However, the government, facing a debt-repayment hump next year, wants to raise as much from the Slavneft sale as possible.

ECONOMIST: Russia's oil auction

Already, Sibneft, with Tyumen, controls nearly a quarter of Slavneft.

ECONOMIST: Russia's oil auction

Born in Kazakhstan, where his Ingush family had been deported after World War II, Gutseriev became the president of state oil company Slavneft, but was dismissed in 2002 before privatization.

FORBES: Mikhail Gutseriev

Last month, when the Belarussian government realised what was happening and tried, belatedly, to sell its own 10.83% stake in Slavneft before the Russian auction devalued it, Sibneft was the only bidder.

ECONOMIST: Russia's oil auction