You May Get Two Envelopes From Your Insurer This Fall. One Says Your Plan Changed. One Says It’s Gone. Only the Second One Comes With a Medigap Right

Two envelopes land in the mailbox this fall, both bearing the same insurer’s logo. One announces that next year’s copays, drug tiers, or out-of-pocket maximum are moving. The other says the plan itself will not exist after December 31. They look alike but differ in one crucial way: only the second one opens a federal door to buy Medigap without a health questionnaire, and that door closes fast.

If neither envelope has arrived, or if the second one never comes, the stakes here are lower. Millions of Medicare Advantage members will get only the first letter and can shop calmly during Annual Enrollment. The alarm is for the member holding the second envelope, or worried they might be about to.

The scale of this year’s terminations is unusually large. CMS data analyzed by KFF found that 4.3 million Medicare beneficiaries, including 3.1 million Medicare Advantage drug plan enrollees and 1.2 million stand-alone Part D enrollees, will have their plans terminated at the end of 2026. At least 11 health insurance companies that sold individual Medicare Advantage plans in 2026 are abandoning the program entirely for 2027, compared with seven carriers that exited in 2026. After these exits, 181 counties will have no Medicare Advantage plan available at all, up from 67 this year. For members in those counties who receive a termination notice, this is not comparison shopping. It is a forced transition.

One Letter Changes the Plan

The Annual Notice of Change, or ANOC, is the routine one. Plans continuing into 2027 had to deliver the ANOC by September 30. It lays current-year and coming-year terms side by side: premium, primary and specialist copays, hospital cost-sharing, drug formulary tiers, the in-network out-of-pocket maximum, and any supplemental benefits.

A steep cut, a lost dental allowance, or a specialist copay that doubled does not create any special federal right. The member can switch plans during Annual Enrollment, October 15 through December 7, but returning to Original Medicare and buying a Medigap policy at that point generally means medical underwriting. An insurer can review the applicant’s health history and choose to reject the application, charge a higher Medigap premium, or impose a waiting period before covering a preexisting condition. If the member has developed diabetes, a cardiac issue, or a cancer history since first enrolling in Advantage, that is the trap.

Second Letter Ends the Plan

A nonrenewal or termination notice says the plan will no longer be offered where the member lives. Under 42 CFR §422.506(a)(2), insurers must mail it at least 90 days before coverage ends, which puts it in the mailbox around early October for a December 31 termination. Look for direct language: “will not be offered,” “will not renew,” “coverage will end.”

The notices are already circulating. UnitedHealthcare mailed non-renewal notices dated October 2, 2026, to affected members. Humana announced targeted plan exits expected to affect roughly 600,000 of its members. An additional 1.4 million Medicare Advantage enrollees are in plans that will consolidate into another plan offered by the same insurer, which produces an ANOC rather than a termination notice. The distinction matters enormously for the Medigap rights that follow.

This notice forces a decision. It is not an invitation to comparison shop. The member must choose replacement coverage or default back to Original Medicare on January 1 with no drug plan and no supplement in place.

Hidden in Plain Sight

Plan termination triggers a federal Medigap guaranteed-issue right for a member who returns to Original Medicare. During the protected window, participating Medigap insurers cannot deny the application, charge more because of health, or impose a preexisting-condition exclusion. The governing statute is 42 U.S.C. §1395ss(s)(3)(B)(ii).

Anyone first eligible for Medicare on or after January 1, 2020, can generally choose Plans A, B, D, G, K, or L. Beneficiaries who became eligible before that date may still reach Plans C or F. The protection runs from the arrival of the termination notice until 63 days after coverage ends, reaching into early March 2027 for a December 31, 2026 termination. A handful of states layer on broader continuous or annual guaranteed-issue rights; the federal window is the floor.

Why does that matter in dollars? Original Medicare carries no out-of-pocket maximum on its own. The 2026 Part A inpatient deductible is $1,736 per benefit period, and skilled nursing coinsurance runs $217 per day for days 21 through 100 (up from $209.50 in 2025). Plan G absorbs almost all of that exposure after the $283 Part B deductible. Locking in Plan G without underwriting, in a year when a health event has already happened, can be worth tens of thousands over a decade (we cataloged the other premium surcharges and coverage gaps that ambush retirees in a free Medicare guide here).

Worst of Both Worlds

The member can pick another Medicare Advantage plan during Annual Enrollment. A nonrenewal also opens an additional Special Enrollment Period running December 8 through the last day of February. Waiting until January or February pushes the new plan’s start date into the following month, creating a gap in drug coverage. Doing nothing generally lands the member on Original Medicare on January 1 with no Part D and no Medigap, which is the worst of both structures.

What to Do With Both Envelopes

• Keep the termination notice. It is the proof of the guaranteed-issue event, and Medigap insurers will ask for it.
• Decide the direction, another Advantage plan or Original Medicare with a Part D plan and a Medigap policy, before the December 31 cliff. If choosing Medigap, apply before Advantage coverage ends rather than burning through the 63-day cushion.
• Confirm which Medigap letters and deadlines apply locally with the state insurance department or the free State Health Insurance Assistance Program (SHIP).

The ANOC tells the member what staying will cost. The non-renewal notice says staying is no longer possible, and it opens a Medigap door that will not stay open past early March.

Editor’s note: This article was updated to include CMS data showing 4.3 million Medicare beneficiaries will have plans terminated at the end of 2026, the departure of at least 11 insurers from Medicare Advantage for 2027 (up from 7 the prior year), the specific number of counties that will have no Medicare Advantage plan available (181), and the confirmation that the 2026 skilled nursing facility coinsurance of $217 per day for days 21 through 100 rose from $209.50 in 2025.

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