A look at Part D enrollment trends for 2026

Just over 56 million people are enrolled in Medicare Part D, with the share of those securing coverage through Medicare Advantage Prescription Drug (MAPD) plans growing alongside the overall program.

As of 2026, 24.9 million people were enrolled in standalone Part D plans, according to a new analysis from KFF, while 31.4 million were in MAPD plans. By comparison, overall enrollment in 2006 was just 21.8 million, with 15.8 million of those individuals with just Part D coverage.

The data for 2026 do reflect slight growth year over year in the number of people with standalone Part D, as 23.2 million were enrolled in just the prescription drug coverage for 2025.

The report found that enrollment in non-group MAPD plans has steadily risen over the past several years, while sign-ups for non-group standalone prescription coverage has plateaued.

Meanwhile, it’s the opposite story in employer group Medicare, according to the report. Enrollment in employer group MAPD plans fell from 3.9 million to 2.7 million between 2025 and 2026, while sign-ups for group Part D plans rose from 5.1 million to 6.3 million.

This marks the first time enrollment in employer group MAPD coverage has declined, the KFF researchers said.

The researchers note that this shift may be in response to the Part D premium stabilization program, instituted last year, which is applicable only in standalone prescription plans and not MA plans. In employer Part D plans, the program would afford $10 per member per month in additional subsidies.

“This strategy would enable groups to take advantage of the Part D premium stabilization demonstration and receive additional premium subsidies provided by the federal government, which are available only to PDPs that choose to participate, not MA-PDs,” the researchers wrote.

The study also dove into which individual payers saw the largest increases in their Part D enrollment, with Humana and Centene leading the way. Enrollment in Humana’s prescription drug plans grew by 61% from 2.3 million to 3.7 million.

Centene saw an 11% increase, with its PDP enrollment increasing from 7.8 million to 8.7 million.

UnitedHealthcare saw more modest growth in Part D enrollment for 2026, while Aetna and Health Care Service Corporation saw enrollment decline. Humana and Centene had lower enrollment weight premiums in Part D for 2026 compared to the others.