Risks related to the supply security of natural gas within the European Union gained in particular in importance in the context of the recent market liberalization. Prior to market opening the issue of security of supply has been principally covered by the monopolistic or state-controlled player. Recently, this turned into a more complex issue as private companies under competition have to recover their costs for security from the customer in an increased volatile market. While the EU's national champions try evolving their business upstream, multinational integrated oil and gas producers as well as state-controlled companies of producers' states arrive now in the liberalized European market in order to vertical integrate their supply chain. However, their political power adds a significant risk of market distortion to the freshly opened European market.