In markets where buyers and suppliers negotiate, supplier costs, buyer willingness to pay, and competition determine only a range of potential prices, leaving the final price dependent on other factors (e.g., negotiating skill), which I call bargaining ability. I use a model of buyer demand and buyer–supplier bargaining, combined with detailed data on prices and quantities at the buyer–supplier relationship level, to estimate firm-bargaining abilities in the context of the coronary stent industry where different hospitals (buyers) pay different prices for the exact same product from the same supplier. I estimate that (1) variation in bargaining abilities explains 79% of this price variation, (2) bargaining ability has a large firm-specific component, and (3) changes in the distribution of bargaining abilities over time suggest learning as an important channel influencing bargaining ability.