Rebate Aggregator

A rebate aggregator is a company that sits between drug manufacturers and PBMs to negotiate and collect rebates. The three largest PBMs each own one: Zinc Health Services (CVS Caremark), Ascent Health Services (Cigna's Express Scripts, based in Switzerland), and Emisar Pharma Services (UnitedHealth's OptumRx, based in Ireland). The aggregator negotiates the rebate with the manufacturer, keeps a fee, and passes the rest to the PBM, which then passes some share to the employer's plan.

The reason this matters to a plan sponsor is arithmetic. If your PBM contract promises you "100 percent of rebates," the question is 100 percent of what. If the aggregator kept a fee before the money reached the PBM, that fee was never a rebate in the contract's definition, and you never see it. The Federal Trade Commission's 2024 interim report on PBMs called out this structure specifically, noting that the aggregators are placed offshore and that their fees are not disclosed to plan sponsors. I have read plenty of PBM contracts, and the rebate definition is the paragraph that decides whether the promised pass-through means anything.

The takeaway: when you review a PBM contract, find the definition of "rebate" and ask whether it includes every dollar the manufacturer paid anyone in the chain, including the aggregator. If it does not, ask for it to.