Diana Tsutieva

Partner

Direct: 202.677.4060
Washington
2100 Pennsylvania Avenue NW
Suite 350S
Washington, District of Columbia 20037

Biography

Diana is a partner and chair of the firm’s International Dispute Resolution practice. With over 15 years at the forefront of high-stakes international disputes, Diana represents sovereign states and state-owned entities, as well as private clients in investor-state arbitration, international commercial arbitration, public international law matters, and litigation in U.S. federal courts. Her work spans Latin America, Europe, Central and South Asia, and beyond across the energy, natural resources, infrastructure, financial services, healthcare, waste management, and other sectors. Dual-qualified in both the United States and France, Diana has built particular experience across Eurasia and Central Asia, advising governments, state-owned enterprises, and foreign investors on complex disputes, investment treaty reform, and cross-border legal strategy.

Diana represents states, state-owned entities, and corporations in investment treaty disputes, international commercial arbitrations, and public international law matters before all major arbitral fora (ICSID, UNCITRAL, ICC, etc.), the International Court of Justice (“ICJ”), and specialized regional human rights fora, including the African Commission on Human and Peoples’ Rights.

She has successfully defended European, Eurasian, and Latin American states in investor-state arbitrations resulting in jurisdictional victories, complete victories on liability, and reductions of claimed damages by more than 90%. She has also represented sovereign states in enforcement proceedings in U.S. courts, involving the issues under the U.S. Foreign Sovereign Immunities Act (“FSIA”) and the New York Convention. Diana developed substantial experience handling environmental issues in investor-state arbitration and advised states on climate change-related treaty reforms. She also advises clients on a wide range of public international law matters, including cultural heritage and cultural property, privatization of state-owned assets, sanctions, and international trade.

Diana sits as an arbitrator in international commercial proceedings, having served as sole arbitrator and co-arbitrator in cross-border disputes. In addition to her arbitration practice, Diana represents and advises clients in U.S. litigation involving arbitral award enforcement, transborder disputes, and discovery abroad.

Before joining AGG, Diana was a partner at an Am Law 200 firm in Washington, D.C., and earlier practiced at a major international law firm in Paris, France, where she represented multinational corporations in M&A transactions and advised on matters under French, EU, and U.S. law, experience that she puts to practical advantage in disputes settings. She also served as a judicial clerk to the Honorable Judith M. Barzilay at the U.S. Court of International Trade. She is fluent in English, French, and Russian, enabling her to work directly with clients, government officials, and co-counsel across Eurasia, Central Asia, Europe, Africa, and the Americas without the need for intermediaries.

Diana services her clients with top-tier experience and direct hands-on engagement, using innovative strategies and focused teams. Her linguistic fluency combined with deep familiarity with the legal and cultural landscape of Europe, Latin America, Eurasia, and Central Asia, makes her an effective advocate for clients operating in those regions. She has been recognized in Who’s Who Legal: Arbitration and Lexology: Arbitration as a Future Leader, earning “widespread international praise” for her work on complex investment and commercial arbitration matters. Diana is a frequent speaker and author on international arbitration, investment treaty reform, environmental disputes, and emerging issues at the intersection of international law and climate change.

