described in the CY 2026 Advance Notice, we will update the defined standard benefit deductible amount and the annual out-of-pocket threshold by multiplying the CY 2025 amounts by the CY 2026 Annual Percentage Increase and rounding as specified by the statute. Part D Calendar Year EGWP Prospective Reinsurance Amount: As finalized in the Final CY 2026 Part D Redesign Program Instructions published concurrently with this CY 2026 Rate Announcement1, we will continue to use the updated methodology finalized in the Final CY 2025 Part D Redesign Program Instructions to calculate the prospective reinsurance payments to all Part D Calendar Year EGWPs. Part D Risk Sharing and Additional Premium Stabilization: As discussed in the CY 2026 Advance Notice, we will apply no changes to the current threshold risk percentages for MA-PDs for CY 2026. Given the significant changes in the Part D benefit in 2025, CMS is conducting a voluntary demonstration that provides additional premium stabilization and narrowed risk corridors for participating PDPs in CY 2025. Since changes to the Part D benefit will be relatively modest in

1 Refer to CMS’ Draft CY 2026 Part D Redesign Program Instructions and Final CY 2026 Part D Redesign Program Instructions.