Ruffer chief executive and chief investment officer Henry Maxey is to relinquish the former role, with a replacement being appointed who can give "full time attention" to developments at the company.
Clemmie Vaughan, who has been at Ruffer for 12 years and leads its private client department, will become chief executive of the firm at the start of April.
Mr Maxey, who has held both roles for five years, will continue to lead the firm's investment process as chief investment officer.
Jonathan Ruffer, who remains as executive chairman, said he was "right chuffed" by the appointment.
Mr Maxey said: "The organisational challenges of our growth demand full time attention.
"At the same time, releasing more of my time for investment reflects the absolute importance of sound investment judgement within client portfolios."
Mr Ruffer added: "This is Ruffer’s third chief executive since it started 22 years ago. Once again, it is an internal appointment, and a wholly appropriate development."