A Medicare Advantage, Part D, or Medicare Cost Plan insurer sometimes exits a market rather than renewing its contract with Medicare for the coming year, and the notice arrives by mail with little warning about what happens next. Members in that plan do not lose coverage overnight, but they do lose that plan once the contract ends, and the window to pick a replacement runs on a longer clock than the one most people associate with the fall sign-up season. The fallback, if nobody acts, is enrollment in Original Medicare, a program with a different cost structure than the plan that just left the market, which makes the length of that window and what it actually covers a household-budget question, not just a paperwork one.
The Window Runs From December 8 Through the End of February
Medicare’s rules treat a non-renewed contract as its own category of special enrollment period, separate from the annual sign-up season that ends in early December. A member whose Medicare Advantage plan, stand-alone drug plan, or Medicare Cost Plan is not being renewed for the next year can switch to a different plan any time between December 8 and the last day of February of the following year.
That timing matters because it opens right after the regular Open Enrollment Period, which runs October 15 through December 7 for anyone with Medicare, closes, and it keeps running for close to twelve more weeks into the new plan year. Anyone who misses the December 7 cutoff for an ordinary plan switch is not out of options if their plan is the one leaving the market; the special enrollment period rule for non-renewed contracts exists precisely because that member did not choose to be without a plan. Medicare’s own guidance is direct about the fallback: a member who does not join another Medicare Advantage plan before the old one ends is enrolled in Original Medicare automatically.
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Original Medicare Alone Has No Annual Cap on What a Member Pays
Defaulting into Original Medicare is not itself a penalty, but it changes what a member is exposed to for the rest of that plan year. According to Medicare’s own cost breakdown, there is no yearly limit on out-of-pocket spending under Original Medicare alone, unless the member also carries a Medigap policy or a Medicare Advantage plan with its own out-of-pocket limit. A Medicare Advantage plan, by contrast, is required to cap what a member pays for covered health services each calendar year, even though the exact dollar limit varies by plan.
The 2026 numbers behind that gap are specific. Part A carries a $1,736 deductible for each inpatient hospital benefit period, with no limit on how many benefit periods a member can have in a year, and Part B carries a $283 annual deductible plus a standard monthly premium of $202.90. A member who ends up on Original Medicare without any supplemental coverage in place is exposed to 20% coinsurance on most Part B services for as long as that gap lasts.
A Break In Drug Coverage Starts a 63-Day Penalty Clock
The financial risk sharpens for anyone whose non-renewed plan included drug coverage. Original Medicare by itself does not include a drug benefit, so a member who lets the switch window pass without lining up a new Medicare Advantage plan with drug coverage or a stand-alone Part D plan is running without prescription coverage. Medicare’s drug-cost guidance sets the threshold plainly: a late enrollment penalty applies once a member goes 63 or more days in a row without creditable prescription drug coverage after an initial enrollment period has passed.
That penalty is not a flat fee. It is calculated as 1% of the national base beneficiary premium, set at $38.99 for 2026, multiplied by the number of full months a member went without coverage, then added permanently to the monthly Part D premium for as long as that member carries drug coverage. A member who uses the non-renewal special enrollment period to pick a new drug plan before that 63-day count runs out avoids the calculation altogether; one who waits past it starts paying the penalty on top of whatever premium the new plan already charges.
The Medicare Advantage Open Enrollment Period Covers a Different Group
A second window opens in the same stretch of the calendar and is easy to confuse with the non-renewal special enrollment period. The Medicare Advantage Open Enrollment Period runs January 1 through March 31 each year, but it only applies to someone who is already settled into a Medicare Advantage plan and wants to make one additional change — switching to a different Medicare Advantage plan or dropping it to return to Original Medicare.
A member whose plan is not being renewed is working from a different rule with a different start date, a window that opened back on December 8. The two periods can overlap on the calendar for someone who joins a new Medicare Advantage plan under the non-renewal special enrollment period and then reconsiders that choice in January, February or March, but they are not the same permission, and confusing the two is one way a household loses track of which clock is actually running.
The $2,100 Threshold That Comes With Choosing a New Drug Plan
Picking a new drug plan inside the window also determines which cost stage a member starts the year in. Under Medicare’s 2026 structure, a drug plan’s deductible cannot exceed $615, and some plans charge none at all; after that deductible, a member typically pays 25% coinsurance on covered drugs until total out-of-pocket spending reaches $2,100 for the year, at which point Medicare’s catastrophic coverage stage takes over and the member owes nothing more for covered Part D drugs for the rest of the calendar year.
None of that structure applies to someone who has gone without any Part D or Medicare Advantage drug coverage at all — there is no deductible stage, no coinsurance stage and no catastrophic ceiling to reach, only the full retail cost of every prescription until a new plan is in place. That is the same math behind the 63-day penalty trigger, and it is the clearest argument for using the early weeks of the non-renewal window rather than waiting until the last days of February to act.
Comparing a New Plan’s Cost, Drugs and Doctors
A household that loses a plan this way still has to solve the actual comparison problem: which replacement plan covers the same drugs, keeps the same doctors, and costs less over a full year. The special enrollment period gives time to look, but Medicare’s plan finder does not print a side-by-side worksheet, and the separate calendars for open enrollment, the non-renewal window and the Medicare Advantage Open Enrollment Period rarely appear in one place. That gap is where the difference between a rushed pick and a good one usually opens up.
The 2027 Medicare Open Enrollment Decision Kit is a 42-page decision kit built around a cost calculator spreadsheet that compares plans on cost, drugs and doctors, along with a prescription-by-plan comparison, a provider call script and the Open Enrollment calendar.
Compare replacement plans side by side with The 2027 Medicare Open Enrollment Decision Kit.
AI-assisted research and drafting; reviewed by an editor.
