Physician Practice Consolidation Driven By Small Acquisitions, So Antitrust Agencies Have Few Tools To Intervene.

The growing concentration of physician markets throughout the United States has been raising antitrust concerns, yet the Department of Justice and the Federal Trade Commission have challenged only a small number of mergers and acquisitions in this field. Using proprietary claims data from states collectively containing more than 12 percent of the US population, we found that 22 percent of physician markets were highly concentrated in 2013, according to federal merger guidelines. Most of the increases in physician practice size and market concentration resulted from numerous small transactions, rather than a few large transactions. Among highly concentrated markets that had increases large enough to raise antitrust concerns, only 28 percent experienced any individual acquisition that would have been presumed to be anticompetitive under federal merger guidelines. Furthermore, most acquisitions were below the dollar thresholds that would have required the parties to report the transaction to antitrust authorities. Under present mechanisms, federal authorities have only limited ability to counteract consolidation in most US physician markets.