As Mikhail Khodorkovsky, the former owner of oil company Yukos, is to start his eight-year prison sentence for fraud and tax evasion, his former business partner and owner of Chelsea Football Club, Roman Abramovich is poised to receive US$13bn for 72% in Sibneft oil company, which he sold to Gazprom, the gas monopoly.

Yukos and Sibneft were created and privatised at knock-down prices ahead of the 1996 presidential election. A group of Russian oligarchs received shares in companies in exchange for loans made to the Kremlin.

Both companies were run aggressively by their owners who minimised tax payments to below the statutory rate of 24% in 2001. Over the past two years Yukos has been crippled by US$28bn in tax claims and the largest part of the company forcibly sold in an auction to Rosneft, a state-owned oil company. Sibneft on the other hand, was yesterday acquired by Gazprom.

The seller is Millhouse Capital, a London-based investment company controlled by Abramovich, Russia’s richest man who is believed to be close to the Kremlin. The full shareholder structure of Millhouse Capital has never been publicly disclosed and all it would say was that Abramovich and his partners controlled it.

Al Breach, chief strategist at UBS Brunswick, says the sale of Sibneft marks the end of one of the most controversial privatisation deals in Russian history. “The original sin was the shares-for-loans privatisation in 1995. The sale of Sibneft is bringing that chapter to an end. Gazprom has paid the market price for the company, and that is good news for the market.”

Abramovich is one of the first Russian oligarchs to exit a company bought under the programme. However, he could still face legal action from former partners. Boris Berezovsky, once a co-owner of Sibneft told the FT he would next month file a legal case against Abramovich in a London court for allegedly pressuring him to sell his stake of the company at a knock-down price on the Kremlin’s order.

Abramovich and Millhouse Capital also face action from Sibir Energy, listed on London’s Aim market, which alleges that Sibneft stole 50% of Sibneft-Yugra, a joint venture to develop the South Proiobskoe field in western Siberia. It alleges Sibneft diluted its 50% stake to 1% through a share issue Sibir was not told about. The case has been filed in the British Virgin Islands.

It is not the first time that Abramovich has tried to sell his company. Sibneft has twice tried to merge with Yukos, most recently in 2003.

As part of the merger deal to create Russia’s largest oil company, Abramovich received US$3bn in cash in addition to Yukos’s shares. But a few months later Khodorkovsky was arrested and the government attacked Yukos. Abramovich called off the merger and unwound the share swap. The US$3bn was never paid back and Yukos still owns 20% of Sibneft.

After the dismantling of Yukos the Kremlin was no longer prepared to sell majority stakes in Russian oil companies to foreign buyers. This meant that the only possible buyer for Sibneft would be a state-controlled entity such as Gazprom.

Gazprom argues the deal is part of its strategy to become a global integrated energy player. But Steven O’Sullivan, head of research at UFG, an investment bank, is not convinced. “It is not unusual for oil companies to go into gas, but we have not seen many gas companies buying oil assets.”

Yuri Trutnev, Russia’s natural resources minister, told the FT: “This acquisition enhances the strength of Gazprom and makes it a powerful player in the global market.” On the other hand the creation of such a giant, Trutnev said, could put pressure on smaller players.