Russian gas major Gazprom is arranging $10 billion in financing to facilitate its takeover of Sibneft, according to bankers working on the deal. If completed, the sums involved would make the buyout the largest in Russian history.

State controlled Gazprom’s takeover target Sibneft is 72% owned by the oligarch Roman Abramovich and his partners.

The buy out plan for Sibneft comes at a time when Russian premier Vladimir Putin has been engaging in regaining tighter regulatory control on Russia’s energy sector. In addition to Gazprom’s interest in Sibneft, recent developments have included a Russian government crackdown on unpaid taxes and state owned Rosneft’s purchase of Yuganskneftegaz from bankrupt oil firm Yukos.

If successful in its endeavor, Gazprom, the world’s largest natural gas producer, would add an output of 693,000 barrels of oil a day from Sibneft, Russia’s fifth-largest oil producer, to its portfolio.

Gazprom is currently negotiating the major financing with ABN Amro and Dresdner Kleinwort Wasserstein with a view to completing an acquisition deal by the fall. Including the record financing, the final purchase price could be in the region of $14 billion, in line with estimates made last month by the Vedemosti newspaper.