TOMÁS MERSÁN RIERA

Partner
tomasmersan@mersanlaw.com
Biography

A law graduate with honors from the Universidad Católica «Nuestra Señora de la Asunción,» with a Master’s degree in Business Law and an LL.M. from the University of Chicago Law School (2019). He has established himself as one of the most promising attorneys in tax, corporate, and antitrust law in Paraguay, combining a solid international education with a strategic practice focused on complex transactions and disputes.

He co-leads the firm’s tax and antitrust practices, participating in regulatory investigations, designing compliance programs, and structuring transactions with significant tax and corporate implications. His approach combines economic analysis, structural efficiency, and regulatory risk management.

He leads complex tax planning projects, corporate reorganizations, cross-border financing, and binding rulings from tax authorities, with a particular focus on tax-efficient and regulatory-compliant structures.

He is a professor of tax law, director of the Paraguayan Institute of Law and Economics (IPDE), and director of the International Fiscal Association (IFA) – Paraguay, and actively participates in international conferences and specialized forums.

Practice Areas
  • Civil and Commercial Law.
  • Tax Law.
  • Corporate Law.
  • Antitrust.
  • Arbitration.
Education
  • Lawyer, 2013. School of Legal and Diplomatic Sciences, “Nuestra Señora de la Asunción” Catholic University.
  • Master’s Degree in Business Law, 2016. “Nuestra Señora de la Asunción” Catholic University.
  • 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 anthology *Current Issues in Banking and Corporate Law – Monographs*, by the Paraguayan Institute of Banking and Corporate Law. Intercontinental, 2015.
  • Participant in the “Moot Madrid V” international arbitration and commercial law competition, organized by Carlos III University and the United Nations Commission on International Trade Law (UNCITRAL), 2013.
  • He also participated in the “Willem C. Vis International Commercial Arbitration Moot” competition in 2014.
  • Coach of the refereeing team at the Universidad Católica “Nuestra Señora de la Asunción” for international refereeing competitions organized by the University of Buenos Aires and the Universidad del Rosario in Bogotá; Santiago, Chile, 2015, and Montevideo, 2016.
  • Director, Paraguayan Institute of Law and Economics (IPDE), 2024–2025.
  • Professor in the Department of Tax Law, «Nuestra Señora de la Asunción» Catholic University.
  • Contributor to the book *Introduction to the Economic Analysis of Law – Paraguayan Edition*. La Ley, 2018.
  • Arbitrator, Paraguayan Center for Arbitration and Mediation (CAMP).
  • Director, Paraguayan Fintech Chamber, 2025–2026.
  • Director, International Fiscal Association (IFA) – Paraguay.