The Department of Labor finalized a sweeping rule requiring pharmacy benefit managers to disclose detailed compensation information to self-insured employer clients. Regulators said the disclosures are expected to reduce drug costs for employers and workers by $22 billion over a decade. Under the rule, PBMs must share extensive data on payments they receive from drugmakers, pharmacies, and other parties, including negotiated rebates and so-called “spread” payments—the difference between plan reimbursement and what PBMs pay pharmacies. Disclosures must be provided when negotiating or renewing contracts and then every six months; employers can audit the information once a year. The rule takes effect July 2027 and includes consequences for noncompliance, including financial penalties and possible contract invalidation. Employers and policymakers largely backed the change, while PBMs opposed it, arguing it oversteps. The final rule is positioned as a structural shift in the U.S. drug supply chain by forcing greater visibility into rebate and fee mechanics—an issue central to biopharma’s pricing and contracting negotiations.