Is NADAC the same as my PBM cost?

No. NADAC is the average price retail pharmacies pay wholesalers — published weekly by CMS. It is not what your PBM bills your plan.

Your PBM cost is set by your contract, typically AWP-X% (Average Wholesale Price minus a percentage discount) with a MAC (Maximum Allowable Cost) list overlay on generics, plus dispensing fees. The gap between NADAC and what your PBM bills you is called spread. On legacy contracts with MAC pricing on generics, that spread commonly runs 100 to 400 percent on high-volume molecules.

The leak report quantifies the molecule-by-molecule exposure; an actual NADAC pass-through contract is how you collect it at renewal time.