When a Medicare Advantage plan leaves Medicare altogether, federal rules give affected members a guaranteed-issue right to buy a Medigap policy, meaning insurers must sell certain Medigap plans regardless of any health condition on file and without charging a higher premium for one. CMS’s own guidance lists Plan A, B, C, D, F or G as the options covered by that right, with the request due no more than 63 days after the Medicare Advantage coverage actually ends. Humana’s decision to send exit notices to roughly 600,000 members by October 2 puts that guarantee to a real test this fall.
Medicare.gov’s guaranteed-issue rule and the plans it covers
A guaranteed-issue right is different from simply being allowed to apply for a Medigap policy. Outside a guaranteed-issue period, a private insurer can review an applicant’s health history through medical underwriting, charge more for a preexisting condition, or deny the application outright in most states that permit medical underwriting for Medigap. A Medicare Advantage plan leaving Medicare is one of several situations federal rule treats differently, requiring any insurer selling Medigap in that state to accept the application regardless of what shows up in the applicant’s health history.
Medicare.gov’s guidance on when a Medigap policy can be purchased lists “My Medicare Advantage Plan is leaving Medicare” as one of the qualifying situations, alongside moving out of a plan’s service area or a plan losing its Medicare contract. CMS’s own Choosing a Medigap Policy guide, updated March 2026, spells out that for this specific trigger the guarantee covers Medigap Plan A, B, C, D, F or G sold by an insurer in the member’s state, with Plan C and Plan F unavailable to anyone who became eligible for Medicare on or after January 1, 2020, leaving Plan D or Plan G as the closest equivalents for that group.
The same guide sets the application window on both sides of the transition: a member can apply as early as 60 days before Medicare Advantage coverage is scheduled to end and no later than 63 days after it actually ends, though the resulting Medigap policy cannot start until the Medicare Advantage coverage itself has ended. That two-sided window gives a member time to line up a Medigap policy before losing Medicare Advantage coverage entirely, rather than facing a gap with no supplemental coverage at all.
Inside the kit: The 2027 Medicare Open Enrollment Decision Kit pairs a cost calculator spreadsheet that compares plans on cost, drugs and doctors with a provider call script, useful once a Medicare Advantage exit forces a choice between a replacement Medicare Advantage plan and a guaranteed-issue Medigap policy paired with a separate Part D plan. Line up the Medigap and Medicare Advantage options in The 2027 Medicare Open Enrollment Decision Kit.
Humana’s October 2 exit notices put the guarantee to a real test this fall
Humana has said it will send non-renewal notices to roughly 600,000 Medicare Advantage members by October 2, 2026, one of several insurer exits reshaping the market for 2027. Members who receive those notices qualify for a special enrollment period running December 8, 2026 through February 28, 2027, to pick a new Medicare Advantage or Part D plan, a window separate from the 63-day guaranteed-issue clock for buying a Medigap policy instead, which starts from the date Medicare Advantage coverage actually ends rather than from the notice date.
Humana is not acting alone this year. Providence Health Plan is winding down operations affecting more than 64,000 members, Presbyterian Health Plan is discontinuing most of its Medicare Advantage offerings after reporting $59 million in 2025 losses, and UnitedHealthcare is exiting plans that together serve more than 600,000 members. Each of those departures triggers the same guaranteed-issue right for any affected member who chooses a Medigap policy over a replacement Medicare Advantage plan, regardless of which insurer is leaving or why.
What “without health questions” covers, and what it leaves out
The guarantee reaches medical underwriting, not price. An insurer offering a guaranteed-issue Medigap plan cannot charge a member more, deny the application, or impose a waiting period for a preexisting condition, but the plan still carries its own standard premium set by the insurer and the state, which can vary by hundreds of dollars a year between two insurers selling the identical Plan G benefits in the same area.
Medigap itself does not include prescription drug coverage, so a member who leaves Medicare Advantage for a Medigap plan also needs a separate stand-alone Part D plan to keep drug coverage, a second enrollment decision that runs on the same fall timeline as the Medicare Advantage exit but sits outside the guaranteed-issue right, which applies specifically to Medigap underwriting rather than to drug coverage. Original Medicare’s Part B, with its own deductible and 20 percent coinsurance on most services, remains the coverage a Medigap policy supplements, which is why the combination of Medigap plus a stand-alone Part D plan functions as a package rather than a single purchase.
Medicare.gov states the guaranteed-issue request must reach an insurer no more than 63 days after Medicare Advantage coverage ends, a deadline that runs independent of the special enrollment period insurers grant for picking a new Medicare Advantage or Part D plan instead. That leaves members affected by this fall’s exits with two overlapping but separately timed deadlines, one for underwriting protection and one for plan selection, to track through the same coverage change.
A guaranteed-issue window closes without a plan-by-plan comparison
Medicare.gov’s rule tells a member which Medigap plans an insurer must sell without health questions, not which of those plans, or which alternative Medicare Advantage plan, actually costs less for a given set of prescriptions and doctors. That comparison still has to happen inside the 63-day guaranteed-issue window and the special enrollment period Humana and other exiting insurers are granting this fall.
The 2027 Medicare Open Enrollment Decision Kit includes a cost calculator spreadsheet that compares plans on cost, drugs and doctors and the Open Enrollment calendar, tools built for weighing a guaranteed-issue Medigap policy against a replacement Medicare Advantage plan before either deadline closes.
Weigh the Medigap and Medicare Advantage paths in The 2027 Medicare Open Enrollment Decision Kit.
This article was researched and drafted with the assistance of AI and reviewed by The Money Overview editorial team.
