Insurer shall pay for services rendered within 45 days upon receipt of clean claim. If claim is denied, insurer must provide a reason for denying the claim and what, if any, additional information is required within the time necessary to pay a claim. If a clean claim is not paid within the 45 days it is subject to a 1.5% per month interest charge, up to a maximum of 18 % per year.

Link to Existing Law: Chapter 141 of the Acts of 2000 section 20

This Prompt Pay law is applicable to HMOs. While PBMs are not specifically mentioned, they are likely included as an agent for an HMO.