Inflows into the unit trusts run by Rathbone's drove growth in the assets under management (AUM) last year,
The company said the unit trust part of the business managed £5.3bn at 31 December 2017, an increase of 32 per cent on the number to 31 December 2016.
Net inflows for this part of the business were £272m, more than double the £125m of net inflows for the same period in 2016.
During the year the Rathbone Ethical Bond fund grew to more than £1bn.
Total assets under management for the company at the end of December 2017 were £39.1bn, an increase of 11.9 per cent.
Stuart Duncan, analyst at Peel Hunt, said the update "beat expectations" and he has upgraded his view of the shares of Rathbone to a buy, from his previous forecast of hold.
Rathbone Brothers PLC share price is up 6p to £25.38 at the time of writing.
Mr Duncan said his target price for the shares is £28.