Most Favored Nation pricing in pharmaceuticals requires drug companies to offer U.S. government programs the same or lower price than the lowest price charged in any other country for the same drug. The concept originates in international trade law, where MFN treatment means equal treatment for all trading partners. In Trump's 2026 pharmaceutical tariff proclamation, companies that negotiate approved MFN pricing agreements with the Secretary of Commerce can avoid or reduce the 100% tariff rate — using trade penalties as leverage to extract domestic drug price concessions.