The investment company of two of Russia’s richest men has said it will not sell its stake in one of the country’s largest mobile operators, despite being hit with a $1.5bn (€1.2bn) margin call on a loan from Deutsche Bank.

According to research from Unicredit, Altimo, which is controlled by billionaire businessmen Mikhail Friedman and Petr Aven, is in the process of renegotiating a $1.5bn loan from Deutsche Bank. This follows falls in the shares of mobile operator Vimpelcom, which were pledged as collateral against the borrowing, triggered a margin call.