KIEV, May 20 – RosUkrEnergo, a Swiss-based gas trader co-owned by Ukrainian billionaire Dmytro Firtash, will seek to win $5.4 billion in compensation from Naftogaz Ukrayiny for “illegal” confiscation of its gas in 2009.

RosUkrEnergo will seek the cash compensation, rejecting a recent of offer from Naftogaz to settle the case by returning 11 billion cubic meters of natural gas.