State-run Rosneft said on Monday it had acquired Yukos’s Moscow headquarters and other assets for an undisclosed amount from Prana, a mystery company, ending a bizarre coda in the bankruptcy of Mikhail Khodorkovsky’s oil group.

The state-controlled oil major announced on Monday it had completed the purchase of the Moscow office building and other assets, including trading company Yukos-M, which it said held “significant turnover capital”, reserves, and contractual rights. However, it declined to say how much it had paid Prana, pending publication of its financial results. Prana’s ownership remains unknown.