Pharmacists for Fair Reimbursement What your state's PBM laws actually mean for community pharmacies
Explainer Updated June 15, 2026

NADAC, WAC, AWP: what's the difference between drug-pricing benchmarks?

These three benchmarks measure different things. NADAC (National Average Drug Acquisition Cost) is CMS's estimate of what retail pharmacies actually pay for a drug, built from a voluntary monthly survey of pharmacy invoices. WAC (Wholesale Acquisition Cost) is the manufacturer's published list price to wholesalers — a statutory term, and explicitly not net of rebates or discounts. AWP (Average Wholesale Price) is a published 'sticker' benchmark from commercial compendia that, by the government's own account, is neither an average nor a price wholesalers actually charge. Only NADAC is built to reflect real acquisition cost, which is why state reimbursement floors increasingly anchor on it.

Key findings

  • List price, not net priceWAC is defined in federal statute as the manufacturer's list price to wholesalers, 'not including prompt pay or other discounts, rebates or reductions in price' (42 U.S.C. § 1395w-3a) Source: 42 U.S.C. § 1395w-3a
  • Not an actual sale priceThe GAO found AWP 'may be neither an average nor what wholesalers charge,' with no requirement that it reflect any actual saleAs of 2001. Source: GAO-01-1142T
  • Built from real invoicesNADAC is built from a voluntary monthly survey of retail community pharmacies' actual invoice purchase recordsAs of current. Source: CMS — Retail Price Survey (NADAC)

Three benchmarks, three different things

The terms get used interchangeably, but they measure different points in the supply chain. WAC (Wholesale Acquisition Cost) is the manufacturer’s published list price to wholesalers — a defined statutory term that explicitly excludes “prompt pay or other discounts, rebates or reductions in price,” so it overstates what anyone actually nets. AWP (Average Wholesale Price) is a published benchmark from commercial compendia (such as First Databank and Medi-Span); critics call it “ain’t what’s paid,” because, as the GAO put it, it “may be neither an average nor what wholesalers charge.” NADAC (National Average Drug Acquisition Cost) is the outlier: CMS’s estimate of what retail pharmacies actually pay, built from real invoices. See the NADAC explainer for how it is calculated.

Why NADAC is built differently

NADAC comes from a voluntary monthly survey in which retail pharmacies submit their actual invoice purchase records — the price paid to acquire a drug. That is a fundamentally different construction from WAC and AWP, which are list values a manufacturer or compendium publishes and the seller can influence. Federal oversight has repeatedly flagged the gap: the GAO found AWP carries no requirement to reflect any actual sale, and HHS OIG analyses documented large, systematic differences between published prices and prices actually paid. NADAC’s value is that it is independent, survey-based, and grounded in transactions rather than list.

Why states anchor floors on NADAC

This is why state programmes increasingly set pharmacy reimbursement against NADAC rather than AWP or WAC. The 2016 federal Covered Outpatient Drug rule replaced “estimated acquisition cost” with “actual acquisition cost,” and CMS treats NADAC as a benchmark that meets that standard, paired with a professional dispensing fee. A reimbursement floor built on an independent measure of real cost is harder for any single seller to inflate than one built on a published list price. The state tracker shows which states have done this and how.

Sources

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