Apollo Global Management Inc. Chief Executive Officer Marc Rowan’s potential next act as US Treasury secretary would thrust the firm he co-founded into an entirely new era of leadership. It may also help unlock trillions of dollars for its hottest business line.

In the roughly three years since co-founders Leon Black and Josh Harris left the company, Rowan has helped transform Apollo from a feared distressed-debt investor into a buzzy, money-spinning lending machine that rivals Wall Street’s banks. He also ushered in an era of stability and prosperity after a tumultuous power struggle. During his tenure, assets have soared to $733 billion, and its stock has more than tripled.