Tucker was manager on the firm’s £57.3m Global Equity Fund of Funds and £35.9m Global Diversified Fund of Funds, both launched as part of Sarasin’s first foray into multi-manager in 2012.
He joined the firm in 2007, and took on the role as senior fund analyst in 2011.
The funds continue to be led by Sam Jeffries, with fund manager Lucy Walker and team assistant Jamie Fletcher.
The Third Party Funds team will also be strengthened by the arrival of Alistair Campbell as a fund analyst on 1 October from SG Hambros.
A statement from Sarasin & Partners said: “Oliver has added significant value to the development of our third party fund selection process and we wish him continued success in his future career”.