Luca Vaiani, who was also a partner at the firm, was responsible for the Melchior Global Multi-Asset portfolio, which he has took over after joining the group in September 2012.
Previously he worked for Fondaco SGR in Turin, Italy.
The Melchior vehicle was borne out of the merger of the Melchior Global Balanced fund, run by Rupert Caldecott, and the Melchior Global Active fund managed by founder Andrew Dalton.
The miniscule fund has haemorrhaged assets in recent years, falling from some $50m in 2013, to just $7.4m (£4.78m) in size by the end of June.
A Dalton Strategic Partnership spokesman said: “I can confirm Luca has left the business by mutual consent. However, the fund is still being managed to the same absolute return remit, but by the global equities team headed by Nick Mottram.”
Over the past three years, the fund is up 9 per cent in sterling terms, according to numbers from FE Analytics.