On 1 January 2016 the changes of the AbgÄG 2015 (BGBl I 163/2015) came into force and lead to a system change concerning the question of exit taxation. The biggest change occurred with the almost entire abolition of the non-imposition concept and its replacement with the new instalment-payment concept. But other changes, like the new rules concerning the absolute period of limitation for those cases, in which people chose the old non-imposition concept in the past, show the new understanding of the disclosure of hidden reserves. The main focus of this thesis lies on the field of cross-border contributions of businesses in accordance with Article 3 of the Austrian Reorganization Tax Act (UmgrStG) and the changes that came with the AbgÄG 2015 in this specific field. First of all, in order to understand the meaning of these changes, the author portrays the old legal situation, that was applicable until 31 December 2015. Subsequently the thesis presents the international aspects that play a crucial role in this complex matter. This concerns the rules of the OECD-MA, the requirements of European law and, most importantly, the influential jurisdiction of the ECJ that will be portrayed in more detail. Following this, the thesis concentrates on the new instalment-payment concept, its development and background. Here the main focus lies again on the special rules of the UmgrStG and the special problems connected with cross-border contributions of businesses. Then the thesis deals with possible effects of these changes and constitutional concerns that came up with them. For this, the thesis uses critical statements, which were made during the formation process of this law. It especially examines the constitutionality of the new rule in § 209 (5) of the Austrian Federal Fiscal Code (BAO), that has retroactive effect. Finally the author tries to draw a conclusion of the changes and tries to evaluate them from different perspectives.