International and cross-border transactions, such as share deals with subsequent reorganizations, are becoming increasingly important in business practice. In addition to the corporate law requirements for reorganizations, which can be found, among other acts, in the EU Reorganization Act (EU-UmgrG), the tax consequences set out in the Reorganization Tax Act (UmgrStG) must also be taken into account. The introduction of the Pillar II regulations (in Austria in the form of the Minimum Taxation Act [MinBestG]) has added to the complexity and sensitivity of the issue. The aim of this article is to provide an initial overview of the provisions of the Minimum Tax Act and Austrian tax law that must be observed in this context when an Austrian target is acquired by a multinational group of companies, followed by a cross-border upstream merger. Therefore, in the case of a planned share deal, we recommend examining corporate, tax, and Pillar II aspects as part of a due diligence in the future.