The Legal 500

Twitter Logo Youtube Circle Icon LinkedIn Icon

Aceris Law

Work +41 22 819 1812
Geneva, Paris
Aceris Law, William Kirtley, Geneva, SWITZERLAND

William Kirtley

Work +41 78 611 9019
Aceris Law

Work Department

International Arbitration


Partner at Aceris Law LLC

The international arbitration lawyer William Kirtley, principal of Aceris Law LLC, is a Franco-American Harvard, Columbia and Sorbonne-trained lawyer with seventeen years of experience specialising in international commercial arbitration, investor-State arbitration and international construction arbitration. He is a member of the New York Bar, the Washington Bar and an Avocat au Barreau de Paris (en omission). He has served as arbitration counsel or arbitrator in disputes on all continents, under the UNCITRAL, ICC, ICSID, SCC, LCIA, JAMS, ICDR, CICA, CIArb, PCA, SIAC, DIAC, AFA and other arbitration rules.

Previously a Partner at a well-regarded Paris arbitration boutique, he was a member of the international arbitration practice groups of Shearman & Sterling and Salans (now Dentons) in Paris, after serving as an American Peace Corps Volunteer for two years in the Ivory Coast and working at the United Nations International Criminal Tribunal for Rwanda.

He has served as lead counsel in dozens of international commercial, construction and investment arbitrations and has authored numerous academic articles concerning international arbitration in leading journals. He is a member of the International Arbitration Institute, regularly speaks on international dispute resolution topics, has taught at the Universities of Paris X and Paris II – Assas-Panthéon for many years, is a co-founder of the IAA Network and has served as an expert for the World Bank on ADR legislation.


Aceris Law – Partner

Partner at the arbitration boutique Aceris Law, focusing on commercial, investment and construction arbitrations, as well as public international law disputes. Has served as lead counsel for both Claimants and Respondents in ICC, LCIA, ICSID, SCC, UNCITRAL, SIAC, ICDR, JAMS, SCC and other ad hoc arbitrations, for both private clients and State entities, under public international law, English law, Swiss law, French law, Turkish law, United Arab Emirates law, Moldovan law, Singapore law, Malaysian law, Mexican law, Mauritanian law, various American laws (including the laws of California, Texas and Washington), Canadian law, Saudi Arabian law, Liberian law, Spanish law, Brazilian law, Angolan law, OHADA law, German law, Hong Kong law, Albanian law, Bulgarian law, Filipino law, Japanese law, Russian law and Romanian law, amongst others. He has also served as arbitrator in disputes under the ICC and DIAC rules of arbitration. Mr. Kirtley spends half of his time in Geneva and a quarter of his time in Paris and London, respectively.

DK AARPI – Partner

Partner at the international arbitration boutique law firm DK AARPI with a former partner from Shearman & Sterling. Served as international arbitration counsel in multiple ICC, ICSID, UNCITRAL and SIAC disputes involving the construction, internet advertising, the financial and steel industries. Also served as international arbitrator, as an expert for the World Bank Group with respect to arbitration-related civil procedure reform, while providing arbitration legal advice to a variety of other lawyers and clients in relation to ICSID, PCA, SIAC, DIAC, ad hoc and other international disputes.

Lazareff Le Bars – Of Counsel 

International Arbitration Of Counsel at Lazareff Le Bars, a law firm founded by the well-known French arbitrator Serge Lazareff. Served as co-lead international arbitration lawyer in a variety of disputes, such as the first reported investment treaty arbitration against Belarus and an UNCITRAL dispute with a United Nations agency. International arbitration lawyer in ICC, ICSID, CCJA and UNCITRAL international arbitrations in multilingual (primarily English, French, Spanish and Russian) disputes involving the energy, construction, consulting, pharmaceutical, aerospace and defence, banking and finance, shipping and transport, telecommunications, agricultural and steel industries. Served clients ranging from individual investors to major multinational corporations in disputes under a variety of common law and civil law legal regimes, including English law, French law, Moroccan law, Italian law, Swiss law, Equatorial Guinean law, German law, Malian law, Romanian law, Burkina Faso law, Byelorussian law, Belgian law, Swiss law, Illinois law, and private and public international law.

Dentons (formerly Salans) – Senior Associate

International arbitration lawyer at law firm ranked, at the time, as the European Law Firm of the Year and the French Law Firm of the Year, and which was consistently one of the top-ranked international arbitration practice groups in Russia and the CIS. Notable cases included Rumeli Telekom A.S. and Telsim Mobil Telekomunikasyon Hizmetleri A.S. v. Republic of Kazakhstan, ICSID Case No. ARB/05/16, Joseph Charles Lemire v. Ukraine, ICSID Case No. ARB/06/18 and The Rompetrol Group N.V. v. Romania, ICSID Case No. ARB/06/3. Counsel in ICSID and UNCITRAL investment treaty arbitrations, ICC, AFA, CICA and other commercial, construction and investment arbitrations. Representative work included claim against Poland involving the expropriation of intellectual property rights, ad hoc arbitration concerning an airplane lease agreement with an Angolan company, ICC arbitration against an African State concerning a customs agency, an ICC arbitration regarding the construction of a sulfuric acid plant in Turkey and an ICC arbitration concerning the breach of a shareholders’ agreement involving the automotive logistics industry. Served as counsel in disputes involving Kazakh law, Turkish law, Ukrainian law, Maltese law, English law, Iranian law, Polish law, Romanian law, French law, various U.S. laws, and private and public international law.

