1. Skip to navigation
  2. Skip to content
  3. Skip to sidebar

About us

Welcome to The Ex'tax Project

The Ex'tax Project believes that humanity can flourish by saving natural resources and tapping into the abundance of human capital instead, by developing the capacities and talents of people. This kind of prosperity would last generation after generation. 

In order to get there, we do need to change the 'rules of the game' and give room for an inclusive circular economy. As taxes play such an important role in steering the economy, it's common sense to start there.

The Ex’tax Project Foundation is an independent think tank that strives towards a fundamental tax shift from labour to natural resource use. Ex'tax is based on the legacy of Dutch entrepreneur Eckart Wintzen (1939-2008). 

The foundation raises support and creates alliances and practical tools that help advance the implementation of Ex'tax around the world.



- Lecture series in San Jose, Costa Rica
- Ex'tax central in ICMAB Continuing Professional Development Program Aligning tax policy – A Case study on Bangladesh Dhaka, Bangladesh
- ACCA Pakistan, Islamabad webinar
ACCA & Deloitte event on Tax as a Force for Good, Brussels
- Ex'tax part of Columbia University Curriculum (second year)
- Webinar attended by 235 Canadian finance professionals
- Panel in Davos side-event to the World Economic Forum


- ACCA discussion paper Tax as a force for good: rebalancing our tax systems to support a global economy fit for the future
- Finland study: Aligning fiscal policy with the circular roadmap in Finland
- Webinar attended by 2,100 finance professionals from 107 countries
- Mention in OECD Taxing Energy Use 2018 report
- Panel at side event World Economic Forum Davos
- Presentations at the Ministry of Foreign Trade, the Chamber of Industries and the Dutch Embassy in San José, Costa Rica
- Ex’tax part of the Columbia University (New York) Circular Economy for Sustainability Professionals program
- Interview Café Weltschmerz (in Dutch)

-> Update January-April 2018 [pdf]



- Ex’tax played a role in the 2017 elections in the Netherlands as political parties, scientists, NGOs and businesses called for the tax shift. Four Liberal and Christian parties (VVD, CDA, D66 and ChristenUnie) were able to form a new government and in their Agreement 2017-2021 the coalition included policy action towards shifting the tax burden from labour onto natural resource use.
- Ex'tax was mentioned in 
The Portugese Council of Ministers Resolution Action plan for circular economy in Portugal: 2017-2020.
- Ex'tax was mentioned in the OECD report for the G7 Environment Minister
- Ex'tax was mentioned in various publications and presentations by The Ellen MacArthur Foundation, the Club of Rome, Allen & Overy, KPMG and PGGM (a € 183 billion asset manager).
- The Ex'tax Project presented in the OECD Seminar series New Approaches to Economic Challenges and in a panel at the OECD Forum
- Ex’tax is included in the Columbia University (New York) curriculum on the Circular Economy.
- Lectures in Porto, Lisbon, Amsterdam, Rotterdam, Paris, Geneva, London and Brussels
- New Dutch Masters lecture at Dutch Permanent Representation in Geneva
- More than 400 organisations and companies call for Dutch government to implement the tax shift: Duurzaam Regeerakkoord
- Blog: Rise of the Machines: Who will pay tax in future?
- Blog KPMG Responsible Tax: Smart taxation – a key force in achieving UN Global Goals
- Blog Circulate: Three Steps to Jumpstart the Circular Economy
- World Economic Forum Davos

-> Update September - December 2017 [pdf]
-> Update February-April 2017 [pdf]
-> Update December 2016-February 2017 [pdf]


- Publication: New era. New plan. Europe. A fiscal strategy for an inclusive, circular economy in cooperation with Deloitte, EY, KPMG Meijburg, PwC, Cambridge Econometrics, Trucost
- The Ex'tax Project honoured as Dutch Iconic Circular Project
- TEDxUtrecht
- Inter American Development Bank Washington 

-> Update February-November 2016 [pdf]


- Advising the Finance Committee of the Dutch House of Representatives on the Tax Review
- Ex’tax makes it into European Parliament Resolution
- Presentation WBCSD Montreux
- Presentation World Resources Forum Davos
- Blog Circulate: The Social Power of the Circular Economy

-> Update December 2015-January 2016 [pdf]
-> Update July-November 2015 [pdf]
-> Update January-June 2015 [pdf] 


- Publication: New era. New plan. Fiscal reforms for an inclusive, circular economy. Case study the Netherlands in cooperation with Deloitte, EY, KPMG Meijburg, PwC
- Blog Huffington Post: Tax Shift Is Key to a Circular Economy and Jobs
- Blog Huffington Post: How Taxes Can Save the World
- Presentation European Commission Green Week Brussels

-> Highlights 2014 & Outlook 2015 [pdf]
-> Highlights 2013 & Outlook 2014 [pdf]



The Ex'tax Project is supported by The DOEN Foundation. DOEN promotes sustainable, cultural and social innovation. Ex'tax and DOEN share fundamental goals; to combat climate change, to cultivate an open society based on cohesion and to promote the Green and Inclusive Economy. 

