Manufacturer Drug Rebate

A drug rebate is a payment from a pharmaceutical manufacturer to a PBM or health plan, made after the drug is dispensed, in exchange for preferred formulary placement, exclusion of competing drugs, or hitting utilization targets. Rebates are typically a percentage off the drug's Wholesale Acquisition Cost (WAC) and can range from single digits to 50 percent or more on heavily competitive categories like insulin, diabetes drugs, and PPI acid reducers.

The flow: the manufacturer sets a high WAC, the PBM extracts a large rebate for placing the drug on a preferred tier, the pharmacy dispenses at a price based on WAC (so the member's coinsurance calculates off the high number), and the rebate flows back to the PBM weeks or months later. Traditional PBMs historically retained a significant share of rebates as revenue; pass-through PBMs return the full rebate to the plan sponsor. This dynamic is why insulin list prices ballooned to $300 per vial while the net price to manufacturers stayed relatively flat — the gap became the rebate pool. Recent reforms (state laws, PBM transparency requirements, manufacturer direct-to-consumer programs) are slowly changing the model.

The takeaway: if you're a self-funded employer, know exactly what share of rebates you're receiving, when they're paid, and how they're calculated. A well-structured pass-through PBM arrangement should return 100 percent of rebates to the plan within a defined timeframe.