Since its implementation in 2005 the Austrian group taxation regime has already undergone several major changes. The most recent one has occurred in the course of the revision of the Austrian Tax Act 2014 (Abgabenänderungsgesetz 2014). One of the new regulations which were introduced caused a particular heated debate; from January 1st 2015 only nonresident group members that are located in the European Union or in third-party countries that share comprehensive administrative assistance (umfassende Amtshilfe) with Austria can be included into tax groups. The moving cause for the limitation of the Austrian group taxation regime was a report by the board of audit published in 2013 that expressed severe criticism towards the actual system as there was a lack of control over the group members situated in countries without comprehensive administrative assistance. One of the findings of the research demonstrates that international cooperation in the field of taxation is inevitable to avoid tax avoidance and evasion on the one hand and double taxation of crossborder issues on the other. The challenge regarding international cooperation is the multitude of sources that range from several bi- and multilateral agreements to national regulations such as the Administrative Assistance Implementation Act. Despite the high number of sources of law the term "comprehensive assistance" is neither mentioned nor defined which lead to great uncertainty as the changes in the group taxation regime were announced. To end the debate which countries do or do not fulfill the criteria for comprehensive assistance the Federal Ministry of Finance published an information that listed all the countries that were eligible to be part of the Austrian group taxation system. The impact of the changes on the group taxation are farreaching, as they significantly limit both the geographical scope and the possibility of the inclusion of losses itself. Due to the inconsistency and incompleteness of the data provided in the report of the board of audit, the amount of foreign group members that are affected by the changes cannot be estimated accurately. On the basis of the available data 2% up to 30% of the existing taxation groups in Austria could be concerned by the restrictions. A final statement on the impact of changes can therefore only be made when the necessary data is collected and published by the Federal Ministry of Finance.