A recent Office of Inspector General (OIG) report investigating the impact of vertical integration in Medicare Part D highlights significant transparency gaps in the current market. The OIG launched the evaluation due to concerns regarding potential anticompetitive behaviors and their effect on independent pharmacies, citing that in 2023, just six of the eleven identified vertically integrated organizations accounted for roughly 82 percent of the $275.9 billion in total Part D spending.
While the report found that net drug costs were similar across all sponsors, noting that enrollees in vertically integrated plans often pay lower monthly premiums but significantly higher out-of-pocket costs, the OIG emphasized that the full impact of vertical integration remains unknown by data limitations regarding pharmacy payment adjustments. Although vertically integrated sponsors appeared to pay their own pharmacies slightly less than independent ones, the OIG could not fully account for subsequent payment adjustments that often reduce final pharmacy reimbursements. Ultimately, the report suggests that recent changes to Part D market requirements may improve payment transparency and allow for more accurate future assessments. Read the full OIG report.
Last Updated on June 12, 2026 by Aimed Alliance
