CEE states, following their accession into the European Union in 2004 and 2007, have been inundated with numerous lawsuits by foreign and, in many cases, European investors in front of international tribunals. Some of these cases involved state aid provided by member states to investors and when these state aid measures were revoked, based on decision of the European institutions, the aggrieved investors turned to both EU instances and international arbitrations. These EU decisions forced CEE states to take certain measures, often by curtailing contractual rights awarded by CEE states to international or Western European investors. The investors tried to invalidate the European Commissions’ decisions in front of the EU Court of First Instance/General Court and subsequently in the Court of Justice. When these initiatives failed, the facts of these cases were subsequently represented by many of these investors in international fora, such as the International Centre for Settlement Investment Disputes (ICSID), or arbitrations organised under the UNCITRAL rules.