The injection of unprecedented amount of public resources into the banking sector has represented a relevant trial for the state aid regime during the financial crisis. The paper deals with the Commission's policy reaction to the crisis and the question of whether this action has produced changes in the notion of state aid. In particular it describes the Commission's role in the management and resolution of the crisis in the banking sector. Moreover it explores the features of the action aimed at combining the objective of restoring financial stability in the short-term with that of ensuring effective competition in the medium-term. Over the crisis the interventions of the European Commission have been characterized by a high degree of flexibility concerning 1) the compatibility analysis of aid measures for banks 2) procedures 3) criteria for assessment (see market economy investor principle). All in all the paper highlights the notion of state aid and its use comparing «standard/general rules» and «emergency rules» in the assessment procedure of its compatibility and challenges the concept of state aid and its traditional all-inclusive meaning.