Efforts to harmonize European corporate taxation have largely been fruitless so far. A particular issue is that a common corporate tax base cannot be linked to either national commercial law or IFRS when it comes to interpretation questions. Johannes Kuhr derives a foundational principle on which an independent tax profit determination in Europe can be based. He contrasts principles of European corporate taxation (GEUB), as they can be induced de lege lata from the corporate tax laws of the 28 member states, with those GEUB de lege ferenda, which can be deduced from a catalog of fundamental requirements for corporate taxation in Europe that he has established.