World Law Alliance

Mario Oller

Mario Oller

Founding Partner

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Profile Overview

Mario is one of the founder partners of the firm, with a degree in Law from the University of Barcelona and a postgraduate degree in Legal Practice from the Barcelona Bar Association,

specializing in Litigation, Civil and Criminal Law.


His practice has focused on real estate law, banking law and civil liability claims. After working in various small and medium-sized law firms, he has spent most of his professional career as head of the legal department of the family firm, founded in 1951.


He advises individuals and companies on the development, acquisition and financing of all types of real estate projects, designing investment strategies with high returns. He has extensive experience in contractual matters, leases and horizontal property, and knows the real estate market and has advised and mediated in countless asset purchase and sale transactions.


A keen litigator, he regularly represents clients of the firm before the Courts of First Instance and Tribunals. Having studied primary school at the Lycée Français in Barcelona, Mario is bilingual in French and speaks English, Portuguese, Spanish and Catalan.