A KFF analysis projects that average monthly premiums for stand-alone Medicare prescription drug plans will jump 50%, from $34 in 2026 to $51 in 2027. Enrollees can shop for a different plan during open enrollment, which ends Dec. 7, and may avoid much of the increase by switching.

The impact could be widespread: KFF estimates that 10.4 million people—76% of stand-alone plan enrollees without low-income subsidies—will pay higher premiums if they stay in their current plans. That includes 4.1 million people now in zero-premium plans, since none will be available among stand-alone plans in 2027.

KFF’s forecast is far steeper than the Centers for Medicare & Medicaid Services’ estimate, which puts the national average premium increase at just $35 to $36 in 2027. KFF said CMS did not explain its methods and may have assumed beneficiaries would move to cheaper plans; CMS did not immediately comment on the analysis.

KFF pointed to the early end of a federal subsidy pilot as one possible factor behind higher stand-alone premiums. The Centers for Medicare & Medicaid Services ended the three-year program after two years, and CMS Administrator Mehmet Oz called it an insurance-industry bailout.

Some beneficiaries are already looking for alternatives. Robert Travis Scott of Abingdon, Virginia, switched after learning his AARP-UnitedHealthcare premium would rise from $39.60 to $121.90 a month; he found a Humana plan with similar benefits for $19.30 and estimated he would save about $1,000 in 2027.

Premiums are only part of the expected cost increases: average annual drug deductibles are projected to rise from $540 to $643 for stand-alone plans and from $360 to $489 for Medicare Advantage drug coverage. Most enrollees will also face coinsurance, meaning they pay a percentage of a drug’s cost rather than a fixed copayment.

By comparison, people with drug coverage through Medicare Advantage are projected to pay an average of $9 a month for drugs in 2027, an increase of less than $2. More than half of Medicare beneficiaries use Medicare Advantage, while nearly 25 million have stand-alone drug plans and about 31 million get coverage through Medicare Advantage.

The projected increases come as President Donald Trump says his administration has secured lower drug prices, while affordability remains a voter concern ahead of the Nov. 3 midterm elections. Actual costs will vary depending on the medicines people use and their insurance coverage.