The concept of service of general economic interest (SGEI) is an evolving notion that depends, among other things, on the needs of citizens, technological and market developments and social and political preferences in the Member State concerned. It transpires from Article 106(2) of the Treaty that undertakings entrusted with the operation of SGEIs are undertakings entrusted with ‘a particular task’. Generally speaking, the entrustment of a ‘particular public service task’ implies the supply of services which, if it were considering its own commercial interest, an undertaking would not assume or would not assume to the same extent or under the same conditions . Based on Article 107(1) of the Treaty, the State aid rules generally only apply where the recipient is an ‘undertaking’. Whether or not the provider of a service of general interest is to be regarded as an undertaking is therefore fundamental for the application of the State aid rules.