The event will be held in a hybrid format, both online and on face-to-face, the days 15 and 16 September 2025.
The symposium focuses on the challenges of the international tax system and the right and tax polity in the different jurisdiction of the contemporary world. The politics in charge, the enterprises and people are faces with a number of international and national challenges that go from the rapid digitalisation of the economy, climate change, the development of capacities in income mobilisation, to the formulation of international fair and equitable tax politics. The global endorsement of the Two Pillar Solution and the application of the Pilar II in a number of jurisdiction have been a new challenge for the tax administration and the compliance with tax obligations from governments and enterprises, and they have raised new issues about the fair assignation of the financial incomes between jurisdictions. Recent events, actions and reactions of the tax global governance make this encounter unique to debate the present tendencies in international, supranational and national tax legislation and policies. With this backdrop, this symposium has as goal explore ideas and approaches to face the challenges of international taxation and the national tax evolution.
The symposium takes research contributions both theoretical and empirical. The themes of interest include, within others, the institutional development of an international fair tax policy, inclusive and equitable; the implementation of Pilar II (or a global minimum tax) and the challenges for the legal systems and administrative at international and/or national level; the sustainability of the generation of fiscal incomes in the digital era; the taxation and environment; inequality and wealth taxation; global taxation governance; and the implications of the automation and artificial intelligence for the income and general consumption taxes.
The symposium offers a unique opportunity for the doctorates and junior researchers that contribute with innovative ideas and critique existent students about taxation, could benefit with the debated with experts of different disciplines and jurisdictions, and develop research networks and professionals for the development of their careers.
If you are interested in participating in the GTS doctorate symposium, send an abstract with no more than 300 words in Word or Adobe PDF format to tax@uv.es. The selected works will be presented in the symposium and will receive commentaries of a group of experts in the relevant theme.
The presentation deadline ends on 30 May 2025. The authors of the accepted lectures will be notified before 15 June 2025. To consult the past sessions of the symposium about global taxation of doctorates, look in this web.
Workshop Programme
Impact of Carbon Border Adjustment Mechanism (CBAM) and AI on Sustainable Development in Asia
Workshop 1-2 October
Online via zoom
On 1 and 2 October, the Asian Development Bank (ADB) together with Irma Mosquera Valderrama (GLOBTAXGOV Project at the Leiden Law School -Leiden University the Netherlands), Suranjali Tandon (National Institute of Public Finance and Policy, New Delhi, India), Marta Villar (DIGICCTAX G20/2-05 San Pablo CEU University, Spain) and Mahmoud Mahmoud Abdellatif (Qatar University) organize an online (via zoom) workshop on The impact of CBAM and AI on Sustainable Development in Asia.
Date and Time
Leiden, The Netherlands: First day (1 October ) from 10:00-13:00 p.m. and Second day (2 October) from 9:00-12:00 Time zone: Central European Summer Time CEST (Amsterdam, Berlin, Paris)
Manila, Philippines: First day (1 October ) from 16:00-19:00 p.m. and Second day (2 October) from 15:00-18:00 p.m.
Who should attend?
This workshop is addressed to academics, including junior and senior researchers, government officials, policy makers (EU, regional and international organizations), among others.
Link to registration here
Registration is free.
Venue
Online: Link via ZOOM: When registered, you will receive a link for the event upon registration.
Moderator
Irma Mosquera Valderrama, is Full Professor Tax Governance at Leiden Law School (Leiden University), the Netherlands. She is also the EU Jean Monnet Chair Holder on the topic EU Tax Governance (EUTAXGOV), and Lead Researcher of the European Research Council (ERC) Funded Project that investigates Global Tax Governance (GLOBTAXGOV).
Contact details: Email i.j.mosquera.valderrama@law.leidenuniv.nl
Background
Carbon border adjustment mechanism is a policy tool that the EU is using to ensure that trade with EU complies with its internal standards on emissions. That is, emissions embedded in imports are capped and priced implicitly equivalent to the EU. While in its first phase it applies to six sectors, over time the scope of the measure will expand. This is expected to have an impact on developing countries that export products such as iron and steel, cement, aluminum and fertilizers to the EU. Not all exporters have similar emissions standards and pricing mechanisms. While the measure is a step in the right direction, it is does not take into account different levels of development and pace of decarbonisation. CBAM will impose costs of compliance on exporters from developing countries and in many cases render them uncompetitive.
