Enrollment in Medicare Advantage, the private plan alternative to traditional Medicare, has increased steadily over the past two decades, and since 2023, more than half of eligible beneficiaries have enrolled in Medicare Advantage. Amidst this growth, an increasing number of beneficiaries are enrolling in special needs plans (SNPs), especially since 2018, when SNPs became a permanent part of the Medicare Advantage program. SNPs now account for 21% of all Medicare Advantage enrollees, compared with just 13% in 2018. The increase in the share of Medicare Advantage enrollees in SNPs also means that SNPs contribute disproportionately to the growth in Medicare Advantage enrollment. For example, between 2024 and 2025, growth in SNPs comprised nearly half (48%) of the total increase in Medicare Advantage enrollment.
In recent years, the Centers for Medicare and Medicaid Services (CMS) has made several changes to requirements for D-SNPs and other Medicare Advantage plans, which may affect insurer decisions about the types of plans they offer and promote. To better understand the growing role of SNPs in Medicare Advantage and the potential implications for beneficiaries of changes to SNP and Medicare Advantage plan requirements, this brief examines SNP enrollment patterns and trends using recent Medicare Advantage enrollment data published by CMS.
Key Points:
- Since 2018 when SNPs became a permanent part of the Medicare program, SNP enrollment has tripled, rising from 2.6 million to 7.3 million, an increase of nearly 4.7 million enrollees.
- Through 2024, growth in SNPs was driven by an increase in enrollment in D-SNPs, which grew from 2.2 million enrollees in 2018 to 5.8 million enrollees in 2024, comprising more than 90% of SNP enrollment growth over that time.
- C-SNPs comprised 75% of total SNP enrollment growth between 2024 and 2025, in contrast to prior years, where enrollment growth was mainly in D-SNPs. In 2025, C-SNP enrollment increased by 476,300 new enrollees, triple the increase in D-SNP enrollment (159,400 new enrollees).
- A small share of SNP enrollees, just 14%, are in plans administered by non-profit insurers. SNP enrollment is highly concentrated among a small number of large national carriers, with UnitedHealth Group and Humana plans comprising over half (54%) of total SNP enrollment. UnitedHealth Group accounts for half of all C-SNP enrollees.
- The acceleration of C-SNP enrollment growth and slowing of D-SNP enrollment growth coincided with implementation of new rules for D-SNPs requiring greater integration between Medicare and Medicaid. C-SNPs are not required to have a similar level of integration.