The seven-partner firm, which opened its doors last month and which has remained in the same building as its old firm, has appointed Peter Rintoul as its investment director.
Rintoul, a chartered accountant who originally worked for Gartmore, has another accountant and four investment administrators on his team.
Partner Douglas Connell said: "This is a new development. It is not something that Dundas & Wilson did. We have been planning to do it for some time."
The practice will focus on advising probate clients, trusts and charities, and will reflect what Connell said was "an increasing demand from clients to offer a total service".
Members of the firm have been building its investment business since February, while they were still part of Dundas & Wilson. However, according to Rintoul, it has not signed any client agreements yet.
"We are ready to move now but for a variety of reasons we want to make sure that everything is in order," he explained.
It has installed a Pilgrim system for use throughout the firm and an LSD system for its investment management department.
Rintoul said the investment department would be a modest size to begin with but would become as "big as necessary". He added that the intention was to give discretionary advice to the "substantial private client base that already exists".
Turcan Connell will be the fifth major firm to be offering investment management services in Scotland.