Marie Stoyanov

Marie Stoyanov


Marie is the Global Head of Arbitration and specialises in commercial and investment treaty arbitration. 

She has advised and represented clients in arbitrations throughout the world, both ad hoc and under all the major institutional rules, including the ICC, LCIA and ICSID Rules in which she has particular expertise. 

Marie has substantial experience across all market sectors but her practice focuses particularly on infrastructure, energy, and natural resource disputes, with expertise in disputes arising across the African continent. 

With clients that include both international investors and sovereign States, Marie regularly appears as advocate before renowned international tribunals arguing extremely complex cases, often with hundreds of millions of dollars at stake. Marie also sits as an arbitrator herself and has written and spoken regularly about international investment and arbitration. 

In addition, Marie has also advised various clients on how best to structure their investment in Africa, Eastern Europe and Asia, in order to take advantage of protections offered by investment treaties and foreign investment laws.

After graduating from ESSEC, Marie studied law and was admitted to the Paris bar in 2003. As a French qualified lawyer, she is naturally used to working in all civil-law environments, in particular those whose law is directly derived from French law (e.g. Algerian law, Egyptian law, Moroccan law, UAE law). 

A member of the Executive Board of the European Federation for Investment Law and Arbitration (EFILA), Marie is also an Advisory Board member of the publication Investment Claims, which is published by Oxford University Press.

Published Work

  • Sentence Micula : un tribunal condamne la Roumanie à payer 250 millions de dollars,, April 2014, written with Sebastiano Nessi
  • Enjeux et portée de la sentence Micula, Capital Finance, March 2014, written with Sebastiano Nessi
  • Interview - « Dès qu’un pays devient exportateur de capitaux, il est enclin à se porter vers l’arbitrage », Capital Finance, n° 1125, october 2013
  • Third-Party Funding in International Arbitration : Is it time for Some Soft Rules?, International Arbitration Review, June 2015, written with Olga Owczarek

Leadership Positions And Professional Affiliations

  • Executive Board member, European Federation for Investment Law and Arbitration (EFILA)
Marie Stoyanov has excellent advocacy skills and the ability to tackle complex cases.
Chambers Global, International Arbitration, 2024
Marie is an excellent arbitration lawyer. She was excellent in cross-examinations, smart and pleasant.
Chambers Global, International Arbitration, 2024


  • Global Leader, National Leader (France) and Thought Leader (France), Who’s Who Legal: Arbitration, 2024
  • Ranked as a Leading Individual for International Arbitration, Chambers (Europe-wide and France), 2024
  • Ranked as a Leading Individual for International Arbitration, Legal 500 (France), 2024
  • Ranked (four stars) for Arbitrage international - France, Option Droit & Affaires, 2023
  • Recognised practitioner - Arbitration and Mediation, « Best Lawyers », since 2020
  • “Leading Commercial & Investment Arbitrator of the Year 2019”, Acquisition International Magazine - France



Post Graduate Diploma, International Arbitration, Queen Mary University of London, 2003 

ESSEC Business School, 1997


French, English, German
A&O Shearman was formed on May 1, 2024 by the combination of Shearman & Sterling LLP and Allen & Overy LLP and their respective affiliates (the legacy firms). Any matters referred to above may include matters undertaken by one or more of the legacy firms rather than A&O Shearman.