The firm’s results also showed pre-tax profits had risen from £17.2m to £27.4m - an increase of 59%.
Net inflows for the year to 31 March were £1.004bn (2017: £482m) and revenues were £77m (2017: £51m), an increase of 49%.
The company said the second interim dividend per share would be up from 11p in 2017 to 16p this year, which will be payable on 10 August.
The figure brought the total dividend per share for the financial year ending 31 March to 21p (2017: 15p), an increase of 40%.
John Ions, chief executive, said: “We have made substantial progress over the past year, posting impressive net sales and growth in AuM, a significant increase in revenue and profit, and broadened our fund management capability and client base.
“There have been net inflows of £1bn, the eighth successive year of positive sales and our AuM increased to £10.5bn.
“The Sustainable Investment team joined on 1 April 2017 and its AuM now stands at £3bn.
“The team has delivered strong performance in an area of increasing client focus.
“The new financial year has begun well, raising £202m for the launch of three funds managed by our Global Fixed Income team.
“This and good flows into other teams has now taken our AuM to £11.3bn compared to £6.5bn on 1 April 2017.”
Mr Ions said that the results demonstrated the “continued demand for active fund managers.”