Yuganskneftegaz was the core production subsidiary of Yukos Oil Company, which was previously run by Russian businessman Mikhail Khodorkovsky. In 2003, the Russian tax authorities charged Yukos and Khodorkovsky with large-scale tax evasion. On April 14, 2004, Yukos was presented with a bill for over US $35 bn in back taxes and a demand to pay the entire bill the same day. Requests by Yukos to defer payment, allow payment by instalments or to discharge the debt by sale of peripheral assets, including its shareholding in the Sibneft oil company, were also refused. Since Yukos was both legally and physically unable to pay the entire amount in cash on such short notice, Russian bailiffs froze Yukos’ shares in Yuganskneftegaz.