Three Major Medicare Advantage Insurers Are Narrowing Provider Networks for 2027, With Open Enrollment Days Away

With the Medicare Annual Enrollment Period starting October 15, three of the largest Medicare Advantage insurers are entering the season with narrower provider networks than a year ago. UnitedHealthcare, Aetna, and Humana have each scaled back their geographic presence or moved toward plan designs that include fewer in-network doctors and hospitals, according to a review of insurer disclosures published October 5, 2026.

UnitedHealthcare, the largest Medicare Advantage carrier, is reducing the share of members with access to both HMO and PPO options from roughly 70 percent in 2026 to about 66 percent in 2027. Aetna, owned by CVS Health, is expanding its HMO-style offerings while withdrawing from two states, moving from 43 states to 41, a shift expected to affect approximately 950,000 enrollees. Humana is reducing the share of US counties where it offers plans from about 85 percent to roughly 80 percent.

The moves reflect rising medical costs and utilization pressures that have strained Medicare Advantage margins in recent years. Carriers have responded partly by tightening the circle of in-network providers, which typically lowers plan costs but also restricts where members can seek care.

For beneficiaries, the practical risk is discovering that a doctor, hospital, or specialist covered this year is no longer in-network in 2027. The open enrollment window, running October 15 through December 7, is the annual opportunity to compare plans and make a change. Any switch takes effect January 1, 2027. Beneficiaries can review options at medicare.gov or by calling 1-800-MEDICARE.