A cancellation notice from a Medicare Advantage insurer rarely explains what it hands the recipient along with the bad news. Buried in that letter is a narrow, one-time right to buy a Medicare Supplement, known as Medigap, without answering a single health question — a right that disappears if the paperwork misses its deadline. The rule sits inside federal Medicare law and runs every year, not just during this fall’s plan-letter season. It is easy to miss precisely because nothing about it arrives stamped “urgent,” even though the underwriting consequences of missing it are permanent.
The 63-Day Guaranteed-Issue Window After a Medicare Advantage Plan Ends
Medicare’s guaranteed-issue guidance sets a firm filing band around the date Medicare Advantage coverage stops: the Medigap application can go in as early as 60 days before that end date, and no later than 63 days after it. Miss the back edge of that window and the guaranteed-issue right is gone, regardless of how healthy the applicant otherwise is. Medicare’s own enrollment tool repeats the same 63-day figure across every Medicare Advantage exit scenario it walks through, from a plan leaving the program entirely to a member switching back to Original Medicare.
That timing rule decides who has to answer health questions and who does not. Inside the window, the insurance company selling the Medigap policy has to sell it, cannot charge more because of a pre-existing condition, and cannot delay the start of coverage beyond what is medically necessary. Outside it, the same insurer is generally free to run medical underwriting and reject the application, a distinction the Centers for Medicare & Medicaid Services lays out on its Get ready to buy page. That page also describes the separate, one-time six-month Medigap Open Enrollment Period that opens for everyone the first month they have Part B and are 65 or older — a different clock than the 63-day guaranteed-issue window, and one that never returns once it closes.
Inside the decision kit: A cost calculator spreadsheet comparing plans on cost, drugs and doctors, a prescription-by-plan comparison, a provider call script and the Open Enrollment calendar. Open The 2027 Medicare Open Enrollment Decision Kit.
What Losing a Medicare Advantage Plan Actually Triggers
Medicare’s enrollment tool lists a specific set of exits that open the guaranteed-issue window: the Medicare Advantage plan leaving Medicare altogether, the plan pulling out of the county where the member lives, the plan dropping the member’s home address from its service area, or the plan failing to follow its marketing and enrollment rules or misleading the member into joining. Each counts as coverage ending through no choice of the member’s own, which is the condition the guaranteed-issue right is built around.
A member who voluntarily drops a Medicare Advantage plan during the yearly Open Enrollment Period simply to try a different plan does not trigger this right. Medigap coverage in that case depends on medical underwriting, unless a state offers broader protection than federal law requires.
Why “Guaranteed Issue” Means an Insurer Cannot Say No
Guaranteed issue is a specific legal status, not marketing language. Medicare’s guidance describes identical protections for the one-time Medigap Open Enrollment Period that opens when someone first turns 65 and signs up for Part B: no medical underwriting, no higher premium for past health problems, no waiting period tied to a pre-existing condition. A member exercising a guaranteed-issue right after losing Medicare Advantage coverage gets the same protections. An insurer licensed to sell Medigap in that state has to issue one of the standardized guaranteed-issue policies regardless of the applicant’s diagnosis history.
Medicare’s enrollment tool names the specific policies covered by that guarantee for someone losing a Medicare Advantage plan: Plan A, B, C, D, F, G, K or L, whichever a given company sells in the applicant’s state. The insurer cannot substitute a thinner policy or push the applicant toward a plan it would rather sell; the choice among whichever of those letters it offers belongs to the applicant, not the company.
The 12-Month Trial Right for First-Time Medicare Advantage Enrollees
A related protection covers people trying Medicare Advantage for the first time. Medicare’s enrollment tool confirms that someone who joined a Medicare Advantage plan when first eligible for Medicare, or within the past 12 months, keeps the right to switch back to Original Medicare and buy the specific Medigap policy held before joining, or any Medigap policy sold in the state if that earlier policy is no longer available. The same 60-day-before, 63-day-after filing band governs that trial-right switch.
Proving the Clock Started
Medicare’s guidance is specific about documentation: a Medigap insurer can require proof of exactly when the earlier coverage ended before honoring a guaranteed-issue application. That means keeping the cancellation letter, the plan’s non-renewal notice, or a claim denial that shows the date, since a missing paper trail can stall an application that otherwise qualifies. A member unsure whether a particular letter is enough can call the local State Health Insurance Assistance Program, a counseling service funded by the Administration for Community Living at the U.S. Department of Health and Human Services, for a free review of the paperwork. The program’s national technical assistance center, run out of the Northeast Iowa Area Agency on Aging, coordinates the network of local counselors who field exactly these documentation questions at no charge.
State Law Can Add to the Federal Floor
The 63-day figure is a federal floor, not a ceiling. Medicare’s own guaranteed-issue guidance directs applicants to check with their state insurance department, noting that state law can grant additional rights beyond what federal law requires — several states, for instance, extend guaranteed-issue protections to Medicare beneficiaries under 65, a group federal law does not automatically cover. Nothing at the state level can shorten the federal 63-day window; state regulators can only add protections on top of it.
Sixty-Three Days and a Signature
The guaranteed-issue clock above only starts once a Medicare Advantage plan actually ends, but the decision about whether to leave a plan happens earlier, during the Medicare Open Enrollment Period each fall. That decision turns on the Annual Notice of Change a plan mails out, which resets premiums, drug tiers and provider networks for the year ahead and is easy to skim past. Getting that comparison wrong is often what puts a household into the guaranteed-issue scramble described above in the first place.
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, alongside a prescription-by-plan comparison, a provider call script and an Open Enrollment calendar.
See the cost calculator, prescription comparison and provider call script in The 2027 Medicare Open Enrollment Decision Kit.
AI-assisted research and drafting; reviewed by an editor.
