The Medicare Part D standalone market is at risk of collapse, which could leave certain Medicare enrollees without access to affordable prescription drug coverage. With temporary measures currently stabilizing the Part D standalone market expiring, there is a need for near-term market intervention as we consider broader scale Medicare reforms.

Since the program’s launch 20 years ago, enrollment has shifted steadily from standalone Part D prescription-drug plans (PDPs) — available to beneficiaries enrolled in Traditional Medicare under Parts A and B — to Medicare Advantage prescription drug plans (MA-PDs) — bundled coverage available to Medicare Advantage enrollees under Part C.

This shift has been driven by structural market asymmetries — MA-PDs and PDPs operate within different financing and risk structures that create financial advantages for MA-PDs. The result has been a sharp contraction of the PDP market, with the number of plans available nationwide falling by more than 60% over the past five years. This has significant implications for Traditional Medicare beneficiaries, who rely on PDPs as to access prescription drug coverage. In particular, PDPs are often the only suitable option for individuals living in rural areas where MA-PDs are not available, or individuals with complex health needs who require the flexibility of PDPs.

In June 2026, Camber convened subject matter experts across Medicare, health economics, federal health policy law and process, commercial insurance, and beneficiary experiences, to co-design potential policy options to address these market challenges. Our research considers three policy pathways to strengthen access to prescription drug coverage, outlining key considerations, implementation feasibility and expected market impact for each.

Read more in our white paper, Preventing Collapse: Policy Solutions to Strengthen Medicare’s Standalone Part D Plan Market, and Health Affairs article, An Old Idea Whose Time Has Come: Why Medicare Needs A Federal Backstop For Part D.