A changing of the guard is looming for the largest US bank, private investment firm, and asset manager. It’s a once-in-a-generation power shift at three companies that has the potential to make waves on Wall Street.

Chief executives Jamie Dimon of JPMorgan Chase, Steve Schwarzman of Blackstone, and Larry Fink of BlackRock have not indicated that their departures are imminent. They are, though, well past what was once considered a typical retirement age and have been either messaging that they are approaching their exits, promoting their slates of likely successors, or both.