Hospital system market share and commercial prices: a cross-sectional approach using price transparency data.

Background: The goal of this study is to estimate the association between hospital system market share and negotiated prices. Hospital system consolidation has led to many highly concentrated markets where systems can leverage their market share to negotiate higher commercial prices. Recently, the Centers for Medicare & Medicaid Services, under its Transparency in Coverage initiative, required health insurers to release all negotiated commercial prices, providing, for the first time, publicly available, nationally representative data on commercial rates.