http://healthaffairs.org/blog/2016/06/21/health-affairs-study-on-hospital-profitability-gives-us-some-important-factors-to-watch-going-forward/

Bai and Anderson report two profitability-related factors that reflect the effect of hospital consolidation trends: regional power and system affiliation. Regional power refers to hospitals that face less competition in their local markets, while system affiliation indicates hospitals that are part of multi-hospital systems. Both are associated with higher profitability in their study.

More and more hospitals across the country are joining systems that operate outside their local markets. This is due, in part, to the fact that antitrust regulators have limited local market mergers but have not, in general, adapted their models of hospital market competition and antitrust to address non-local mergers. As a result, hospitals in some instances are able to join systems, gain market power, and raise their prices without necessarily improving quality or service. My own research in this area (forthcoming inINQUIRY) shows that hospitals that are part of the largest multi-hospital systems in California were able to negotiate price increases that are consistently well above all other hospitals in that state.