Meera Patel, a senior analyst at Hargreaves Lansdown, said the recent divestment of stakes in joint ventures Hexam Capital and Argonaut Capital Partners had fuelled worries.
She said: “Although Ignis says it remains committed to supporting Cartesian and continues to hold a 50% equity stake in the business, we believe this is nevertheless unsettling.
“We would like to see Ignis take steps to attract new investments into this fund as a sign of its commitment.”
Another factor behind the removal of the Cartesian fund was concern over the workload of manager Jeremy Hall, who also manages the UK Opportunities fund.
The analyst said the departure of founding partner David Stevenson would result in an increased workload for Hall.
Patel added: “This departure means that the team of three is losing a key member and, with no immediate plans to hire a replacement, we are concerned they will be left under resourced.”
However, Patel said Hargreaves Lansdown remained supporters of Cartesian, describing it as a “high quality outfit”.
She said investors should not consider selling out of the fund it it continues to meet investors’ objectives.