Disadvantaging Rivals: Vertical Integration in the Pharmaceutical Market
2025-12-29
The pharmaceutical market has experienced a wave of vertical integration between pharmacy benefit managers (PBMs) and insurers in recent years. Using a unique dataset on insurer-PBM contracts, we document increasing vertical integration in Medicare Part D. Next, we evaluate the effects of a large insurer-PBM merger in 2015, assessing the trade-offs of vertical integration—harms to competition on the one hand and improved efficiency on the other. We find premium increases for rival insurers post-merger, consistent with vertically integrated PBMs raising costs through input foreclosure. We find no evidence of benefits to consumers of the merged firm from lower premiums. (JEL G22, G34, I13, I18, L22, L65)