While CBAM applies to goods exports, there is an interlinkage between the technological advancements and carbon emissions. To run complex computational models would require more energy and this would mean that unless countries meet their energy requirements from renewables, the technological advancements including trade of bitcoins would lead to higher emissions. A more important point to consider is that data centers are located in United States (3736) and Europe (3017). Thus it is important to explore the spatial contribution to the emissions. Export of digital services also contributes to emissions and it is estimated that at the end of the decade 2.5 billion tonnes will be emitted by the data centers. A large contribution to this will be from the big tech companies. As per another estimate data centers currently contribute 2% of GHG emissions. Their contribution is therefore not insignificant. Thus even as EU plans to impose an emission standard for goods trade where CBAM certificates are priced equivalent to the emission trading system, such emissions that are generated from services also need thought as countries and regions plan digitalization.
This workshop wants to address these challenges with a focus on ADB Member Countries. The first day of the workshop will focus on the understanding of the CBAM, some ADB countries practices, and an assessment on whether the CBAM will be effective to cut carbon emissions. In order to do that, the first day will provide a multidisciplinary perspective from trade, economy, tax and investment.
The second day of the workshop will address the challenges of ADB countries in achieving a sustainable environmental policy in light of the AI development and the growing digital transformation in Asia. The main question addressed will be how to reduce carbon emissions from the use of data centers? What are the obstacles, challenges and opportunities for ADB countries. Finally this day will conclude with a proposal for a Sustainable Green AI adoption policy for all countries.
Several authors from Asian Development Bank Member countries in Asia and Europe have been invited to present their papers on topics such CBAM, AI, Environmental Sustainable Development, Regional Frameworks, among others. This workshop is also organized in the framework of the Strategic Partnership between Leiden University and ADB. More information on this partnership available here.
Navigating Global Tax Governance: A workshop with African Tax Administration Forum
Lecturers
Prof. Dr. Irma Mosquera
Professor of Global Tax Governance, Lead Researcher GLOBTAXGOV that investigates Global Tax Governance and EU Jean Monnet Chair Holder EUTAXGOV E-mail i.j.mosquera.valderrama@law.leidenuniv.nl
Guest lecturers
Prof. Jérôme Monsenego Stockholm University
Dr. Bastiaan van Gaanzen Leiden University
Mr. Tofigh Hasen Nezhad Nisi Leiden University (t.b.c.)
ATAF representatives (t.b.a.)
Dates
14 November 2025, 13:00 UTC – 16:00 UTC
21 November 2025, 13:00 UTC – 16:00 UTC
28 November 2025, 13:00 UTC – 16:00 UTC
5 December 2025, 13:00 UTC – 16:00 UTC
Venue
Online
Summary
Since the 2008 financial crisis, multilateral cooperation in international tax law has developed at a fast pace. Currently, OECD and non-OECD countries have agreed to introduce international tax policy standards to tackle aggressive tax planning, to introduce a global minimum tax and to tax digital business among others. For individual countries, multilateral cooperation can result in economic benefits, but navigating the global governance architecture also bears many challenges. How to effectively engage in global governance processes? How to evaluate the outcomes?
In this workshop we will discuss the content of international tax standards and analyze the policy objectives and strategies pursued by different international, supranational and regional organizations, such as the United Nations, the OECD, the EU, among others, in the process. We will also pay attention to the challenges to the current structure of global governance due to the interactions between policy norms and legal instruments in the tax, trade and investment area.
In the first part, we will address how the global tax governance architecture has emerged and map the contemporary environment of international actors. Thereafter, we will discuss governance processes and actors involved in three case studies of specific policy areas: the role of the EU in the dissemination of BEPS standards, the taxation of the digital economy, and the introduction of a global minimum tax. In each case study, we will pay particular attention to the engagement of non-OECD countries with international institutions and the interaction between tax, trade and investment policy objectives and rules. In the final part of the workshop, we will discuss global tax governance under the lens of legitimacy and attempt to draw broader conclusions about the role of different actors in multilateral cooperation. Special attention will be given to the ongoing negotiation of the UN Framework Tax Convention and its two Protocols under the lens of legitimacy.
Procedure
Every session consists of lecture elements, input from ATAF, and general debates among all participants. In the lecture elements, the theoretical foundations will be exposed by Leiden University researchers. In the applied part, guest lecturers from ATAF discuss the topic based on examples from the region and based on ATAF’s experience in engaging in global tax governance. For the general debate, all participants are expected to actively participate and share their own experiences with the topic. To prepare for each session, all participants are requested to read the literature and complete the assignments.
