Naftogaz Ukrainy and its six subsidiaries on October 17, 2016 initiated arbitration proceedings against the Russian Federation with the requirement to reimburse for losses caused by the illegal seizure of the group's assets in Crimea. Naftogaz preliminarily estimated the damage to the group at $2.6 billions.In Crimea Naftogaz had several valuable energy assets, the seizure of which by the Russian side violates the bilateral investment agreement, which requires the Russian Federation to respect and protect Ukrainian assets, including those located in Crimea.