A judge has ordered Oleg Deripaska and his associates to pay up to 70% of Quinn Emanuel Urquhart & Sullivan's costs for resisting a crucial disclosure application, in an ongoing legal wrangle with the Russian oligarch.

Earlier this month, the law firm was ordered by London's High Court to reveal the identity of the supplier of an allegedly forged document that claimed Deripaska had underpaid a rival by roughly $300 million in a buyout deal.