This bill significantly amends the Employee Retirement Income Security Act of 1974 (ERISA) by explicitly deeming pharmacy benefit managers (PBMs) as fiduciaries for group health plans. This fiduciary status applies to PBMs that maintain prescription drug networks or formularies, purchase prescription drugs, or engage in activities such as negotiating rebates, processing claims, or performing utilization review for group health plans. By classifying PBMs as fiduciaries, the bill extends ERISA's protections and duties of loyalty and prudence to these entities, ensuring they act in the best interest of plan participants. To further enhance transparency and accountability, the legislation requires PBMs and third-party administrators to provide comprehensive disclosures of all direct and indirect compensation they expect to receive for their services. It also clarifies that a covered service provider cannot be the responsible plan fiduciary for disclosure purposes, except when a PBM sponsors its own employee plan. Crucially, the bill prohibits PBMs from being indemnified or otherwise relieved from liability for any breaches of their newly established fiduciary responsibilities, making any such contractual provisions void as against public policy. These amendments will apply to plan years beginning at least 12 months after the bill's enactment.