Executive Board

Natalia Quiñones is the current President of the International Fiscal Association (IFA) and an international tax partner at Quiñones Cruz in Bogotá, Colombia. She was an advisor to the Colombian Minister of Finance on international taxation until August 2024. Until January 2020, she was director of the Office of International Affairs at the National Tax and Customs Directorate (DIAN).

She is a PhD candidate in Tax Law at the University of Amsterdam (UvA). She holds a law degree from the Universidad del Rosario, a philosophy degree (summa cum laude) from the Universidad de los Andes, and a Master of Laws (Gerard Wallace Scholar) from New York University (NYU).

She is a member of the IFA's Permanent Scientific Committee and the board of directors of the Colombian branch of the IFA, which she chaired until July 1, 2020. She currently teaches international taxation at the University of Los Andes and is a guest lecturer at various venues worldwide.

Global Head of Tax, Siemens AG
Global Head of Tax and Corporate Vice President at Siemens since 2009, based in Munich, 
responsible for the global Siemens team of 690 tax and customs experts. Christian is the Vice 
President and member of the executive board of Global IFA (since 2025). He is the co-chairman of the BIAC Tax Committee (since 2025), chairman of the tax commission of the German Federation of Industries (BDI) (since 2021), chairman of the supervisory board of WTS AG (since 2009) and member of the advisory council of the Belt and Road Administration Cooperation Mechanism (BRITACOM – since 2020). 

Alexia Kardachaki is the Secretary-General and Head of Secretariat of Global IFA. She is an international and EU tax lawyer and, prior to joining Global IFA, held senior positions in international tax advisory and law firms (Lubbers, Boer & Douma, PwC, KPMG Meijburg & Co), industry (LyondellBasell), and business groups (European Business Tax Forum). She holds (tax) law degrees/diplomas from the National and Kapodestrian University of Athens, Athens University of Economics and Business, Vienna University of Economics and Business, Vrije Universiteit Amsterdam, and the University of Lausanne.  

She was the IFA research associate in 2012-2013 and national reporter for the IFA Cahiers in 2014 (for Greece) and in 2022 (for the Netherlands). She is one of the founding members of the Women of IFA Network in the Netherlands and has served as a board member of the Dutch IFA Branch (2021-2024). She was a member of the Organizing Committee of the 3rd IFA European Region Conference, which took place in Amsterdam in 2023. 

With a passion for (international) tax policy Edwin works at the interface where tax policy, the business and clients meet. Edwin is dep. Global Tax policy leader at PwC and has a specific focus on EU Tax Policy.His practice includes representing PwC in tax policy matters (e.g. with the EU institutions and the OECD), sharing his and PwC’s vast experience and insights in policymaking to help improve tax, legal and regulatory systems for the future. He provides strategic advice to boardrooms to help shaping sustainable tax strategies, and is involve tax government consulting (advising governments on tax matters). 

Edwin brings 26 years of experience in the Dutch government. He was deputy director-general for Tax and Customs Policy and Legislation and Director for Direct Taxes at the Dutch Ministry of Finance. He represented the Netherlands in the Bureau of the OECD’s Committee on Fiscal Affairs from 2012 through 2014 and he co-chaired the OECD Informal task force on tax and development (2010-2014). Edwin was director for International Tax Policy and Legislation from January 1, 2009 to March 1, 2012. Before that he was responsible for a coordinated treatment of the 2000 largest companies in the Netherlands by the Netherlands’ Tax and Customs Administration (NTCA) and also head of the transfer pricing division of the NTCA. 

Dr. Adolfo Martín Jiménez is a Professor of Tax Law at the University of Cádiz (Spain) and the author of several books and over one hundred articles on international and EU tax law. He has extensive practical experience—including involvement in disputes and arbitrations—in international taxation, EU tax law, and transfer pricing. Dr. Martín Jiménez frequently serves as a consultant for multinational groups, law firms, governments, and major international organizations in the field of international taxation. He currently serves as Chairman of the Permanent Scientific Committee of the International Fiscal Association and was a former Chairman of the European Association of Tax Law Professors.