According to a London Stock Exchange notice, Chavasse will be on garden leave from 31 December 2016 and officially exit the company on 31 March 2017.
Chavasse is entitled to 12 months' notice and will therefore continue to receive his £293,550 salary, £35,426 per annum pension contribution and other benefits until the termination date.
Before joining Rathbones in 2001, he held roles at NatWest, Gartmore and Coutts. He took up his current role in 2012.
Chief executive Philip Howell said: "We would like to thank Paul for his significant contribution to Rathbones over many years. As a member of the group executive team and the board of directors, he has played an important role in helping steer the company through a period of growth and success. We wish Paul the best for the future".