This study examined if greater insurer market power was associated with consistently lower negotiated prices within each hospital for 44 shoppable and emergency procedures, using price transparency data disclosed by 1,506 hospitals in metropolitan areas. We used multi-level fixed effects models to estimate the within-hospital variation in plan-level insurer-negotiated prices (from the largest insurer, the second largest insurer, other major insurers, and nonmajor insurers) and cash-pay prices as a function of insurer market power. For shoppable services, relative to nonmajor insurers, the largest, second largest, and other major insurers negotiated 23%, 16%, and 3% lower prices, respectively, while cash prices were 17% higher. For emergency room visits, while the largest insurers paid 5% less than nonmajor insurers, the second largest and other major insurers did not pay lower prices. Stratified analyses by type of shoppable services found varying magnitudes and patterns of price discounts associated with insurer market power.
Keywords: cash price; commercial health insurance; hospitals; negotiated price; price transparency.