(Slavneft being a very large Russian Oil company owned 50/50 by Gazprom and TNK-BP)

from Wikpedia

Viktor Felixovich Vekselberg (Russian: Виктор Феликсович Вексельберг, Ukrainian: Віктор Феліксович Вексельберг; born April 14, 1957, Drohobych, Ukraine, Soviet Union) is the owner and president of Renova Group, a large Russian conglomerate.

After working as an engineer in an obscure state lab for many years, Vekselberg moved to business in 1990. He rose to prominence after Yeltsin's reelection in 1996 as co-owner and chairman of Tyumen Oil (TNK), one of Russia's largest oil and gas companies. He took a controlling interest in the company in 1997 and has subsequently developed a joint venture with BP. About the same time he co-founded SUAL Holding, which since grew to control Russia's second-largest aluminum business and is ranked ninth in the world. Later, he integrated those and other assets under the umbrella of Renova Group, delegating operating responsibilities to managers. Acting as a chairman of the executive board of TNK, he was instrumental in negotiating and establishing a 50-50 joint venture with British Petroleum in the largest private transaction in Russian history. He is currently a member of the board of directors and the vice-president of TNK-BP.

From TNK-BP website:

Viktor F. Vekselberg

Executive Director for Gas Business Development

From another article: Mr Vekselberg, whose Renova Group owns 12.5 per cent of TNK-BP,