Related Services

Related Markets

Experience

Investor-State Arbitration
  • Chevron/Texaco v. Ecuador (UNCITRAL) Co-lead counsel to the Republic of Ecuador in the damages phase of a landmark investment arbitration under the Ecuador-U.S. BIT arising from a massive environmental litigation. Led the team on all international law issues; secured a 93.4% reduction in damages, following a liability phase handled by another firm, avoiding over $3.13 billion in liability for Ecuador; successfully pursued a correction request under the UNCITRAL Rules, securing a further $5.7 million reduction.*
  • Merck Sharpe & Dohme v. Ecuador (UNCITRAL) Counsel to the Republic of Ecuador in arbitration under the Ecuador-U.S. BIT arising from the alleged treatment of a foreign investor by the Ecuadorean judiciary. Secured a significant reduction in damages and settlement.*
  • Murphy Exploration v. Ecuador (UNCITRAL) Counsel to the Republic of Ecuador in arbitration under the Ecuador-U.S. BIT arising from changes in domestic legislation pertaining to the exploitation of oil resources. Secured a 96% reduction in claimed damages of $633 million sought by Murphy.*
  • Louis Dreyfus Armateurs v. India (UNCITRAL) Counsel to the Republic of India under the India-France BIT concerning the supply and operation of cargo handling equipment in West Bengal. All claims dismissed; tribunal awarded India $7.2 million in costs.*
  • Niko Resources v. Bangladesh (ICSID) Counsel to Bangladesh and its State entities in a dispute concerning the causes and impacts of two gas blowouts. Secured environmental and gas loss compensation for Bangladesh.*
  • Ping An v. Kingdom of Belgium (ICSID) Counsel to Belgium in ICSID arbitration under the China-Belgium BIT arising from measures in the financial services sector. Secured full victory on jurisdiction.*
  • Achmea v. Slovak Republic (UNCITRAL) Counsel to the Slovak Republic in arbitration under the Netherlands-Slovak Republic BIT concerning health insurance sector measures. Secured full victory on jurisdiction.*
  • European American Investment Bank v. Slovak Republic (UNCITRAL) Counsel to the Slovak Republic in arbitration under the Austria-Czech and Slovak Republic BIT. Secured full victory on jurisdiction.*
  • Anglo American v. Venezuela (ICSID Additional Facility) Counsel to Venezuela against a UK mining company concerning termination of a nickel concession.*
  • Gold Reserve v. Venezuela (ICSID Additional Facility) Counsel to Venezuela against a Canadian gold mining company concerning gold concessions and environmental rights.*
  • Vannessa Ventures v. Venezuela (ICSID Additional Facility) Counsel to Venezuela under the Canada-Venezuela BIT arising from cancellation of a gold mining contract. Tribunal found Venezuela not liable.*
  • Sanitek v. Armenia (ICSID) Co-lead counsel to the Republic of Armenia under the Lebanon-Armenia and Canada-Armenia BITs relating to claims under two waste management concessions.*
  • Chevron Bangladesh v. Bangladesh (ICSID) Counsel to Bangladesh State entities in ICSID arbitration involving oil and gas exploration matters.*
    Recognition & Enforcement — U.S. Federal Courts
    • Kingdom of Spain — Four Proceedings Represented the Kingdom of Spain in four separate U.S. federal court proceedings defending against enforcement of arbitral awards: (1) €112 million ICSID award (D.D.C.); (2) €39 million Stockholm Chamber of Commerce award under the New York Convention (S.D.N.Y.); (3) €53 million Stockholm Chamber of Commerce award (D.D.C.); and (4) €64 million ICSID award (D.D.C.). Total value defended: over €268 million.*
      Commercial Litigation — U.S. Federal Courts
      • Actava TV v. Channel One Russia et al. (S.D.N.Y.) Counsel to plaintiffs in civil litigation (18-cv-06626) involving claims of malicious prosecution, tortious interference with prospective economic advantage, and unfair competition under New York General Business Law § 349. Secured a jury verdict in the amount of $4.5 million to the client.*
        Sovereign Advisory & Investment Treaty Counseling
        • Republic of Uzbekistan: Advised on the development of Uzbekistan’s model Bilateral Investment Treaty and related domestic laws designed to attract foreign investment while safeguarding State interests. Delivered annual government training programs on investment treaty arbitration, commercial arbitration and U.S. law to the Ministry of Justice of Uzbekistan, most recently in February 2026 at the Training Institute for Lawyers under the Ministry of Justice of the Republic of Uzbekistan.*
        • Republic of Kazakhstan: Advised on improving the texts of existing BITs between Kazakhstan and third countries; delivered capacity training for government officials on related topics.*
        • UzAssets: Advised UzAssets in connection with the privatization of State-owned assets in Uzbekistan in two projects.*
        • Republic of Turkmenistan: Advised the Ministry of Foreign Affairs on the prospective reforms of Turkmenistan’s foreign investment law in a project sponsored by USAID.*
        • UNCITRAL Working Groups: Advised several States on their interventions before UNCITRAL working groups relating to reforms in international investment arbitration.*
          State-to-State Proceedings
          • Croatia v. Slovenia Counsel to the Republic of Croatia in ad hoc arbitration under the aegis of the European Commission concerning the delimitation of land and maritime boundaries between the two States.*
          • Djibouti v. Eritrea Counsel to the Republic of Djibouti before the African Commission on Human and Peoples’ Rights in an inter-State proceeding involving Eritrea’s detention of Djiboutian prisoners of war.*
            Pro Bono Matters
            • COP Climate Negotiations: Advise small island and developing states on negotiating positions and legal strategy in connection with Conference of the Parties (“COP”) climate negotiations.*
            • Afghanistan — Gender Apartheid & Women’s Rights: Legal counsel to Afghan human rights defenders, in coordination with the Atlantic Council Strategic Litigation Project and the Civic Engagement Project, in efforts to codify the crime of gender apartheid and advance international accountability measures for the rights of women and girls in Afghanistan.*
            • UN Working Group on People of African Descent: Represented the WGEPAD in an amicus brief filed before the Inter-American Human Rights Commission challenging U.S. felony disenfranchisement laws based on their disproportionate impact on people of African descent.*
              Arbitrator Appointments
              • Sole arbitrator in a cross-border sale-of-goods dispute between parties from Russia and Singapore (TIAC 12/2025), Tashkent International Arbitration Centre.*
              • Sole arbitrator in a cross-border sale-of-goods between parties from Russia and Singapore (MKAS 23/2024), International Commercial Arbitration Court at the Chamber of Commerce and Industry of the Republic of Uzbekistan.*
              • Co-arbitrator in a sale-of-goods dispute involving parties from Uzbekistan and Russia (MKAS 5/2024), International Commercial Arbitration Court at the Chamber of Commerce and Industry of the Republic of Uzbekistan.*
              • Co-arbitrator in a sale-of-goods and construction dispute involving parties from Hong Kong, China and Uzbekistan (MKAS 23/2023), International Commercial Arbitration Court at the Chamber of Commerce and Industry of the Republic of Uzbekistan.*

