Medicare Advantage enrollment 2025: Winners and losers

The more things changed for Medicare Advantage in 2025, the more they stayed the same.

The 2025 plan year marked a turning point for Medicare Advantage, as insurers spooked by unfavorable new regulations, low federal reimbursement, an unexpected rise in medical expenses, a marketing crackdown and pushback from providers, stopped selling policies. Previously, insurers viewed the annual sign-up period as an opportunity to capture as many new members as possible.

Yet despite the upheaval, the program’s three largest insurers – UnitedHealthcare, Humana and Aetna – maintained their grip on the market although their combined share of policyholders slipped, to 58%, from 59%, according to a Modern Healthcare analysis of enrollment data released Tuesday by the Centers for Medicare and Medicaid Services.

Related: 2025 Medicare Advantage market takes shape amid turmoil

The UnitedHealth Group subsidiary was the big winner, gaining almost 400,000 policyholders, while Humana lost the most policyholders, about 413,000.

Blue Cross Blue Shield licensees Elevance Health, Blue Cross Blue Shield of Michigan and Excellus BlueCross BlueShield also had big gains. Their growth could pose a double-edged sword. A flood of new members could disrupt insurers' financial assumptions. At the same time, new members offer regional insurers the opportunity to retrench in their core areas.

Cigna, which is about to exit the Medicare Advantage marketplace, posted gains as well. The company plans to close the $3.3 billion sale of its Medicare Advantage plan to Health Care Service Corp. before March 31.HCSC manages Blue Cross plans in five states — Illinois, Montana, New Mexico, Oklahoma and Texas.

Annual enrollment grew 4% to 34.4 million policyholders. That represents the slowest year-over-year growth rate since at least 2007, according to KFF, a health policy research organization.

The enrollment numbers represent the first clear indication for investors, insurers and marketers about how companies performed. President Joe Biden’s administration released sign-up data last month but retracted its report after finding inaccuracies. 

Companies depend on the information to help set their competitive strategy for 2026. Medicare Advantage insurers' bids are due to CMS in early June and companies have already started crafting their plans. Humana and Aetna, for instance, are engaged in multiyear plans to recover profitability. The two insurers made the largest reductions to the business this year after posting negative margins.

Other companies showing enrollment declines included Centene and Florida Blue. Unlike Centene, Florida Blue and Humana, Aetna did not sue CMS to boost their Medicare Advantage Star Ratings for 2025. Insurers with high ratings receive big bonuses.

Insurtech Devoted Health also posted a large drop in enrollees, losing nearly 15% of its 243,000 members. In August, the privately held company was valued at more than $13 billion after raising another $112 million. The company in previous years was one of the fastest-growing Medicare Advantage insurers.