Prior to his retirement, Gregson was the founding chief executive of HSBC Private Bank UK having joined Samuel Montagu which was ultimately HSBC Private Bank in 1989.
Before this he was managing director of Private Banking at Royal Trust Bank.
He is also non-executive director of Sand Aire, Aerides and Greenstone Carbon Management.
Cazenove Capital chief executive Andrew Ross says: “Marcus will be a very welcome addition to the board of Cazenove Capital, bringing with him considerable experience and expertise. He will help the board assess its strategy as it looks to grow Cazenove Capital, particularly with regard to its well respected wealth management business.”