              *Representative matters handled while practicing at another law firm.

                Credentials

                Education
                • Rutgers University School of Law, Juris Doctor
                • University of Paris I: Panthéon-Sorbonne, LL.M. – European Union & French Laws
                • Cornell University, Bachelor of Arts – Comparative Literature
                Admissions
                • District of Columbia
                • State of New York
                • State of New Jersey
                • Barreau de Paris (France)
                Associations
                  • American Bar Association, Section of International Law
                    • Eurasia/Russia Committee, Co-Chair, 2018-22
                    • Eurasia Committee, Chair, 2022-23
                  • American Society of International Law
                    • Dispute Resolution Interest Group Co-Chair, 2018-21
                    • ISDS Reforms Working Group, Founding Chair, 2018-21
                  • American-Uzbek Law Association, Steering Committee Member, 2026
                  • Tashkent International Arbitration Centre (“TIAC”), Reserve Panel of Arbitrators
                Languages
                • Russian ( Fluent )
                • French ( Fluent )

                Recognition

                • Who’s Who Legal: Arbitration, Future Leader, 2017-24
                • Lexology: Arbitration, Future Leader, 2026

                Thought Leadership & Speaking Engagements

                Thought Leadership

                • “The Rise of Climate Change-Related and Environmental Provisions in Investment Treaties,” International Comparative Legal Guide — Investor-State Arbitration, 2025.
                • Co-author, “The Future of Investor-State Dispute Settlement under the Energy Charter Treaty,” Kluwer Arbitration Blog, March 2021.
                • Co-author with Mark A. Clodfelter, “Counterclaims in Investment Arbitration,” in Katia Yannaca-Small, Arbitration Under International Investment Agreements: A Guide to the Key Issues (2nd ed., Oxford University Press), 2018.
                • Co-author, “Transparency in Arbitration,” Practical Law, Winter 2018.
                • Co-author with John Shope, “Summary Disposition in Arbitration,” Today’s General Counsel, Winter 2018.

                Speaking Engagements

                • Lecturer, “International Investment Agreements; Investment Contracts; and AI in International Arbitration — Training Institute for Lawyers,” Ministry of Justice of Uzbekistan, November 2025.
                • Speaker, “Mega Arbitration Disputes in Central Asia: Where the West, Russia, China, and the Middle East Meet,” ICC YAAF, October 2025.
                • Speaker, “Arbitration in Disputes About Energy, Construction & Climate Change,” Baltic Arbitration Days, June 2024.
                • Speaker, “Resolving Disputes Arising from Climate Change, Peace, and Security,” Paris Arbitration Week, March 2023.
                • Speaker & Panelist, “Alternative Dispute Resolution from Mediation to Arbitration,” Tashkent Law Spring Forum, May 2023.
                • Moderator, “Disputes Arising from Sanctions and National Security Issues,” Baltic Arbitration Days Pre-Conference Roundtable, June 2023.
                • Speaker, “Sanctions Compliance,” Astana International Financial Centre (“AIFC”) Academy of Law, April 2023.
                • Speaker, “Investment Dispute Resolution,” Astana International Financial Centre (“AIFC”) Academy of Law, February 2023.
                • Speaker, “Foreign Investment Laws — A Renewed Basis for Consent to International Investment Arbitration,” Washington Arbitration Week, December 2021.
                • Moderator, “Innovative Defense Strategies in ISDS,” Uzbek Arbitration Week, September 2021.
                • Moderator, “Protecting Human Rights Through International Adjudication,” ASIL Annual Meeting, June 2020.
                • Lecturer, “Bringing Counterclaims,” Executive Training on Investment Arbitration for Government Officials, 2017, 2018.
                • Speaker, “Raising Jurisdictional Objections” and “Bringing Counterclaims,” Investor-State Arbitration Seminar, May 2018.
                • Speaker, “Populism and International Trade Law,” Harvard International Law Journal Symposium, March 2019.