If you received a letter this fall telling you that your Medicare Advantage plan is leaving your area at the end of the year, you are not alone — and you are not being singled out. Across the country, hundreds of thousands of Medicare beneficiaries are facing the same situation as major insurance carriers scale back or completely exit Medicare Advantage markets in dozens of counties. This is not a reflection of your health status or how much you've used your benefits. It is a business decision driven by rising healthcare costs, tighter federal reimbursement rates from the Centers for Medicare & Medicaid Services, and insurer profit pressures that have made certain markets financially unattractive to large carriers.
The scale of these exits is significant. According to CMS.gov data, the number of Medicare Advantage plans available nationally peaked in recent years, with beneficiaries in some counties having access to 40 or more plan options. But that abundance has begun to shrink in specific markets. CMS data from the 2025 plan year showed that while the national average number of MA plans available per county remained around 43, rural and lower-density counties saw meaningful reductions as carriers like Humana announced exits from hundreds of counties, affecting an estimated 560,000 beneficiaries for the 2025 plan year alone. Humana cited unsustainable medical cost ratios as the primary driver. Aetna similarly trimmed its footprint in select markets. When carriers exit, the ripple effect is immediate and personal for the people left holding a termination notice.
The first thing to understand when your plan exits is that you have rights — specific, time-limited rights that the federal government guarantees. When a Medicare Advantage plan terminates its contract with CMS or withdraws from your service area, you are automatically granted a Special Enrollment Period. This SEP gives you the ability to switch to another Medicare Advantage plan in your area, or to drop Medicare Advantage entirely and return to Original Medicare (Parts A and B). The SEP window is typically 63 days from the date your coverage ends, which in most cases means January 1 of the following year. That gives you until roughly March 4 to make a decision — but waiting until the last week is a mistake, because processing times and plan effective dates can create gaps.
Here is where many beneficiaries make a costly error: they assume that returning to Original Medicare is a safe fallback with no complications. It can be — but only if you understand the Medigap situation. Original Medicare alone covers roughly 80% of approved medical costs, leaving you responsible for the remaining 20% with no out-of-pocket maximum. To cap your exposure, most people pair Original Medicare with a Medigap supplemental policy (also called Medicare Supplement Insurance). The problem is that in most states, Medigap insurers can use medical underwriting outside of your initial enrollment window — meaning they can charge you more or deny you coverage based on pre-existing conditions. If you have diabetes, heart disease, a history of cancer, or other chronic conditions, you could find yourself unable to get a Medigap plan at a standard rate, or at all.
There are important exceptions to this underwriting risk. When your Medicare Advantage plan is discontinued and you return to Original Medicare, federal law grants you a guaranteed issue right for certain Medigap plans — specifically Plan A, Plan B, Plan C, Plan D, Plan F (if you were eligible for Medicare before January 1, 2020), Plan G, Plan K, or Plan L, depending on your state. This guaranteed issue right means the insurer cannot deny you or charge you more based on health. But this right is not unlimited — it applies only during your SEP window, and only if you act within the required timeframe. Missing that window could mean losing your guaranteed issue protection entirely.
If you live in one of the states with a birthday rule, you have an additional layer of protection worth knowing about. California, Idaho, Illinois, Kentucky, Louisiana, Maine, Maryland, Missouri, Nevada, New Jersey, New York, Oklahoma, and Oregon all have laws that give Medigap enrollees a 30-day window around their birthday each year to switch to an equal or lesser Medigap plan without medical underwriting. This is separate from the SEP triggered by a plan exit, but it can be a useful tool if you're trying to optimize your supplement coverage after returning to Original Medicare.
For beneficiaries who want to stay in Medicare Advantage rather than return to Original Medicare, the SEP triggered by a plan exit also allows you to enroll in any Medicare Advantage plan available in your county — with or without drug coverage. This is actually one of the broader SEPs available, because it is not limited to plans with the same structure as your old plan. If your old plan was an HMO, you can switch to a PPO. If your old plan had a $0 premium, you can evaluate whether a plan with a modest premium offers better network access or lower cost-sharing for the services you actually use. The Annual Enrollment Period (October 15 through December 7) is the most well-known window for MA plan changes, but your plan-exit SEP gives you comparable flexibility outside that window.
When comparing replacement Medicare Advantage plans, do not let a $0 premium be the only factor you evaluate. Look at the plan's maximum out-of-pocket limit — in 2025, CMS set the statutory limit at $9,350 for in-network costs and $14,000 for combined in- and out-of-network costs, but many plans set their own limits lower. A plan with a $25 monthly premium but a $3,500 out-of-pocket maximum may cost you far less over the course of a year than a $0-premium plan with a $7,000 cap, especially if you have regular specialist visits, physical therapy, or prescription drugs. Also check whether your current doctors and specialists are in the new plan's network — MA plans are largely network-based, and an out-of-network specialist visit can cost significantly more or may not be covered at all under an HMO structure.
Prescription drug coverage deserves its own careful review during any plan transition. If you are moving to a Medicare Advantage plan that includes Part D drug coverage (called an MA-PD plan), pull up the plan's formulary — the list of covered drugs — and check every medication you take against it. Formularies are organized into tiers, and the same drug can cost $10 per month on one plan and $85 per month on another depending on how it's tiered. Medicare's Plan Finder tool at Medicare.gov allows you to enter your specific medications and compare estimated annual drug costs across available plans in your zip code. This tool is free, does not require you to share personal contact information, and is updated annually with current plan data.
Data Snapshot: According to CMS.gov enrollment data, Medicare Advantage enrollment reached approximately 33.8 million beneficiaries as of early 2025, representing more than 54% of all Medicare-eligible individuals. CMS also reported that for the 2025 plan year, the average Medicare Advantage plan premium (weighted by enrollment) was approximately $17.00 per month — though a large share of enrollees remain in $0-premium plans. The number of MA plans available nationally for 2025 was 5,795, down slightly from the prior year's peak, with the reductions concentrated in specific rural and suburban counties where carrier exits occurred. Star ratings data from CMS showed that roughly 45% of MA enrollees were in plans rated 4 stars or higher — a metric worth checking when selecting a replacement plan, since higher-rated plans often have better care coordination and member services.
If you are not sure where to start, your State Health Insurance Assistance Program (SHIP) is a free, unbiased counseling resource funded by the federal government. SHIP counselors are trained specifically in Medicare and can walk you through your plan options, your SEP rights, and the Medigap guaranteed issue rules that apply in your state — at no cost and with no sales pressure. You can find your local SHIP contact through the Medicare.gov website or by calling 1-800-MEDICARE (1-800-633-4227). This is meaningfully different from calling an insurance broker, who may only present plans from carriers they represent.
One practical step that many beneficiaries overlook: if you receive a plan termination notice, keep it. That letter is documentation of your qualifying event for the SEP, and some insurers or Medigap companies may ask for proof that your prior plan was discontinued. Store it with your Medicare card and any other insurance documents. If you do not receive a formal termination notice but believe your plan is exiting your area, call your plan directly or check CMS's Medicare Plan Finder, which is updated to reflect plan availability for the upcoming year starting in October.
Finally, understand that a plan exit — while disruptive — can sometimes be an opportunity. Many beneficiaries stay in the same Medicare Advantage plan for years out of inertia, even as better options become available. Being forced to re-evaluate your coverage means you may discover a plan with a lower out-of-pocket maximum, better drug coverage, or added benefits like dental, vision, or hearing that your old plan did not include. The disruption is real, but the outcome does not have to be worse coverage. With the right information and enough time to compare your options carefully, most beneficiaries can find a replacement plan that meets or exceeds what they had before.