Who's Who Legal
Who's Who Legal
New to Who's Who Legal?
New to Who's Who Legal?
User Menu
New to Who's Who Legal?
Thought Leaders

Thought Leaders

Thought Leader

WWL Ranking: Thought Leader

Global Leader

Arbitration 2021

Professional Biography

WWL Ranking: Recommended

Peers and clients say

"I found Claudia to be highly competent counsel who was well prepared and able to put forward cogent and persuasive arguments"
"She is very well regarded in investment arbitration area" "She is simply terrific"


Claudia Annacker is a partner at Dechert LLP in Paris.  She focuses her practice on international arbitration and public international law matters, in particular investor-State disputes, inter-State disputes, disputes involving international organizations, and human rights cases.  She has represented States, State-owned entities and private investors in more than thirty investment arbitrations, under bi- and multilateral investment treaties, investment contracts, and domestic investment legislation, and under all major arbitration rules.

Claudia’s recent investment arbitration expertise includes the representation of the Hellenic Republic in an ICSID arbitration under the Hellenic Republic-Slovak and Hellenic Republic-Cyprus bilateral investment treaties, concluding with a landmark award dismissing all claims for lack of jurisdiction over sovereign bonds, the Republic of Austria in an ICSID arbitration under the Austria-Malta bilateral investment treaty, resulting in the dismissal of all claims for lack of jurisdiction, and the Arab Republic of Egypt in an ICSID arbitration brought under the US-Egypt BIT, with all claims being dismissed for lack of jurisdiction or on the merits.  Her arbitration experience includes matters related to the oil and gas, energy, banking, financial services, port operation, telecommunication, and tourism sectors, and sovereign debt.  She also has particular expertise in investment arbitrations involving sovereign investments.

Holding a Ph.D. and venia legendi et docendi (habilitation) in public international law, she regularly advises States, State entities, international organizations and multinational corporations on public international law matters, including the law of treaties, State responsibility, human rights, State immunity, diplomatic and consular immunities, immunities of international organizations, State succession, the law of the sea and international trade law.

Claudia also acts as arbitrator, having first been appointed by the ICC at the age of 33.  She currently serves as a member of the SIAC Court of Arbitration and the board of the Vienna International Arbitral Centre.

She is an adjunct professor at the University of Vienna where she teaches advanced research seminars in international dispute settlement and international responsibility, and has also been a visiting professor at the University of Paris X (Nanterre).  She also teaches at the National University of Singapore, Fudan University and the National Academy of Legal Studies and Research, Hyderabad.

Claudia has published extensively on international arbitration and public international law topics, including the role of the investor’s legitimate expectations in defending against investment treaty claims, the protection and admission of sovereign investment under investment treaties, investment treaty arbitration as a tool to “enforce” arbitral awards, investment treaty protection in Arab countries, China, and Japan, the International Law Commission’s Draft Articles on Responsibility of States for Internationally Wrongful Acts, erga omnes obligations in international law, and ultra vires acts of international organizations.

National Leader

WWL Ranking: Recommended
Law Business Research
Law Business Research Ltd
Meridian House, 34-35 Farringdon Street
London EC4A 4HL, UK
© Law Business Research Ltd 1998-2020. All rights reserved.
Company No.: 03281866