A Medicare Advantage member whose plan ends on December 31 can apply for a Medigap policy as early as 60 days before coverage stops and as late as 63 days afterward. During that stretch, insurers must sell the policy. For a plan ending December 31, counting 63 days forward lands on March 4, 2027.
Who gets the Medigap guarantee when a plan ends
Medigap is private supplemental insurance that pays part of what Original Medicare leaves behind. Medicare.gov says a person has the right to buy a policy when their Medicare Advantage plan is leaving Medicare, will no longer cover their area, or when they move out of its service area. The same right applies if the plan misled them or broke the rules.
The page also says the application window opens 60 days before the plan’s coverage ends. It closes no more than 63 days after. Medigap coverage cannot start until the Medicare Advantage coverage has ended, and the page notes that selling Medigap to someone who still has a Medicare Advantage plan is illegal.
The guarantee is the point. The Minnesota Board on Aging’s release for this year’s exits says guaranteed issue lets enrollees buy Medigap without a health screening. Insurers have to sell during the window, whatever the member’s medical history looks like.
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Which exits are landing for 2027
Humana is the largest name. Healthcare Finance News reported on September 1 that Humana is exiting plans covering about 600,000 members for 2027. The insurer expects to move a bit more than 40% of them into its other plans. That leaves roughly 360,000 people, by that estimate, who need a new insurer or Original Medicare.
Humana chief financial officer Celeste Mellet told investors on the July 29 earnings call that the company intends to “remove or cut off the lower tail of profitability and returns.” Humana has not publicly named the affected counties or plans. Nonrenewal notices must be dated October 2 and were expected to arrive during October.
In Minnesota, the state Board on Aging estimates that 392,000 of the state’s 1.2 million Medicare beneficiaries will lose their current Medicare Advantage plan for 2027. Fifteen counties, from Aitkin to Yellow Medicine, will have no Medicare Advantage option at all.
Three Minnesota counties, Crow Wing, Lake of the Woods and Wadena, lose both Medicare Advantage and Medicare cost plans. Original Medicare is the only choice there. Minnesota Aging Pathways takes questions at 800-333-2433 on weekdays, and the release says the guarantee lets enrollees buy Medigap without a health screening.
Which Medigap plans insurers have to sell
The March 2026 CMS Medigap guide lists Plans A, B, C, D, F and G as the ones insurers must offer to someone leaving a Medicare Advantage plan, when the insurer sells them in the member’s state. Plans C and F are only open to people who became eligible for Medicare before January 1, 2020.
The medicare.gov web page words this more broadly, listing Plans A, B, C, D, F, G, K and L. Anyone shopping should ask each insurer which letters it sells in the state.
What the letters buy is the gap Original Medicare leaves. The guide describes one covered item as the Part B coinsurance, generally 20% of the Medicare-approved amount. That 20% is the cost that lands on a patient who leaves an Advantage plan and carries no Medigap.
What can sink the switch
The guarantee applies only to a member who goes back to Original Medicare. The guide says it does not cover someone who moves to another Medicare Advantage plan. A member who picks a replacement Advantage plan in open enrollment, which runs October 15 to December 7, gets no Medigap guarantee from that choice.
Paperwork is the second trap. The guide tells members to keep any letter, notice, email or claim denial that shows the coverage ended, along with the postmarked envelope. A Medigap insurer can ask for copies with the application, so the termination notice should not be thrown out with the other plan mail.
Timing is the third. Medigap cannot start before the Advantage coverage ends. Healthcare Finance News describes the window as opening when the member receives the termination notice and closing 63 days after the Advantage coverage ends. A member who waits to the last day spends weeks on Original Medicare alone.
Humana members have one more date. The special enrollment period for people dropped by an exiting plan runs from December 8 through the last day of February, according to that report. The Medigap window is a separate clock, and it is the shorter of the two.
A trial right works differently. A person who joined a Medicare Advantage plan when first eligible at 65, and leaves within the first year, can buy any Medigap policy sold in the state. Rights can last an extra 12 months under certain circumstances, according to the guide.
Members holding a nonrenewal letter now have two jobs in the same weeks: choose between another Advantage plan and Original Medicare, and keep the Medigap window from closing. Medicare.gov’s plan finder lists the plans and prices in a given ZIP code.
The choice is close to either-or. Medicare.gov says a person can buy Medigap or enroll in an Advantage plan, but cannot have both. A member who goes to Original Medicare needs a Medigap policy lined up before the old plan stops.
Got a plan ending letter and a March 4 clock?
A member who misses the 63 days after a plan ends can lose that protection, and a Medigap insurer can then ask health questions and decline. The plan letter is the proof that starts the clock, and many members file it with the junk mail.
The 2027 Medicare Open Enrollment Decision Kit includes a section on the Medigap buying rights that apply when a Medicare Advantage plan leaves, with a call script for the insurer. Part 4 covers the Medigap checkpoints and Part 6 holds phone scripts and a call log, so each call and date is written down.
Get the Medigap call script and plan-switch kit →
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This article was produced with AI assistance and edited for accuracy against the sources linked above.
