Fisher stressed that while Couillault was leaving at a difficult time for the financial industry, his decision was "in no way linked to current fund performance or investment decisions".

"It's not a rift," she added. "It's just Warren has decided it's time to think about things and do something else."

Fisher said she did not know what Couillault's future plans were, only that he would not be in the market for the next year. He has sold his 27% stake in the company to Fisher and Hugh Fisher.

Couillault has been with the high-profile funds manager for six years, jointly managing the New Zealand portfolios with Fisher.

Last week, rumours swirled when Couillault stepped down as a director after his authority to trade for Fisher Funds was removed, although Fisher said that was normal when there was a management change.

She will continue to manage the local portfolios alone, and noted that because the New Zealand Growth Fund was currently closed, Couillault would not be replaced soon.

"It's always disappointing to lose a member of the team but following Warren's recent decision to play a less significant role in the company and to sell his shareholding, Warren and the board agreed that it was in the best interests of the company for him to resign as chief investment officer and portfolio manager of the New Zealand portfolios," she said in a statement.

John Wells will return to the board as an independent director.