 Access currently owns approximately 14% of LyondellBasell.AAR gained a controlling stake in Russian oil company TNK through privatization auctions, then in 2003 sold a 50% stake to British Petroleum to form TNK-BP, one of Russia's largest oil companies, where Blavatnik served on the board of directors.On March 21, 2013, Rosneft completed its $55 billion acquisition of TNK-BP.