Who is affected and how:

• Medicare beneficiaries: Likely improved access to local, independent, or small chain pharmacies because plans must accept any pharmacy that agrees to contract terms; could reduce travel or delivery delays for some enrollees.

• Retail pharmacies (independent, chain, and rural pharmacies): Directly affected—gain stronger rights to join Part D/MA–PD networks and new mechanisms to challenge denials or network exclusion; they may benefit from increased participation but may also face standardized contract terms set by plans and the Secretary.

• Pharmacy Benefit Managers (PBMs): Direct targets of new transparency, audit, and financial‑accountability rules; will need to deliver detailed reports, submit to audits, and may lose or be required to pass through some revenue streams—raising compliance, reporting, and possibly operational costs.

• Part D plan sponsors and Medicare Advantage organizations offering MA–PD plans: Must permit willing pharmacies (subject to contract terms), implement the Secretary’s standards, respond to pharmacy allegations, and integrate new contract, reporting, and audit requirements into operations—possible administrative and network‑management costs.

• Federal agencies (CMS / HHS): Increased administrative workload to develop standards, review PBM and plan submissions, run audits or authorize them, adjudicate allegations, and produce periodic public reports.

Likely downstream effects and tradeoffs:

• Patient access improvements are likely where pharmacies previously were excluded from networks, especially in underserved areas.

• Plans and PBMs may respond by adjusting network design, reimbursement rates, or other commercial terms; costs of compliance could be passed to plans, potentially affecting premiums or formulary designs.

• Increased transparency and enforcement could reduce some practices that limited pharmacy participation, but litigation or administrative disputes are possible as stakeholders adapt to new standards.

• Smaller pharmacies may still face practical challenges (e.g., negotiating terms, meeting administrative requirements) even with a statutory right to join networks, so outcomes will depend on how detailed standards and enforcement are applied.