The Centers for Medicare & Medicaid Services has confirmed it will shut down the Part D Premium Stabilization Demonstration at the end of this year, ending a two-year-old arrangement that used extra federal subsidy payments to keep standalone prescription drug plan premiums from spiking after the Inflation Reduction Act redesigned the Part D benefit. The demonstration only covered standalone plans, the kind bought by people who stayed on Original Medicare rather than a Medicare Advantage plan, and its exit means those premiums return to “traditional market conditions” for 2027, in the agency’s own words. For a household budgeting around a fixed drug plan premium, that change lands right as insurers finalize what they will actually charge for next year.
A Deputy Administrator’s Memo Ends a Two-Year Program
CMS announced the demonstration’s end inside a routine-looking technical bulletin, not a press release. In a memo dated July 28, 2026 and signed by John Brooks, Deputy Administrator and Director of the Center for Medicare, the agency states: “CMS is also announcing the conclusion of the Part D Premium Stabilization Demonstration (first implemented in CY 2025). For CY 2027, CMS analysis of the bids submitted indicates that Part D plan sponsors had sufficient experience under the redesigned Part D benefit to support their assumptions in developing prescription drug plan (PDP) bids. Therefore, CMS will discontinue the demonstration at the end of CY 2026 to return the program to operating under traditional market conditions in CY 2027.” A companion CMS fact sheet confirms the same conclusion and adds why the demonstration existed in the first place: to address “volatility and variation in standalone premiums following benefit changes mandated by the Inflation Reduction Act (IRA).”
Inside the kit: 51 state Medicare cost-help packs, the new Part D out-of-pocket cap, the prior-authorization appeal steps and a medication and cost tracker. Open The Medicare Cost & Coverage Protection Kit.
How the $15-and-$35 Mechanism Actually Worked
The demonstration’s mechanics are spelled out in a 2024 CMS actuarial guidance document issued when the program began. For a participating standalone plan, the demonstration cut $15 off the plan’s base beneficiary premium and capped how much a plan’s total premium could rise from one year to the next at $35. Neither cut cost the plan sponsor anything directly — CMS covered the full difference by increasing the direct subsidy payment it sends to participating sponsors, which is calculated as the plan’s risk-adjusted bid minus its basic premium. Lower the premium and the subsidy payment rises to match. The demonstration also narrowed the government’s risk-sharing thresholds for unanticipated drug costs, splitting losses between 2.5 percent and 5 percent above a plan’s bid projection instead of the standard 5-to-10-percent band, with CMS absorbing 90 percent of costs above the 5 percent mark rather than the usual 80 percent. Participation required a standalone sponsor to enroll every one of its plans, including employer-group plans, and a sponsor had to have participated the prior year to keep participating.
The Statutory Cap That Survives the Demonstration’s End
Ending the demonstration does not remove every premium protection Part D has. Separate from the demonstration, the Inflation Reduction Act caps the annual increase in the national base beneficiary premium at 6 percent through 2029. Under that cap, CMS set the CY2027 base beneficiary premium at $41.33 — the 2026 figure of $38.99 increased by 6 percent — instead of the $94.06 the underlying formula would have produced without the cap. That statutory ceiling is untouched by the demonstration’s end and keeps the national base figure from spiking. But CMS itself cautions that “actual premiums vary significantly from one Part D plan to another and seldom equal the base beneficiary premium,” which is exactly where the demonstration’s exit matters: the extra $15-and-$35 cushion applied at the individual standalone-plan level, on top of the national base premium, and that layer disappears for 2027.
The Deadlines Sponsors Already Faced
The wind-down carried its own calendar for insurers. Standalone Part D sponsors had from July 28 until 11:59 p.m. Pacific on August 6, 2026, to complete “rebate reallocation” — adjusting how much of their Medicare Advantage rebate dollars go toward buying down a Part D premium — using the finalized CY2027 benchmarks CMS released in the same memo. A second window, running from August 7 through August 11, 2026, let sponsors tell CMS whether they would volunteer to waive a small “de minimis” premium difference, set at $2 for 2027, to avoid low-income beneficiaries being reassigned to a different plan. Both deadlines have already passed, meaning the standalone plan bids submitted for 2027 were built without the demonstration’s cushion in place.
What Beneficiaries See Next
CMS says it will publish the finalized 2027 Medicare Advantage and Part D “landscape” — the plan-by-plan premium list beneficiaries actually see — in mid-to-late September 2026, ahead of the Medicare Open Enrollment period that runs annually from October 15 through December 7. Until that list is public, no individual standalone plan’s exact 2027 premium is confirmed; what is confirmed is that the extra subsidy layer built specifically to soften year-over-year increases on those plans will not be there to soften whatever number the landscape file shows.
Where a 2027 Premium Increase Shows Up Without a Warning Label
Ending a federal demonstration does not come with a personal letter explaining what a specific standalone drug plan’s 2027 premium will be instead of what the demonstration would have kept it at. That determination happens plan by plan when CMS finalizes the landscape file, and a household typically sees the new number only once it appears on enrollment paperwork, with no side-by-side showing what the premium would have been under the old cushion.
The Medicare Cost & Coverage Protection Kit is a 10-page kit covering the new Part D out-of-pocket cap and a medication and cost tracker, plus the prior-authorization appeal steps and 51 state Medicare cost-help packs.
Look up the new Part D out-of-pocket cap and start a medication cost tracker using The Medicare Cost & Coverage Protection Kit.
This article was produced with AI assistance and reviewed by a human editor. Figures are linked to their primary sources.
