In the Shadow of Antitrust Enforcement : Price Effects of Hospital Mergers from 2009-2016

We examine 558 hospital mergers during a period of increased antitrust enforcement. Using US data on commercially insured patients from 2009-2016, we estimate an average price effect of roughly 5% with a smaller effect for mergers later in the sample. Mergers between hospitals that were substitutes for patients, in unconcentrated insurance markets, and less likely to lead to efficiencies had higher price increases. Using administrative data on merger investigations, we estimate higher than average price increases for mergers selected for more detailed investigation and find no evidence of higher than average price increases for non-reportable mergers