But it will also sell 24.99 per cent of Fisher Funds to TA Associates - a global private equity firm with fund management experience.
TA Associates would then increase its stake to 34 per cent after gaining regulatory approval.
No sale price figures have been mentioned but Fisher Funds has grown substantially in recent years with the growth of KiwiSaver.
It is the fifth largest KiwiSaver provider in the market.
Fisher Funds has over 270,000 clients and $7 billion under management.
Carmel Fisher said she and Hugh were pleased to hand over the future control of their business to a strong and stable entity.
"The TSB Community Trust have been a very supportive shareholder over the past four years, and I know they share our passion for excellent client service.
"Hugh and I are proud to have been able to help so many New Zealanders with their wealth and retirement savings over the past two decades, and we're pleased to hand over the future control of our business to a strong and stable entity committed to delivering excellent investment returns and great client service into the future."
Carmel Fisher will stay as a director on the board.
The settlement will go through this month.