The board of the Securities Trust of Scotland has decided to replace Martin Currie with Troy Asset Management as its investment manager and PATAC as the alternative investment manager, company secretary and administrator.
The news follows an "extensive review" conducted by the board of the £207m trust.
The new arrangements will see senior fund manager James Harries take over the management of the trust in October, supported by Tomasz Boniek and the wider Troy team.
The news follows the announcement that Mark Whitehead, who was running the trust, will leave Martin Currie in December after five years with the firm.
Chairman John Evans said: "The directors of Securities Trust of Scotland are delighted to announce the appointment of Troy Asset Management as the new investment manager of the company and PATAC as the AIFM and company secretary.
"The board's objective throughout the recent search process was to find a team with the resources, record and skills to continue to achieve the company's objectives.
"We believe that in PATAC, Troy, James and Tomasz we have an excellent outcome and we look forward to a long and successful working relationship with all of them."
Sebastian Lyon, CIO at Troy, said: "Troy is delighted to have been appointed investment manager of Securities Trust of Scotland, as this appointment presents us with the opportunity to build upon our existing track record of managing investment trusts."
Harries added: "We are very much looking forward to working with the board of Securities Trust of Scotland and providing rising income and long-term capital growth for shareholders."
The new manager will seek to "achieve rising income and long-term capital growth through patient and disciplined capital allocation, seeking out high quality income by investing in exceptional companies that the fund managers believe are attractively valued, with strong management teams, able to sustain growth at high returns on capital, in a high conviction, low turnover portfolio of approximately 30 to 50 stocks".
The appointment of the new manager is expected to reduce costs for shareholders, with Troy waiving the management fee payable for a period of 12 months and making a "significant ongoing annual contribution" to the costs of PATAC's services.
The annual management fee taken by Troy will be 0.65% on net assets up to £750m, 0.55% on assets between £750m and £1bn and 0.50% on anything above this.
The board is also introducing a discount control mechanism, which will see the trust ensuring that, under normal market conditions, the shares trade consistently close to NAV, in an effort to protect shareholders from significant discounts.
Evans said: "The efficient use of the discount management policy has allowed the two investment trusts currently managed by Troy to show significant growth through consistent share issuance. The board is optimistic that such success will be replicated with Securities Trust of Scotland under its new management arrangements."