The Ex'tax Project is also supported by Adessium Foundation, a private foundation based in the Netherlands that aspires to a world in which people live in harmony with each other and with their environments.

MAVA Foundation also supports The Ex'tax Project. MAVA Foundation is a family-led, Swiss-based foundation with an exclusive focus on the conservation of biodiversity.

The Ex'tax Project is a Dutch ANBI Foundation.



The Ex'tax Project

Fortweg 9
3992 LX Houten
The Netherlands
T +31 (0) 34 349 21 00
Map icon Plan your route with Google Maps

Our people


Femke Groothuis photo
Femke Groothuis

President & Wavemaker

Since 1999, Femke has worked with Eckart Wintzen and Ex'tent, pioneering in green and social investment. This inspired her to start the Ex’tax 'wave' in 2009. Being a political scientist in the field of international relations and environment helps her keep the big picture.

Femke on LinkedIn

Peter Gersen photo
Peter Gersen


Peter is media and communication specialist. As a former journalist, producer and director in the world of television and web, he has learned how to strategically convey a message. He now uses his experience, network and talents to fight the good fights.

Peter on LinkedIn

Valérie van de Luitgaarden photo
Valérie van de Luitgaarden

Research & Production

Valérie on Linkedin

Feike Sijbesma photo
Feike Sijbesma


Feike is CEO of Royal DSM, Climate Leader for the World Bank Group and Co-Chair of the High Level Assembly of the Carbon Pricing Leadership Coalition (CPLC), convened by the World Bank. Feike also serves as Member of the Global CEO Council (GCC) Chinese People's Association for Friendship with Foreign Countries (CPAFFC).

Bram Zwagemaker photo
Bram Zwagemaker

Chairman of the Board

Bram is a seasoned business and financial specialist. Bram was CFO of BSO/Origin when the company published its ground-breaking 1990 environmental report and he has supported the Ex'tax concept ever since. Currently, Bram is director at Ex'tent.

Kees van Boxel photo
Kees van Boxel

Member of the Board

Kees van Boxel has 30 years of experience in the field of taxation and business. Until July 2013, Kees was Managing Partner of Tax advisory at Ernst & Young. He has worked with a wide range of family owned companies and multinationals.

Wendy van Ierschot photo
Wendy van Ierschot

Member of the Board

Wendy is human resources specialist. She is the Founder & CEO of Van Ierschot BV (HR co-sourcing & HR consultancy). In 2015 Van Ierschot BV was listed as 'FD Gazelle', as one on the fastest growing companies in the Netherlands. In 2014, Wendy won the Enterprising Women of the Year Award (U.S.).

Prince Carlos de Bourbon de Parme photo
HRH Prince Carlos de Bourbon de Parme


HRH Prince Carlos de Bourbon de Parme is member of the supervisory board of ASN Bank and board member of MVO Nederland (a CSR association). He builds bridges for sustainability between government, politics and NGOs, in the Netherlands, Italy and Spain.



Herman Wijffels photo
Herman Wijffels


Prof. Dr. Wijffels is professor of Sustainability and Social Change at University of Utrecht. Previously, he was the Dutch representative at the World Bank, chairman of the Dutch Social-Economic Council and chairman of the board of directors of Rabobank.


Gail Whiteman photo
Gail Whiteman


Gail Whiteman is a professor of business society management at Rotterdam School of Management, Erasmus University (RSM) and Professor in-Residence at the World Business Council for Sustainable Development (WBCSD).  She is co-founder and Director of ERIM's Centre for Corporate Eco-Transformation.


Wouter van Dieren photo
Wouter van Dieren


Wouter van Dieren is a renowned sustainability expert and, amongst others, member of The Club of Rome and of the World Academy for Arts and Sciences.


Paul Dickinson photo
Paul Dickinson


Paul Dickinson is founder and Executive Chair of CDP, which collects data on greenhouse gas emissions, water and forest use. Over 3,700 of the largest companies in the world, and 73 cities with total 244 million inhabitants report through the CDP system.


Paul Ekins photo
Paul Ekins


Paul Ekins is Professor of Energy and Environment Policy at UCL and a member of UNEP's International Resource Panel. He is an authority on energy-environment-economy (E3) interaction and environmental policy, including taxation.

Annemieke Roobeek photo
Annemieke Roobeek


Annemieke Roobeek is professor of Strategy and Transformation Management (Universiteit Nyenrode, since 1997) and member of the Supervisory Board of ABN AMRO Group. She is director and owner of MeetingMoreMinds, an organisation to accelerate learning, innovation and professional development among innovative companies.

Clien Wintzen photo
Clien Wintzen


Clien Wintzen has been involved with The Ex'tax Project from the very start. Proud of her fathers Eckart Wintzens legacy she helps our organisation with focus and always keeping the bigger picture in mind.