This bill addresses pharmacy benefit managers (PBMs), pharmacies, and prescription drug pricing. A pharmacy benefits manager acts as a middleman between insurers, pharmacies, and drug manufacturers, assisting in negotiating drug prices and establishing a list of covered drugs. The bill prohibits a PBM from treating any pharmacy or pharmacist unfairly. Starting from July 1, 2024, it requires all related contracts executed, adjusted, or renewed to use a pass-through pricing model, which is a method where payments from third-party payors to PBMs for prescription drugs are equal to the payments the PBMs make to pharmacies. It also excludes the allowance of spread pricing, which is a practice where a PBM charges a third-party payor more for prescription drugs than the amount the PBM pays to the pharmacy for the same drugs, unless the entire amount caused by spread pricing is passed through by the PBMs. Furthermore, the bill mandates PBMs to provide a mechanism for pharmacies to appeal a maximum allowable cost (MAC), which refers to the maximum amount that an insurer will pay a pharmacy for a specific prescription drug.