The US Department of Labor finalized a sweeping rule requiring pharmacy benefit managers to disclose extensive details about compensation to self-insured employer clients. Regulators say the disclosures are intended to lower drug costs, with an estimated $22 billion impact over a decade. The rule covers compensation flows tied to drugmaker rebates and “spread” payments—where a PBM reimburses a pharmacy at one price while billing the plan at another—and mandates updates when contracts are negotiated or renewed plus periodic reporting every six months. Employers will be able to audit disclosures annually. PBMs face potential financial penalties and contract consequences for noncompliance, while employers and policymakers have largely backed the move as a way to reduce opaque pricing mechanisms in the US drug supply chain.