Treasury Group executive director David Cooper has resigned and will leave the company in December this year.
The backer of boutique fund managers will not replace Cooper.
"His departure completes a management transition planned by David and the board two years ago," Treasury chairman Mike Fitzpatrick said.
Cooper was Treasury's managing director from 2004 to 2008, after which he decided to focus on establishing partnerships with boutiques.
He has been working with the company to gradually hand over his responsibilities.
"I don't have any plans at this stage," Cooper told InvestorDaily.
Treasury chief executive Mark Burgess said the split was amiable and said he hoped to work with Cooper again at a later stage.
"He is a very talented guy and we hope to work together in some form of partnership in the future," Burgess said.
Cooper joined Treasury in 2002 as manager of strategic investments, when the company had only two boutique partners and less than $1 billion in funds under management (FUM).
He helped the company grow to eight partnerships and $15 billion in FUM.
Cooper will remain on the board of the company until the end of the year, after which Treasury will review its board positions.
