Leonid Mikhelson, the head of Russia's largest independent gas producer Novatek, negotiated a deal to buy a 25% stake in Sibur Holding petrochemical company from Gazprombank. He and Novatek shareholder, and co-founder of energy trader Gunvor International, Gennady Timchenko, also agreed to take a two-year option to buy 9.4% of Novatek from Gazprombank. Together the pair already own more than 50% in the natural gas producer. In 1987, Mikhelson inherited management of expansive Soviet enterprise that built pipelines, roads and industrial facilities. Four years later he reorganized the company and began gathering up oil and gas production licenses, even accepting them as payment for construction work in order to build Novatek. In 2006 Gazprom bought nearly 20% of Novatek from Mikhelson and his partners, a deal widely seen as a way for the firm to ensure its survival. At that time, Mikhelson got $1 billion for part of his stake and was able to remain chairman. He is also a prolific art collector.