On Thursday 1 December 2016 at 13.45 hrs, Francisco Sepulveda Ramirez will defend his doctoral thesis ‘Residence in Tax Treaties' at the Academy Building of Leiden University. Supervisor is Professor F.A. Engelen.

On Thursday 16 November, Dirk Broekhuijsen defended his doctoral thesis entitled ‘A multilateral tax treaty: designing an instrument to modernise international tax law’. The supervisors are Professor F.A. Engelen and Professor S.C.W. Douma.

Multinationals use loopholes in the tax treaties between different states. A possible solution would be to eliminate all these loopholes in one go by creating a central global treaty. Leiden researchers are investigating whether this kind of mega-treaty is feasible.

On 10 October 2018, Richard Resch defended his doctoral thesis 'The Interpretation of Plurilingual Tax Treaties'. The doctoral research was supervised by Prof. mr. C. van Raad.

On Thursday 1 December 2016 at 13.45 hrs, Francisco Sepulveda Ramirez will defend his doctoral thesis ‘Residence in Tax Treaties' at the Academy Building of Leiden University. Supervisor is Professor F.A. Engelen.

On Thursday 16 November, Dirk Broekhuijsen will defend his doctoral thesis entitled ‘A multilateral tax treaty: designing an instrument to modernise international tax law’. The defence will take place at 15.00 hrs at the Academy Building of Leiden University. The supervisors are Professor F.A. Engelen…

Minister Silvania of Curaçao has announced that Germaine Rekwest, who was awarded a PhD from Leiden University in September, will support him on treaty policy for Curaçao. The minister announced this in his travel report.

PhD candidate Manon Wintgens is using an algorithm to trawl through thousands of international tax treaties. She hopes to detect a system in the dizzying interplay between countries, businesses and documents. It is a unique research project.

Loopholes in international tax legislation contribute to the misuse of tax rules by multinationals. Leiden University legal experts investigate how the complex national and international tax rules can be made more consistent in order to create a better tax system.

In the past few years, an increasing number of multinationals have made the news for large-scale use of tax planning opportunities. The Organisation for Economic Collaboration and Development (OECD) and the European Commission are studying these cases closely and investigating whether the current concepts…

How do tax treaties have to be explained and implemented, and what role does the supranational regulatory process play in this? Which objectives are meant to be used in establishing tax regulations and to what extent are such legislative practices undertaken in a goal-oriented manner?.

Complex systems can be characterized as systems in which multiple components interact with each other, often in non-linear ways. The main goal of this research will be to investigate if and how the international tax system can be defined and modelled as a complex system. Approaching the international…

The study of tax law covers the tax system in its full width. It includes domestic, international and European tax law.

On 13 January 2022, Pie Habimana defended the thesis 'Harmful Tax Competition in the East African Community'. The doctoral research was supervised by Prof. H. Vording and Prof. S.C.W. Douma (UvA).

In this PhD-thesis several new and existing data science application are described that are particularly focused on applications for tax administrations.

Tax scandals, like the Panama Papers, the Paradise Papers, and the Pandora Papers, have made taxation a major topic of public debate. Learn more about this in the new minor Tax and Society: Building a Sustainable and Fair Tax System.

PhD defence

The master’s programme 'Fiscaal Recht' provides you with in-depth theoretical and practical knowledge on all the ins and outs of tax law.

The EUTAXGOV Chair will address the EU Standard of Tax Good Governance. This Standard has been introduced in 2008 by the ECOFIN Council with a view to tackle tax fraud and evasion by companies and individuals and as a pre-condition for third (non-EU) countries that receive EU development aid, and concluded…

Do you like solving complex legal puzzles? Do you like analysing problems? If so, the bachelor’s programme Fiscaal Recht is right for you.

Courses EU Tax Governance (EUTAXGOV).

Before he became Minister of Finance, CDA leader Wopke Hoekstra invested for years in a shell company in the Virgin Islands. This has been revealed in leaked documents known as the Pandora Papers. How exactly does tax avoidance work? And are there other options? Tax lawyers Jan Vleggeert and Tanja…

The following lectures/courses are given in the framework of the EU Jean Monnet Chair EUTAXGOV at Leiden University. Topic of this Jean Monnet Chair: EU Tax Governance and International Tax Law Making by the EU.

The Institute of Tax Law and Economics at Leiden Law School has three departments: the Department of Tax Law, the Department of Economics and the Department of Business Studies. The Institute brings together research and teaching at the point at which, on the one hand, law and, on the other, fiscal…

The Panama Papers and Paradise Papers provide evidence that companies and individuals are evading tax on a large scale. Worldwide tax agreements can put a stop to this. But for the time being a treaty that will address the problem at its root is not in sight, in the opinion of legal expert Dirk Broekhuijsen.…

Joris Larik, Assistant Professor at Leiden University, wrote about the topics of the Brexit, the EU-UK Withdrawal Agreement, and Global Treaty (Re-)Negotiations.

William Lippert investigates the effect of delegation to an agreement executor on success of conventional arms control agreements in Europe.

That the tax authorities are allowed to impose taxes is widely known. What is less well known is when the tax authorities must impose taxes. And what to do when one set of regulations requires the tax authorities to impose taxes while other regulations prevent them from doing exactly that? Vergouwen’s…

The Dutch Tax Authorities leaked information about an international tax audit to Uber. In addition, they ‘obstructed and delayed’ an investigation by other EU Member States, says the International Consortium of Investigative Journalists (ICIJ) based on internal documents from the tech company.

The Data Science Research Programme at Leiden University combines data science with PhD projects in a wide range of disciplines. The programme has been running for over two years, and is producing the first astonishing results. A number of PhD candidates talk about their experiences and research bel…

Assessing the feasibility and legitimacy of the current model of global tax governance and the role of the OECD and EU in international tax law-making.

Dutch newspaper Trouw investigated the tax position of multinational Cargill. Their conclusion? Cargill appears not to pay taxes over their profits. Trouw asked Jan van de Streek, Professor of Tax Law, and PhD candidate Josephine van der Have for an explanation. Prior to this, Van der Have had also…

On 19 December 2019, Reza Eftekhar defended his thesis 'The Role of the Domestic Law of the Host State in Determining the ratione materiae Jurisdiction of Investment Treaty Tribunals: The Partial Revival of the Localisation Theory'. The doctoral research was supervised by Prof. E. de Brabandere.