Navigating Global Tax Governance: A workshop with African Tax Administration Forum
Lecturers
Prof. Dr. Irma Mosquera
Professor of Global Tax Governance, Lead Researcher GLOBTAXGOV that investigates Global Tax Governance and EU Jean Monnet Chair Holder EUTAXGOV E-mail i.j.mosquera.valderrama@law.leidenuniv.nl
Guest lecturers
Prof. Jérôme Monsenego Stockholm University
Dr. Bastiaan van Gaanzen Leiden University
Mr. Tofigh Hasen Nezhad Nisi Leiden University (t.b.c.)
ATAF representatives (t.b.a.)
Dates
14 November 2025, 13:00 UTC – 16:00 UTC
21 November 2025, 13:00 UTC – 16:00 UTC
28 November 2025, 13:00 UTC – 16:00 UTC
5 December 2025, 13:00 UTC – 16:00 UTC
Venue
Online
Summary
Since the 2008 financial crisis, multilateral cooperation in international tax law has developed at a fast pace. Currently, OECD and non-OECD countries have agreed to introduce international tax policy standards to tackle aggressive tax planning, to introduce a global minimum tax and to tax digital business among others. For individual countries, multilateral cooperation can result in economic benefits, but navigating the global governance architecture also bears many challenges. How to effectively engage in global governance processes? How to evaluate the outcomes?
In this workshop we will discuss the content of international tax standards and analyze the policy objectives and strategies pursued by different international, supranational and regional organizations, such as the United Nations, the OECD, the EU, among others, in the process. We will also pay attention to the challenges to the current structure of global governance due to the interactions between policy norms and legal instruments in the tax, trade and investment area.
In the first part, we will address how the global tax governance architecture has emerged and map the contemporary environment of international actors. Thereafter, we will discuss governance processes and actors involved in three case studies of specific policy areas: the role of the EU in the dissemination of BEPS standards, the taxation of the digital economy, and the introduction of a global minimum tax. In each case study, we will pay particular attention to the engagement of non-OECD countries with international institutions and the interaction between tax, trade and investment policy objectives and rules. In the final part of the workshop, we will discuss global tax governance under the lens of legitimacy and attempt to draw broader conclusions about the role of different actors in multilateral cooperation. Special attention will be given to the ongoing negotiation of the UN Framework Tax Convention and its two Protocols under the lens of legitimacy.
Procedure
Every session consists of lecture elements, input from ATAF, and general debates among all participants. In the lecture elements, the theoretical foundations will be exposed by Leiden University researchers. In the applied part, guest lecturers from ATAF discuss the topic based on examples from the region and based on ATAF’s experience in engaging in global tax governance. For the general debate, all participants are expected to actively participate and share their own experiences with the topic. To prepare for each session, all participants are requested to read the literature and complete the assignments.
Navigating Global Tax Governance: A workshop with African Tax Administration Forum
Lecturers
Prof. Dr. Irma Mosquera
Professor of Global Tax Governance, Lead Researcher GLOBTAXGOV that investigates Global Tax Governance and EU Jean Monnet Chair Holder EUTAXGOV E-mail i.j.mosquera.valderrama@law.leidenuniv.nl
Guest lecturers
Prof. Jérôme Monsenego Stockholm University
Dr. Bastiaan van Gaanzen Leiden University
Mr. Tofigh Hasen Nezhad Nisi Leiden University (t.b.c.)
ATAF representatives (t.b.a.)
Dates
14 November 2025, 13:00 UTC – 16:00 UTC
21 November 2025, 13:00 UTC – 16:00 UTC
28 November 2025, 13:00 UTC – 16:00 UTC
5 December 2025, 13:00 UTC – 16:00 UTC
Venue
Online
Summary
Since the 2008 financial crisis, multilateral cooperation in international tax law has developed at a fast pace. Currently, OECD and non-OECD countries have agreed to introduce international tax policy standards to tackle aggressive tax planning, to introduce a global minimum tax and to tax digital business among others. For individual countries, multilateral cooperation can result in economic benefits, but navigating the global governance architecture also bears many challenges. How to effectively engage in global governance processes? How to evaluate the outcomes?
In this workshop we will discuss the content of international tax standards and analyze the policy objectives and strategies pursued by different international, supranational and regional organizations, such as the United Nations, the OECD, the EU, among others, in the process. We will also pay attention to the challenges to the current structure of global governance due to the interactions between policy norms and legal instruments in the tax, trade and investment area.
