Isabel Santos Fidalgo

She is active in corporate and international taxation, being widely recognised as one of the main references in Portugal in highly complex tax litigation, tax arbitration, taxation of energy and natural resources, structural corporate reorganisations, variable remuneration regimes for executives and social security taxation, as well as in advanced matters of tax governance of large economic groups. He regularly advises multinational groups, investment funds, public entities and family offices on transactions with significant economic impact and a strong strategic component, many of which are transnational in scope.

Throughout more than 25 years of practice, he has led paradigmatic tax proceedings in Portugal, including landmark litigation on IRC and social contributions, as well as tax structuring projects for oil concessions and investments in the energy sector in Portuguese-speaking African jurisdictions. She acts consistently before administrative courts and the Administrative Arbitration Centre (CAAD), where she also acts as a tax arbitrator. She is a member of corporate and foundation auditing bodies, with active involvement in governance, compliance and tax risk management matters.

She is a leading author in specialised legal publications, a regular speaker at national and international conferences and a guest lecturer on postgraduate taxation programmes. Her work has been repeatedly recognised by leading international directories.

She has been a member of Antas da Cunha Ecija since 2026.

Academic Background:

• Law Degree, Catholic University of Portugal (Porto School)
• Postgraduate in Business and Corporate Law, University of Coimbra
• Master’s in Law, Management and Enterprise, NOVA University Lisbon

Recognitions:

• Lawyer of the Year - Women in Business Law Awards EMEA 2022 - Tax Dispute Resolution
• Highly Regarded Practitioner in ITR World Tax - Tax Controversy

Languages:

• Portuguese
• English
• Spanish
• French
• German

Admission to the Portuguese Bar Association: 2004