A maximum allowable cost (MAC) is the ceiling a pharmacy benefit manager (PBM) will reimburse for a given generic drug. When that ceiling is set below what a pharmacy actually paid its wholesaler, the pharmacy dispenses at a loss. A MAC appeal is the mechanism for challenging that specific reimbursement.
What an appeal generally involves
The details are set by state law and by each PBM’s own procedure, but the common shape is:
- A filing window. Many state laws require the PBM to accept an appeal within a set number of business days of the claim — the exact window is one of the things that varies most by state.
- Evidence of acquisition cost. The pharmacy typically must show what it paid (for example, a wholesaler invoice) to demonstrate the MAC is below cost.
- A decision and a remedy. If the appeal succeeds, the law may require the PBM to adjust the MAC, and in some states to do so for other similarly situated pharmacies — not just for the single claim.
Why the state rules matter
Because the filing deadline, the evidence standard, and the remedy all turn on state law, the practical answer to “how do I appeal?” depends on where the pharmacy is. The State Tracker sets out, per state, whether an appeals procedure is required and the reimbursement floor it sits alongside. For the precise procedure, a pharmacy should always check the current statute and the specific PBM’s appeal instructions.