WHEN JOHN CONNAUGHTON left consulting for private equity (PE) by joining Bain Capital in 1989, “my mentors counselled against it,” he recalls. “They said it wouldn’t last.” Now he heads Bain’s global PE business. He has helped assemble such huge deals as the formation of IQVIA, a life-sciences group valued at $47bn. Bain Capital manages $155bn of assets. The target for its 13th buy-out fund last year was $9bn; it closed just short of $12bn.