Bill Harer, head of fixed income at Canada Life Investments, will retire at the end of March 2018.
He was both head of fixed income credit research and manager of the £215m Canlife Corporate Bond Fund.
Mr Harer has worked at the firm since 1982 and jointly managed the corporate bond fund since 2012.
His fund management responsibilities will be taken over by Kshitij Sinha.
Roger Dawes, head of fixed income portfolio management at Canada Life said: "Kshitij is a fund manager with significant experience in the fixed income markets and a proven performer.
"Canada Life Investments has a strong track record of promoting from within the business and this will ensure a seamless transition for our investors."
Mr Sinha is currently co-manager on a number of global bond mandates, alongside senior fund manager, David Arnaud, including the £210m LF Canlife Global Bond Fund. He will continue to work on those funds.
He joined Canada Life Investments in 2016 as a fund manager. Before this he traded European investment grade bonds as a market maker at Morgan Stanley.