It began in May, with Humana Inc. (NYSE: HUM) publicly declaring it was exploring a sale. That announcement ignited the smoldering rumors that have been swirling around the healthcare industry since the beginning of 2015: Expect a lot of consolidation in the Managed Care sector this year. By mid June The Wall Street Journal reported that UnitedHealth Group (NYSE: UNH) approached Aetna Inc. (NYSE: AET) with an offer, and that Anthem (NYSE: ANTM) and Cigna (NYSE: CI) were engaged in merger talks. We checked our DealSearchOnline database to see how each of the top five spent on managed care targets since 1994. Check ’em out.   health insurer's M&A