TOMÁS MERSÁN RIERA

Partner
tomasmersan@mersanlaw.com
Biography

Lawyer graduated with honors from Universidad Católica “Nuestra Señora de la Asunción”, Master in Business Law and LL.M. from the University of Chicago Law School (2019). He has established himself as one of the most promising lawyers in tax, corporate and competition law in Paraguay, combining strong international academic training with a strategic practice focused on complex transactions and disputes.

He co-leads the firm’s tax and competition practices, participating in regulatory investigations, compliance program design and the structuring of transactions with a significant tax and corporate component. His approach combines economic analysis, structural efficiency and regulatory risk management.

He leads sophisticated tax planning mandates, corporate reorganizations, cross-border financing and binding consultations before tax authorities, with particular emphasis on fiscally efficient and regulatorily sustainable structures.

He is Professor of Tax Law, Director of the Paraguayan Institute of Law and Economics (IPDE) and Director of the International Fiscal Association (IFA) – Paraguay, actively participating in international congresses and specialized forums.

Practice Areas
  • Civil and Commercial Law.
  • Tax Law.
  • Corporate Law.
  • Competition Law.
  • Arbitration.
Education
  • Lawyer, 2013. Faculty of Legal and Diplomatic Sciences, Catholic University “Nuestra Señora de la Asunción”.
  • Master’s Degree in Business Law, 2016. Catholic University “Nuestra Señora de la Asunción”.
  • Master of Laws (LL.M.), 2019. University of Chicago Law School.
Languages
Spanish | English
Memberships and Associations
  • Paraguayan Bar Association.
  • Paraguayan Institute of Banking and Corporate Law (IPDBS).
  • Founding Member, Paraguayan Institute of Law and Economics (IPDE).
  • Founding Member, Paraguayan Fintech Chamber.
  • Founding Member, International Fiscal Association (IFA) – Paraguay.
Other Academic and Professional Activities
  • Author of the chapter “Theory of Piercing the Corporate Veil”, published in the collective work “Current Issues in Banking and Corporate Law – Monographs”, by the Paraguayan Institute of Banking and Corporate Law. Intercontinental, 2015.
  • Participant in the international arbitration and commercial law competition “Moot Madrid V”, organized by Universidad Carlos III and the United Nations Commission on International Trade Law (UNCITRAL/CNUDMI), 2013.
  • Participant in the international arbitration competition “Willem C. Vis International Commercial Arbitration Moot”, 2014.
  • Coach of the arbitration team of the Catholic University “Nuestra Señora de la Asunción” for international arbitration competitions organized by the University of Buenos Aires and the University of Rosario (Bogotá); Santiago, Chile, 2015 and Montevideo, 2016.
  • Director, Paraguayan Institute of Law and Economics (IPDE), 2024–2025.
  • Professor of Tax Law, Catholic University “Nuestra Señora de la Asunción”.
  • Contributor to the publication “Introduction to the Economic Analysis of Law – Paraguayan Edition”, La Ley, 2018.
  • Arbitrator, Arbitration and Mediation Center of Paraguay (CAMP).
  • Director, Paraguayan Fintech Chamber, 2025–2026.
  • Director, International Fiscal Association (IFA) – Paraguay.