The Department of Justice (DOJ) is conducting a civil investigation of Partners HealthCare System Inc., a regional hospital and physician network founded in 1994 by Boston-based Brigham and Women's Hospital and Massachusetts Hospital, for possible anticompetitive behavior. DOJ investigators on April 19 sent letters to Partners, as well as to three of Massachusetts' largest health insurers, seeking documents that pertain to the nonprofit system's "contracting and other practices" in eastern Massachusetts. The DOJ wants to assess whether Partners wielded its considerable market power in violation of the Sherman Antitrust Act (i.e., to limit trade or artificially raise prices). FierceHealthPayer