Aberdeen, head by chief executive Martin Gilbert, said one institutional customer pulled £4.2bn on their own from the group’s equity products, driving the total amount withdrawn by customers to £8.8bn.
It did not name the customer, but said they still remained a client of the FTSE 100 group.
Assets under management, which measures how much money the fund invests on behalf of customers in stocks, bonds and property, dipped 0.6 per cent to £322.5bn.
This came despite its roster of funds adding £11.3bn to the value of assets. The other factor weighing on its asset base was foreign exchange rates, which reduced assets by a further £5.3bn.
Gilbert said in a statement: “Encouragingly, investor sentiment towards Asia and emerging markets recovered somewhat during the quarter.”
The results were the first posted since Aberdeen bought smaller rival Scottish Widows Investment Partnership (Swip) from Lloyds Banking Group earlier this year.
Aberdeen saw £3.3bn leave Swip-related funds during the period, further compounding the fall in assets.
Shares in the group closed down 5.3 per cent last night at 435p.