The "Reducing Drug Prices for Seniors Act" proposes to amend Medicare Part D by requiring that drug coinsurance be calculated based on a drug's net price instead of its list price . This change is set to take effect for plan years beginning on or after January 1, 2026, specifically for costs incurred above the annual deductible and below the annual out-of-pocket threshold. The bill defines net price as the negotiated price of a covered Part D drug, after accounting for any manufacturer-provided price concessions. By mandating this calculation, the legislation aims to ensure that beneficiaries' out-of-pocket costs more accurately reflect the actual discounted price of medications, thereby potentially lowering their financial burden. This adjustment would apply to drugs subject to coinsurance rather than a copayment.