Nothing but blue skies? Not-for-profit health systems try to soar over a slipping Columbia.

With Columbia/HCA Healthcare Corp. sitting on the sidelines, a newly aggressive not-for-profit hospital sector is stepping up its merger and acquisition activity. Since Richard Scott resigned as Columbia's chief on July 25, the company hasn't announced a single acquisition. Meanwhile, during that span, 40 not-for-profit systems have announced deals involving 50 hospitals.