If you're one of the roughly 33 million Americans enrolled in a Medicare Advantage plan, you may have already received — or may soon receive — a letter that no beneficiary wants to open: your insurer is leaving your market. In recent years, major carriers including Humana, UnitedHealthcare, Aetna, and several regional Blue Cross Blue Shield affiliates have announced significant pullbacks from Medicare Advantage counties, citing rising medical costs, lower-than-expected reimbursements from the federal government, and tightening profit margins. The result is millions of beneficiaries scrambling to find new coverage, often with little time and even less guidance.
The scale of these exits is significant. For the 2025 plan year, Humana alone announced it was exiting Medicare Advantage markets in roughly 13 states, affecting an estimated 560,000 enrollees. UnitedHealthcare trimmed its footprint in dozens of counties. Smaller regional insurers have quietly dropped entire service areas with far less media attention. The Centers for Medicare & Medicaid Services (CMS) tracks these exits and requires insurers to notify affected members at least 90 days before a plan termination — but that still leaves many beneficiaries with a tight window to make one of the most consequential healthcare decisions of their lives.
When your Medicare Advantage plan exits your county or service area, federal rules automatically grant you a Special Enrollment Period (SEP). This SEP typically lasts 63 days from the date your plan coverage ends, and it allows you to enroll in any Medicare Advantage plan available in your area or return to Original Medicare (Parts A and B). Critically, this SEP is not the same as the Annual Enrollment Period (AEP), which runs October 15 through December 7 each year. Your SEP is triggered by the qualifying event of your plan's termination — meaning you don't have to wait for open enrollment season to act. Missing this 63-day window, however, can leave you in a coverage gap or force you onto a plan you didn't choose.
The financial stakes of switching plans are real and often underestimated. Medicare Advantage plans vary enormously in their cost structures. In 2025, the average Medicare Advantage plan premium was around $17 per month on top of the standard Part B premium of $185 per month, but many plans charge $0 in additional premium while others charge $100 or more. More importantly, out-of-pocket maximums — the most you'd pay in a year for covered services — can range from under $3,000 to the federal cap of $9,350 for in-network services in 2025. If you're switching from a plan with a low out-of-pocket maximum to one with a higher cap, a serious illness or hospitalization could cost you thousands more than you budgeted for. Before enrolling in any replacement plan, compare not just the monthly premium but the deductible, copays for specialist visits, and the annual out-of-pocket limit.
Your prescription drug coverage deserves equal scrutiny during any forced switch. Medicare Advantage plans that include Part D drug coverage (called MA-PD plans) each maintain their own formulary — the list of covered drugs and the tier at which they're covered. When you move to a new plan, your current medications may land on a higher cost-sharing tier, require prior authorization, or not be covered at all. Before you finalize a new plan selection, use the Medicare Plan Finder tool at Medicare.gov to enter your specific medications and see exactly what each plan will charge you for them. A plan with a $0 premium can easily cost you $200 or more per month in drug costs if your medications aren't well-covered — making it far more expensive than a plan with a modest premium but a favorable formulary.
Network disruption is the other major risk when plans exit markets. Medicare Advantage plans use networks of doctors, hospitals, and specialists, and when you switch plans, your current providers may not be in-network with your new insurer. This is not a minor inconvenience — it can mean losing access to your primary care physician, your cardiologist, your oncologist, or the hospital where you've received care for years. Before enrolling in a replacement plan, call your most important providers directly and ask whether they accept the specific plan you're considering. Don't rely solely on the insurer's online directory, which can be outdated. If continuity of care with specific providers is your top priority, you may find that returning to Original Medicare — which is accepted by virtually every doctor and hospital in the country that accepts Medicare at all — offers more flexibility than any Advantage plan.
Returning to Original Medicare is a legitimate and often overlooked option when your Advantage plan exits. Original Medicare covers approximately 80% of approved medical costs, leaving you responsible for the remaining 20% with no annual cap — which is why most people pair it with a Medigap supplemental policy. Here's where the situation gets complicated: Medigap plans typically require medical underwriting, meaning insurers can charge you more or deny coverage based on your health history. However, when you're involuntarily disenrolled from a Medicare Advantage plan due to a plan exit, federal law grants you guaranteed-issue rights for certain Medigap plans in most states. This means an insurer cannot deny you coverage or charge you more due to pre-existing conditions during this protected window. The specific Medigap plans available under guaranteed issue in this situation are Plan A, Plan B, Plan C, Plan D, Plan F (if you were eligible for Medicare before January 1, 2020), Plan G, Plan K, and Plan L — though availability varies by state.
State rules add another layer of complexity. If you live in California, Idaho, Illinois, Kentucky, Louisiana, Maine, Maryland, Missouri, Nevada, New Jersey, New York, Oklahoma, or Oregon, your state has a birthday rule or similar guaranteed-issue provision that gives you an annual window to switch Medigap plans without medical underwriting — independent of any plan exit situation. New York and Connecticut go further, requiring Medigap insurers to accept all applicants year-round regardless of health status. If you're in one of these states and your Medicare Advantage plan is exiting, you may have more Medigap options available to you than beneficiaries in other states. Contact your State Health Insurance Assistance Program (SHIP) — a free, unbiased counseling service available in every state — to understand exactly what your state-specific rights are before making any decisions.
The broader pattern of insurer exits reflects a structural tension in the Medicare Advantage program that is unlikely to resolve quickly. CMS sets the payment rates that insurers receive for each enrollee, and when those rates don't keep pace with actual medical costs — particularly as beneficiaries use more care post-pandemic — insurers respond by exiting unprofitable markets. Rural counties and lower-income urban areas tend to be hit hardest, as they often have fewer competing plans to begin with. In some counties, a plan exit can reduce the number of available Medicare Advantage options from a dozen to two or three, limiting your ability to find a comparable replacement. If you live in a rural area and your plan is exiting, checking whether Original Medicare plus a Medigap plan might actually serve you better than the remaining Advantage options in your area is worth serious consideration.
If you've received a plan termination notice, take these concrete steps immediately. First, read the notice carefully to identify your coverage end date and the start of your SEP. Second, log into Medicare.gov's Plan Finder and compare all available plans in your ZIP code, filtering by your medications and preferred providers. Third, call your doctors' offices to verify network participation with any plan you're seriously considering. Fourth, if you're considering returning to Original Medicare, contact your SHIP counselor (find yours at shiphelp.org) to understand your Medigap guaranteed-issue rights and get help comparing Medigap premiums in your area — which can vary by hundreds of dollars per year for identical coverage. Acting within your SEP window is not optional — it's the difference between having full control over your next plan and being auto-enrolled in a plan CMS selects for you.