Joint senior partner at Baillie Gifford Charles Plowden is set to retire next year, having served nearly 40 years with the firm.
His departure, which is set for 30 April 2021, will see Malcolm MacColl step up to joint senior partner, while Helen Xiong will join the Global Alpha Strategy at the end of May.
Xiong, who has worked closely with the strategy for eight years, will remain joint manager of the Baillie Gifford US Growth trust, while senior analyst for US equities Dave Bujnowski will replace her as one of four managers on the Baillie Gifford American fund on 1 June.
Plowden will continue to manage the Global Alpha Strategy, the Global Alpha Growth fund and Monks until his departure, after which Spencer Adair will step up to become the lead manager of the Monks investment trust. MacColl will continue as both manager of the Global Alpha Strategy and deputy manager of Monks.
Having joined Baillie Gifford's UK equities team in 1983 as an investment manager, Plowden helped to develop the firm's institutional UK equity capabilities and latterly led the team.
He has worked in the Global Alpha Strategy since its inception in 2005 and became joint senior partner the following year with responsibility for the firm's investment department.
Plowden has been a vocal supporter of active asset management in recent years, notably criticising the "oversimplification" and "flawed analysis" used in coverage of the active versus passive management debate.
A key achievement of his career in recent times was turning around the lacklustre performance of the Monks investment trust, which Plowden turned into a top performer among peers after being made manager in 2015.
Senior partner Andrew Telfer, fellow senior partner, said: "Charles joined Baillie Gifford 37 years ago and has been at the heart of the firm's growth, notably in the UK Equities Team, the Global Alpha Strategy and as a leader of the whole investment department.
"This is a remarkable achievement in today's age. Most importantly, during this period, he has generated excellent investment returns for clients."
Plowden added: "By next April I will have reached my 60th birthday and spent almost 38 years at Baillie Gifford, 15 of them as senior partner.
"While I have enjoyed every minute, it is time for me to move aside and allow others to step up. I am immensely proud of Baillie Gifford and have every confidence that the firm will continue to add significant value for its clients and build on its distinctive culture."