The news: just four days before Medicare's Annual Enrollment Period opens, MarketWatch reports that at least 3.8 million Medicare Advantage enrollees will be forced to find new coverage for 2027, as major insurers exit markets and trim plan offerings to protect profit margins. According to data from healthcare policy firm KFF, the average Medicare beneficiary will have 35 Medicare Advantage plans to choose from in 2027, down from 39 in 2026 — and 181 counties will have no Medicare Advantage plan at all, up from just 67 this year, per a Modern Healthcare report.
The carriers pulling back include some of the biggest names in the business: UnitedHealth Group, Humana, and CVS Health's Aetna are among those exiting markets or adjusting coverage offerings, analysts told MarketWatch. Medicare's Annual Enrollment Period runs October 15 through December 7, 2026 — and this year, auto-renewing could leave you in a plan that no longer exists. Here is what is happening, why insurers are pulling back, and the steps to take now.
In this guide
The numbers: 3.8 million affected, 181 counties with zero plans
The scale of the 2027 pullback is significant. KFF's analysis shows the average beneficiary's choices dropping from 39 plans in 2026 to 35 in 2027 — what KFF called a modest decrease that still means some beneficiaries will find their current coverage is no longer an option for next year. In most cases, KFF noted, affected beneficiaries live in counties where robust alternatives remain available, alongside traditional Medicare.
The harder edge is the county-level picture: 181 counties will have zero Medicare Advantage plans in 2027, nearly triple the 67 this year, according to Modern Healthcare. In those counties, enrollees whose plans exited have no private-plan alternative — their practical choices are switching carriers (where none exist), dropping into traditional Medicare plus a Part D drug plan, or adding a Medigap policy if they can qualify. It is a sharp reminder that national averages can hide real local gaps.
Why insurers are pulling back
Insurers are being unusually open about the reason: margins. UnitedHealth Group, Humana, and Aetna have all signaled that protecting profitability — not chasing new subscribers — is the 2027 priority, analysts told MarketWatch.
Two forces are squeezing those margins. First, policymakers have moved to rein in payments to Medicare Advantage plans, which have consistently run above what the law intended, Matthew Fiedler of the Brookings Institution told MarketWatch. When plan benefits get trimmed back, the most obvious lever is cutting unprofitable markets and slimming plan lineups. Second, some insurers misjudged medical cost trends — utilization came in differently than expected, squeezing the difference between what plans collect and what they pay out.
There is also an eye-catching dollar figure in the background. The federal government pays Medicare Advantage plans an estimated 14% more per enrollee than it would spend if those same beneficiaries were in traditional Medicare, costing roughly $76 billion a year in additional federal spending, according to the Medicare Payment Advisory Commission's March 2026 report to Congress. That overpayment is exactly what the policy pushback is aimed at — and the current pullback is the industry's response.
Putting it in context: 2026 was worse
For perspective, the 2027 shakeup is actually milder than what seniors just lived through. A February 2026 analysis published in JAMA found that as much as 10% of the Medicare Advantage market was forced to find new plans for 2026 as insurers exited — with more than 20% of MA enrollees losing plans in 12 states, and 92% of Vermont's Medicare Advantage enrollees dumped from their plans. Brookings' Fiedler expects the MA market to remain "fairly robust" overall, with most beneficiaries still choosing among multiple plans that remain richer than traditional Medicare in some respects.
Still, yearly churn matters because benefits and costs change every year, even when your carrier stays put: the scope of extra benefits like vision and dental, out-of-pocket limits, referral requirements, prior-authorization rules, and provider networks can all shift. And this week the government released the other big 2027 signal — the 2027 Star Ratings, published October 8 — which reshuffle quality scores right as enrollment opens. See our companion guide to the 2027 Medicare Advantage Star Ratings for who moved up and down.
What it means for you before open enrollment
Medicare's Annual Enrollment Period runs October 15 through December 7, 2026, with changes taking effect January 1, 2027. If your plan was discontinued, your insurer must notify you — but you should not wait for that letter. Three things deserve your attention this year:
- Confirm your plan still exists for 2027. Start with your insurer's website or Medicare Plan Finder, and enter your county — availability is county-specific, and 181 counties just lost their last MA option.
- Re-shop even if your carrier stayed. Benefits, formularies, drug tiers, and networks can all change year to year. A plan that stays in your county but drops your doctors is functionally a different plan.
- Know your fallback. Traditional Medicare (Parts A and B) plus a standalone Part D drug plan, with or without a Medigap supplement, is always an option. If you are shopping for non-Medicare coverage for family members under 65, the ACA open enrollment starting November 1 has different rules — our guide to health insurance for the self-employed in the USA covers the basics.
What to do now: 5 steps for AEP
- Mark October 15 – December 7 on your calendar. Coverage changes you make during this window take effect January 1, 2027. Miss the window and you are generally locked in for the year.
- Read your Annual Notice of Change (ANOC). Your current plan mails this each fall. It lists exactly what is changing for 2027 — premiums, cost-sharing, drug tiers, network. A plan exit, a premium jump, or your doctors disappearing from the network are all re-shop signals.
- Compare plans on Medicare Plan Finder. Check your county's full 2027 lineup. Pair plan options with the 2027 Star Ratings — our Star Ratings guide shows which large carriers improved and which slipped.
- Verify your drugs and doctors before you commit. Confirm your medications are on the plan's formulary (and which tier) and that your physicians and hospital remain in network. A plan that exists in your county is only useful if it covers your care.
- Watch for scams. Enrollment season is prime time for Medicare fraud — never give your Medicare number to a cold caller or click links in unsolicited messages.
Frequently asked questions
How many Medicare beneficiaries have to change plans for 2027?
At least 3.8 million Medicare Advantage enrollees will be forced to find new coverage for 2027, according to a Modern Healthcare report cited by MarketWatch on October 10, 2026 — as major insurers including UnitedHealth Group, Humana, and Aetna exit markets or trim plan offerings.
When is Medicare open enrollment for 2027?
Medicare's Annual Enrollment Period runs October 15 through December 7, 2026. Plan changes and switches made during this window take effect January 1, 2027.
What happens if there is no Medicare Advantage plan in my county?
Traditional Medicare remains available everywhere. Your practical options are traditional Medicare (Parts A and B) plus a standalone Part D prescription drug plan, optionally with a Medigap policy. Note that Medigap underwriting rules vary by state — check whether guaranteed-issue protections apply to you.
Why are insurers leaving Medicare Advantage markets?
Insurers say they are prioritizing profit margins over growth. Policymakers have reined in federal payments to Medicare Advantage plans (which MedPAC estimates run about 14% above traditional Medicare costs, or roughly $76 billion a year), and some insurers misjudged medical utilization trends — both of which squeezed margins.