Ray Dalio, the brain behind the world’s largest hedge fund, is stepping down from his role as co-chief executive, effective April 15.

In a letter sent to investors Wednesday Dalio, announced sweeping changes to Bridgewater Associates’ management team, which included his own decision to step down as co-CEO to focus on being co-chief investment officer.

“As I love markets, I’m excited about this change and expect to remain a professional investor at Bridgewater until I die or until those running Bridgewater don’t want me anymore,” Dalio said.

John Rubenstein, who had been serving as co-CEO, is leaving Bridgewater after being there for only 10 months.

“We mutually agree that [John Rubinstein] is not a cultural fit for Bridgewater,” Dalio said.

Dalio maintained that the changes were part of a broader transition plan that started soon after his sixtieth birthday that was expected to take as long as 10 years.

“Any organization run by a 60+ year old that says that it isn’t in transition is either naïve or disingenuous,” Dalio, 67, said.

Ten months ago, Dalio reassumed the role of co-CEO in addition to his duties as Bridgewater’s Chairman and co-CIO after then-co-CEO Greg Jensen stepped back from his role.

Under the new leadership structure, David McCormick will be joining Eileen Murry as co-CEO.

Late last year it was reported that the $160 billion hedge fund was building an algorithm to mimic the decision-making capabilities of some of his top managers.

Dalio frequently denied reports that the algorithm’s purpose was to “make Ray’s brain into a computer.”