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International Tax Law: Globalization and Digitalization

Vak
2025-2026

Admission requirements

Students are recommended to have completed at least one year of university education (not necessarily in law or economics). We expect the students to have a good proficiency in English both orally and in writing.

Description

Context
In a globalizing and digitalizing economy, countries must collaborate to tax individuals and businesses effectively and fairly within their jurisdictions. International tax law governs this cooperation and is therefore an indispensable part of any well-functioning tax system today. For businesses, globalization has simplified cross-border operations, while digitalization has enabled companies to operate without a physical presence. Because current tax rules rely on physical presence to assign taxation rights to a single country, international organizations such as the OECD, and political forums like the G20, are exploring methods to tax profits generated by highly digitalized businesses and to ensure that each jurisdiction collects and enforces its “fair share” of taxes. For tax administrations, digitalization offers an opportunity to enhance the efficiency, effectiveness, and fairness of tax processes. However, administrations must also be mindful of the challenges posed by new digital technologies, as well as the limitations imposed by their administrative resources, personnel, and finances when implementing changes.

Place within the minor ‘(Inter)national tax planning and policy’
This course is part of the foundational track of the minor ‘(Inter)national tax planning and policy’. The minor investigates the nature and impact of tax planning activities by individuals and companies as well as the policy responses by governments, both in domestic law and through international cooperation. This course introduces students to essentials of international tax law and the main challenges that developed and developing countries face as they respond to the challenges posed by globalization and digitalization, such as the use of digital (online) platforms, the challenges in the use of new technologies and the rise of artificial intelligence.

Design of the course
During this course we study how new phenomena resulting from globalization and digitalization pose challenges and opportunities for contemporary tax systems. This course starts with a general introduction to the foundations of international tax law. Subsequently we will address the current challenges of international taxation considering the differences between developing and developed countries. For this purpose, we will use three cases studies: aggressive tax planning, mainly treaty shopping, taxation of highly digitalized business and the introduction of a minimum tax. In these case studies, we will address the different proposals made by international organizations, regional tax organizations, think tanks and civil society, countries and academics on how to address these issues. Finally, we will address the challenges that tax administration face in light of the three case studies mentioned above taking into account the differences between developed vs. developing countries.

It is important to understand how various stakeholders—including governments and companies from both developed and developing countries—interact. This course will equip students with the tools needed to navigate digital innovation challenges and prepare them for future roles as policy advisors in governments, NGOs, international organizations (such as the OECD and World Bank), supranational organizations (like the European Union), and regional organizations (including the ADB, ATAF, and African Union).

Course objectives

Upon completion of this course, students will:

  • have a basic understanding of why and how countries tax business operating across borders without a physical presence, and how business operate in a digitalized world.

  • have a basic understanding of the challenges of tax administrations in developed and developing countries to use innovative (digital) tools to ensure the enforcement and collection of taxes.

  • have a basic understanding of the initiatives developed by international organizations to deal with aggressive tax planning (e.g. Base Erosion Profit Shifting (BEPS) Project, Taxation of Highly Digitalized Business (Pillar 1) and Introduction of a Global Minimum Tax Rate (Pillar 2).

Timetable

Zie MyTimetable.

Mode of instruction

Lectures

  • Number of (2 hour) lectures: 4

  • Names of lecturers: Prof.dr. Irma Mosquera Valderrama and Prof. dr. Henk Vording

  • Required preparation by students: required Reading (see course overview in Brightspace)

Seminars

  • Number of (2 hour) seminars: 3

  • Names of lecturers: Prof.dr. Irma Mosquera Valderrama and Prof.dr. Henk Vording

  • Required preparation by students: assignments, required Reading (see course overview in Brightspace)

Assessment method

Examination form(s)

  • Written assignment (30%);

  • Final written exam (70%).

The grade for this course is based on one written assignment and a final, written examination at the end of the course. Depending on the number of students, we may choose to make the exam an oral exam instead of a written exam.

A passing grade for the course is 5.5 or higher. The assignment will count towards 30% of the final grade and the written exam will count towards 70% of the final grade. The assignment will be made in groups of 2 students. The students will be asked to discuss and present the assignment during the seminars.

Re-examination
Students who fail to obtain a passing grade for the course are entitled to a re-examination. The re-examination consists of an individual oral exam that will count towards 100% of the final grade.

Areas to be tested within the exam
The examination syllabus consists of the required reading (literature) for the course, the course information guide and the subjects taught in the lectures, the seminars and all other instructions which are part of the course.

Reading list

Obligatory course materials

  • Mosquera Valderrama I.J. & Heitmüller F. (2019), Corporate Tax, Digitalization and Globalization. WEF – Platform for Shaping the Future of Trade and Global Economic Interdependence: white paper. Cologny / Geneva: World Economic Forum.

  • Mosquera Valderrama I.J. (2023), Trade digitalization and taxation. In: Chaisse J. & Rodríguez-Chiffelle C. (red.), The Elgar Companion to the World Trade Organization. Elgar Companions to International Organisations series. Cheltenham: Edward Elgar Publishing. 90-107.

  • Christians A. & Apeldoorn L.C.J. van (2018), Taxing Income Where Value Is Created, Florida Tax Review 22(1): 1-39.

  • Gelepithis, M., & Hearson, M. (2022). The politics of taxing multinational firms in a digital age. Journal of European Public Policy, 29(5), 708–727. [Link]

  • Joshua Aslett, Stuart Hamilton, Ignacio Gonzalez, David Hadwick, and Michael A Hardy. "Understanding Artificial Intelligence in Tax and Customs Administration", Technical Notes and Manuals 2024, 006 (2024), accessed January 28, 2025, https://doi.org/10.5089/9798400290435.005

Additional materials will made available on Brightspace.

Registration

Registration for courses and exams takes place via MyStudymap. If you do not have access to MyStudymap (guest students), look here (under the Law-tab) for more information on the registration procedure in your situation.

Contact

Institution/division

  • Institute: Department of Tax Law and Economics

  • Department: Tax Law

  • Room number secretary: B2.11

  • Opening hours: Mon-Fri 9.00-17.00

  • Telephone number secretary: 071 – 527 7840

  • Email: belastingrecht@law.leidenuniv.nl

Remarks