Medicare Advantage plans sometimes stop serving a county or exit the Medicare program entirely, and every member enrolled in one has to actively pick new coverage during the fall Open Enrollment period. Members who take no action are not left uninsured. Instead, Medicare’s default puts them into Original Medicare, Part A and Part B, without the drug coverage, extra benefits or out-of-pocket cap that many Medicare Advantage plans bundle in. That default carries a specific dollar exposure: Original Medicare has no yearly limit on what a member pays out of pocket, and going without a separate Part D drug plan for 63 days or more can trigger a monthly penalty that lasts for as long as that person carries Medicare drug coverage.
The Default When a Plan Leaves Is Original Medicare, Not a Gap
A Medicare Advantage Plan that exits a county or leaves the Medicare program entirely does not simply cancel a member’s coverage on the spot. Every affected member gets the fall Open Enrollment period to pick something new, and a member who doesn’t switch to another Medicare Advantage Plan during that window does not go without insurance at all. That member is instead moved into Original Medicare, the baseline hospital and medical coverage that predates Medicare Advantage, and nothing else comes attached to it automatically.
Medicare’s own guidance on buying a Medicare Supplement Insurance, or Medigap, policy spells out exactly that mechanism for anyone whose plan exits the market: a member who doesn’t switch plans during Open Enrollment is automatically enrolled in Original Medicare. No prescription drug plan, no Medigap policy, and no cap on annual cost-sharing arrives with that default. A member who does nothing during a plan’s exit isn’t choosing Original Medicare so much as inheriting it, coverage gaps included, unless a separate application for Part D or Medigap follows on its own before that Medicare card becomes the only coverage in the wallet.
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No Yearly Cap on What Original Medicare Can Cost
The exposure that matters most is stated plainly on Medicare’s cost page: there’s no yearly limit on out-of-pocket spending under Original Medicare unless a member also carries supplemental coverage, such as a Medigap policy, or joins a Medicare Advantage Plan. A member who lands in Original Medicare by default and adds neither protection faces Part A and Part B cost-sharing with no ceiling for the calendar year. A single hospitalization, a run of specialist visits, or a chronic condition requiring ongoing outpatient care can keep generating bills with nothing to stop the total.
The 2026 Numbers Behind the Exposure
For 2026, that same cost page sets the Part A inpatient hospital deductible at $1,736 per benefit period, with coinsurance of $434 a day for days 61 through 90 of a hospital stay and $868 a day for the 60 lifetime reserve days that follow. A member who exhausts those reserve days pays the full cost of any further inpatient stay, and because there’s no limit on how many benefit periods a person can have in a year, that deductible can apply more than once. Part B adds its own $202.90 monthly premium, a $283 annual deductible, and 20% coinsurance on most Medicare-approved services once the deductible is met. None of those coinsurance figures come with a yearly stopping point of their own. Together, they describe exactly what a member who does nothing when a Medicare Advantage plan leaves is opting into, without ever making an active decision to accept it.
A Permanent Penalty for Going Without Part D
Original Medicare enrollment carries no prescription drug coverage attached, and Medicare’s penalty guidance spells out what happens to a member who goes 63 days or more without a Part D plan or other creditable drug coverage: a penalty equal to 1% of the national base beneficiary premium, multiplied by the number of full months without coverage, gets added permanently to that member’s monthly Part D premium for as long as that person carries Medicare drug coverage, even after switching plans. The national base beneficiary premium is $38.99 in 2026, so a member who went 14 months without coverage, Medicare’s own example figure, would owe a 14% penalty, or $5.50 a month on top of whatever premium a plan charges. Members who switch to Original Medicare separately get at most 63 days after Medicare Advantage coverage ends to buy a Medigap policy with guaranteed issue rights, but that clock runs independently of the Part D deadline and closes on its own schedule.
The October 15-December 7 Window to Avoid the Default
The fix is time-boxed. Open Enrollment runs from October 15 through December 7 every year, and any change made during that window takes effect January 1, provided the new plan receives the enrollment request by December 7. A member whose Medicare Advantage Plan is exiting the market can use that same window to actively pick a different Medicare Advantage Plan, or to select Original Medicare on purpose and pair it with a Part D plan and, where eligible, a Medigap policy, rather than let the default enrollment take effect on its own on January 1. Medicare’s guidance is direct about the stakes for anyone switching to Original Medicare, noting a member “may need to join a separate drug plan and may want to add Medicare Supplement Insurance (Medigap)” because there are limits on when that protection can be added later.
This article was produced with the assistance of AI and reviewed by The Financial Wire editorial team.
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David M. Keller is a finance writer based in Columbus, Ohio, covering personal finance and consumer-focused economic topics. He earned his degree in journalism from Ohio University and began his career reporting on local business and economic trends for a regional media outlet. Since then, he has contributed to a variety of online publications, focusing on clear, practical coverage of topics such as cost of living, debt, and everyday financial decision-making.
