Mark Gregory will become CEO of Merian Global Investors following a decision by Richard Buxton to step down.
The change will become effective following regulatory approval, a spokeswoman said.
Mr. Buxton will remain with the firm as head of U.K. equities and manager of the Merian U.K. Alpha fund. He will also step down from the executive committee once he has handed over his CEO responsibilities.
The firm has £31.6 billion ($40.2 billion) in assets under management.
Mr. Gregory is currently an independent non-executive director, a position he's held on Merian's board since October. He has worked on developing the firm's strategy and most recently chief financial officer at Legal & General Group.
The firm underwent a buyout in June by its management team and strategies operated by private equity firm TA Associates. It was also rebranded from Old Mutual Global Investors.
"With the management buyout and rebranding complete, I believe this is the appropriate time for me to hand over the CEO role," Mr. Buxton said in a news release. "I am completely committed to the business, and I will continue to be involved in its development in my role on the board. Having known (Mr. Gregory) for many years, I am absolutely convinced that he is the right person to take the business forward."