Former Invesco executive Lewis Bearman has resigned as chief of IOOF-controlled Perennial Investment Partners, even as the parent group conducts a review of the investment management firm's operational structure.

Mr Bearman, the former head of operations at Invesco who joined Perennial more than a decade ago, is departing at the end of June. An IOOF spokeswoman said Mr Bearman is on leave until his exit, and that he is leaving for personal reasons. His departure marks the end of his 11-year tenure at investment house Perennial, which contributes about a third of listed wealth manager IOOF's profits.

It is understood Mr Bearman tendered his resignation in April.

IOOF has not publicly announced his departure, but it is understood that asset consultants and Perennial clients were informed of his upcoming exit at the time of his resignation.

The company is reviewing Perennial's operational structure in the wake of the departure.

''There is a review under way to ensure the boutiques continue to receive the support they need for the business,'' the spokeswoman said.

It is unclear whether IOOF will appoint a new chief executive to replace the outgoing CEO.

The pending departure comes as acquisition-hungry IOOF continues to strike deals across the financial services sector.

Earlier this month, Australia's largest credit union, Credit Union Australia, struck a deal to offload its financial planning arm to Bridges Financial Services, which is part of the IOOF suite of businesses.