BP signalled the end of its nine-year joint venture in Russia today after confirming it would pursue the sale of the 50% shareholding.
TNK-BP, which is among the top ten privately-owned oil companies in the world, was built from the merger of BP's Russian oil and gas assets and those of four tycoons in the Alfa, Access/Renova group (AAR).
BP has notified AAR of its intention to sell its stake after receiving "unsolicited indications of interest" regarding the shareholding.
It comes in the week that one of the AAR billionaires, Mikhail Fridman, said the 50-50 ownership structure no longer served the interests of each party.
Having announced his resignation as chief executive on Monday, Mr Fridman told Russian newspaper Kommersant: "Everything is possible and realistic. We are open to proposals. There are a lot of different options."
BP and Russian oil company Rosneft last year offered to buy out AAR for about £20 billion as part of an attempt to salvage their Arctic exploration tie-up, which AAR had blocked.
TNK-BP has exploration and production assets as well as downstream marketing operations in Russia and Ukraine, alongside interests in Brazil, Venezuela and Vietnam.