Rob Burnett, manager of the £331m Neptune European Opportunities fund, has left to set up his own business after 16 years with the asset manager.
Thomas Smith, manager of the firm's £33m Latin America fund, will take over the European Opps fund.
Burnett (pictured) will continue to work on the fund this month during the handover.
He joined Neptune in June 2002 before being appointed manager of the European Opps fund in May 2005.
Neptune said in a statement: "Rob Burnett is leaving Neptune to set up his own company.
"It is entirely understandable that this is the right moment in his career to pursue this entrepreneurial path and after many years of valued service to Neptune and our clients we wish him all the best in this endeavour.
"Rob will be at Neptune until the end of the year. He continues to manage the fund for now and will be working closely with Tom on the handover during December."
According to FE, the fund has returned 30.8% over the past three years versus 28.3% for the IA Europe Excluding UK sector, as at 3 December.
The firm has experienced a number of changes in recent times with head of UK sales Daniel Lee leaving after just one year in October and former J.P. Morgan Asset Management veteran Mike Parsons joining as head of global sales.
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