Replacing the duo, Kames has announced that Stephen Snowden and Adrian Hull have been appointed as co-heads of fixed income.
Snowden, who is currently head of credit at Kames, will continue in this role and as co-manager of the Kames Absolute Return Bond Fund, alongside Colin Finlayson, and the Investment Grade Bond and Investment Grade Global Bonds Funds, alongside Euan McNeil.
Hull meanwhile is currently a senior fixed income specialist on the team, carrying 27 years’ experience.
In other fund duties, Kames said that Juan Valenzuela will continue to co-manage the Kames Strategic Bond Fund and become co-manager of the Kames Strategic Global Bond Fund, for which Roberts and Milburn (pictured) were co-managers. Alex Pelteshki, who joined Kames in 2014 from ING Financial Markets, has been appointed co-manager of the funds.
Iain Buckle will continue as co-manager of the Sterling Corporate Bond Fund, which Roberts was also a co-manager of. Rory Sandilands, who joined Kames in June 2016 from Goldman Sachs, will become co-manager.
David Ennett and Stephen Baines will continue to run the Kames High Yield Bond Fund, which Milburn was a co-manager of. Ennett will be joined by Jack Holmes as co-manager of the High Yield Global Bond Fund, which Milburn was also a co-manager of.
Martin Davis, chief executive of Kames, said: “I would like to congratulate Stephen and Adrian on their new roles and believe with their experience and expertise we are well placed to continue to grow our business and maintain our impressive record in managing fixed income investments for clients.
"I would also like to thank both David Roberts and Phil Milburn for their contribution to our business, and to wish them every success in their future careers.”
Reacting to the news, Ryan Hughes, head of fund section at AJ Bell Investments, said: “While the news of the departure of both Roberts and Millburn is a surprise, it should be remembered that Kames has a very strong team that is highly experienced.
"Kames have been excellent over the years in building the reputation of all in the team so the names of the managers taking on their responsibilities should be well known to many investors.
“In Snowdon, the fixed interest team will now be led by a fund manager who has a great long term track record and is someone I have invested with for many years. I expect very little change in the investment approach and while this is clearly a big change, I would certainly caution against investors making quick decisions given the strength of the team."