Orton, who is currently working as a deputy CFO, is also expected to become a member of the group management board (GMB) of the company.
The move comes as the current group CFO Richard McNamara is set to leave GAM Holding by the end of this year. McNamara has been serving in his current role since 2015.
Orton, who is a chartered accountant with over 25 years of experience, joined GAM Holding in May this year as deputy CFO.
During the span of her career, Orton has worked in various leadership and executive positions in registered asset management, insurance as well as banking and infrastructure companies.
GAM Investments CEO Peter Sanderson said: “I am delighted that Sally has been appointed Group CFO and would like to warmly welcome her to the Group Management Board.
“I would also like to thank Richard for his enormous contribution to GAM over the last seven years. He has been a great support to me personally and has worked tirelessly to help us manage through a challenging period.
“Sally has held the role of deputy CFO since earlier this year, has extensive experience in asset management and is an invaluable member of our senior team.”
Early last month, GAM Investments announced the appointment of Roland Mueller as senior investment manager for its Fixed Income division.
Mueller, who will supervise a number of global bond investment strategies and requirements for institutional customers, will operate from Zurich.