Who controls the US insulin market?
Three manufacturers produce ~90% of world insulin; three PBMs process ~80% of US prescriptions — concentration on both sides that critics say enabled manufacturers to compete on rebate size rather than price, with PBMs incentivised to favour higher list prices.
Three manufacturers, Eli Lilly, Novo Nordisk and Sanofi, produce about 90% of the world's insulin. On the other side of the transaction are the three largest pharmacy benefit managers, CVS Caremark, Express Scripts and OptumRx, which together process roughly 80% of US prescriptions. PBMs decide which insulins appear on the formularies of health plans they serve and negotiate rebates from manufacturers in return. The FTC reported in 2024 that the largest PBMs are vertically integrated with major insurers and pharmacy chains. This concentration on both the supply and purchasing sides is central to the controversy: critics argue that rather than competing on price, manufacturers competed on the size of rebates, and PBMs had an incentive to favour higher list prices.