In the first part, we will address how the global tax governance architecture has emerged and map the contemporary environment of international actors. Thereafter, we will discuss governance processes and actors involved in three case studies of specific policy areas: the role of the EU in the dissemination of BEPS standards, the taxation of the digital economy, and the introduction of a global minimum tax. In each case study, we will pay particular attention to the engagement of non-OECD countries with international institutions and the interaction between tax, trade and investment policy objectives and rules. In the final part of the workshop, we will discuss global tax governance under the lens of legitimacy and attempt to draw broader conclusions about the role of different actors in multilateral cooperation. Special attention will be given to the ongoing negotiation of the UN Framework Tax Convention and its two Protocols under the lens of legitimacy.
Procedure
Every session consists of lecture elements, input from ATAF, and general debates among all participants. In the lecture elements, the theoretical foundations will be exposed by Leiden University researchers. In the applied part, guest lecturers from ATAF discuss the topic based on examples from the region and based on ATAF’s experience in engaging in global tax governance. For the general debate, all participants are expected to actively participate and share their own experiences with the topic. To prepare for each session, all participants are requested to read the literature and complete the assignments.
Navigating Global Tax Governance: A workshop with African Tax Administration Forum
Lecturers
Prof. Dr. Irma Mosquera
Professor of Global Tax Governance, Lead Researcher GLOBTAXGOV that investigates Global Tax Governance and EU Jean Monnet Chair Holder EUTAXGOV E-mail i.j.mosquera.valderrama@law.leidenuniv.nl
Guest lecturers
Prof. Jérôme Monsenego Stockholm University
Dr. Bastiaan van Gaanzen Leiden University
Mr. Tofigh Hasen Nezhad Nisi Leiden University (t.b.c.)
ATAF representatives (t.b.a.)
Dates
14 November 2025, 13:00 UTC – 16:00 UTC
21 November 2025, 13:00 UTC – 16:00 UTC
28 November 2025, 13:00 UTC – 16:00 UTC
5 December 2025, 13:00 UTC – 16:00 UTC
Venue
Online
Summary
Since the 2008 financial crisis, multilateral cooperation in international tax law has developed at a fast pace. Currently, OECD and non-OECD countries have agreed to introduce international tax policy standards to tackle aggressive tax planning, to introduce a global minimum tax and to tax digital business among others. For individual countries, multilateral cooperation can result in economic benefits, but navigating the global governance architecture also bears many challenges. How to effectively engage in global governance processes? How to evaluate the outcomes?
In this workshop we will discuss the content of international tax standards and analyze the policy objectives and strategies pursued by different international, supranational and regional organizations, such as the United Nations, the OECD, the EU, among others, in the process. We will also pay attention to the challenges to the current structure of global governance due to the interactions between policy norms and legal instruments in the tax, trade and investment area.
In the first part, we will address how the global tax governance architecture has emerged and map the contemporary environment of international actors. Thereafter, we will discuss governance processes and actors involved in three case studies of specific policy areas: the role of the EU in the dissemination of BEPS standards, the taxation of the digital economy, and the introduction of a global minimum tax. In each case study, we will pay particular attention to the engagement of non-OECD countries with international institutions and the interaction between tax, trade and investment policy objectives and rules. In the final part of the workshop, we will discuss global tax governance under the lens of legitimacy and attempt to draw broader conclusions about the role of different actors in multilateral cooperation. Special attention will be given to the ongoing negotiation of the UN Framework Tax Convention and its two Protocols under the lens of legitimacy.
Procedure
Every session consists of lecture elements, input from ATAF, and general debates among all participants. In the lecture elements, the theoretical foundations will be exposed by Leiden University researchers. In the applied part, guest lecturers from ATAF discuss the topic based on examples from the region and based on ATAF’s experience in engaging in global tax governance. For the general debate, all participants are expected to actively participate and share their own experiences with the topic. To prepare for each session, all participants are requested to read the literature and complete the assignments.
February/March 2026 (t.b.c.) Programme available soon.
This seminar follows the Postgraduate online training The EU’s Global Regulatory Power and the EU Standard of Tax Good Governance. The training has been given in 5 sessions (every friday) from 17 of May 2024 until 14 of June 2024. A new training will be scheduled in the first semester of 2026
The seminar aims for a policy oriented outcome. We will provide some recommendations to policy makers in the EU Institutions, regional organizations in the Global South and countries that need to be considered when addressing the EU Standard of Tax Good Governance.
During the training the participants from mainly tax administrations in Africa, Asia, Latin America, and from Middle East and Europe some business, scholars, lawyers, presented a policy paper and/or a position paper. The 5 best papers will be presenting at this seminar.
Registration to the seminar is free and available to everyone. More details on registration link and programme available soon.