Shearman & Sterling – Associate

Arbitration lawyer at Shearman & Sterling’s Global Dispute Resolution Practice in Paris, classified by Chambers Global as “world-renowned” and the winner of the “Best International Arbitration Practice” in France for many years. Served as arbitration lawyer at the outset of the long-running Hulley Enterprises Ltd. (Cyprus) v. Russian Federation UNCITRAL arbitration, as well as UNCITRAL arbitrations involving the energy industry, ICC construction disputes, an ad hoc dispute concerning a Chinese search engine, an ICC dispute concerning a joint venture for the development of gas turbines, an LCIA shipping dispute, a mining dispute concerning New Caledonia, a pre-arbitral referee proceeding, and various other international disputes involving French law, English law, Algerian law, Russian law, Chinese law, Canadian law and Australian law.

United Nations International Criminal Tribunal for Rwanda – Legal Consultant

Legal Consultant for Prosecutor’s Office. Based in unit prosecuting military commanders allegedly responsible for Rwandan genocide (Military I Unit), focusing on the prosecution of the successful case against Colonel Bagosora and two other senior Rwandan army officers.

United Nations Department of Political Affairs – U.N. Consultant                                  

Drafted the Repertoire of the Practice of the Security Council, mandated by the General Assembly in 1952, which contains a constitutional and procedural guide to the proceedings of the Security Council.

American Peace Corps Côte d’Ivoire – UEM PCV

Worked in the rural Prefecture of M’bahiakro in the Ivory Coast for 27 months on behalf of the American Peace Corps, a U.S. State Department program. Implemented engineering projects in partnership with the U.S. Embassy, the French Embassy, UNAIDS and regional and municipal governments concerning urban renewal, waste management, infrastructure and irrigation systems, working in partnership with Ivorian public entities.


Lead counsel in successful ICC arbitration under English law on behalf of Canadian Claimant against Saudi Respondent manufacturer (amount in dispute USD 150 million)

Lead counsel in successful LCIA arbitration under Saudi law for Saudi Claimant against large South Korean construction company

Lead counsel in successful ICDR arbitration defending Canadian Respondent against American IT company (settled on favourable terms)

Lead counsel for Respondent in successful ICC construction dispute with South Korean General Contractor (all claims dismissed)

Lead counsel for Austrian company in two ICC arbitrations under Swiss law concerning construction projects in West Africa

Lead counsel in UNCITRAL arbitration administered by the PCA representing Eastern European State in road construction dispute

Lead counsel for Filipino Respondent in successful JAMS arbitration brought by American IT company regarding distribution agreement

Lead counsel in investment treaty arbitration on behalf of Russian investor against Northern European State

Lead counsel in investment treaty arbitration on behalf of Claimant Turkish investor against East Asian State

Lead counsel for Eastern European Respondent State in successful UNCITRAL arbitration in the electricity industry

Lead counsel in investment treaty arbitration against Belarus brought by Ukrainian foreign investor in the steel industry

Co-lead counsel in ICC arbitration on behalf of Turkish client against Chinese State-owned pipe manufacturer

Lead counsel in ad hoc international arbitration under OHADA law in the coffee and cocoa industry

Lead counsel in investment treaty arbitration against Swaziland brought by foreign investor in mining industry

Sole Arbitrator in ICC arbitration involving Asian and Middle Eastern Parties

Co-lead counsel in successful SIAC arbitration against large internet advertising company 

Sole Arbitrator in four DIAC disputes involving a real estate project in Dubai

Lead counsel to former British protectorate in public international law dispute

Co-counsel in an ICC dispute with related court measures on behalf of a Spanish company against two European businesses concerning an alternative investment fund

Counsel in ICC arbitration concerning the breach of a sales and purchase agreement between a Russian company and a Belgian agricultural equipment manufacturer

Litigation concerning the enforcement of an arbitral award in the United States on behalf of a French company

Co-counsel for arbitration-related interim measures sought on behalf of a Spanish company before French courts

Counsel with respect to an international arbitration against an Iraqi State entity 

Counsel for Respondents in successful ICC arbitration concerning the construction and development of a large shopping center in Romania by a joint venture composed of a Northern Irish company and a Lebanese company

Mediation followed by ICC proceedings involving the ownership and licensing terms of patents to chemical compounds between an American company and a French company

Counsel in French litigation concerning the annulment of an arbitration award rendered in North Africa

Counsel for Claimant in ICC proceedings concerning alleged breach of agency agreement between a Northern Irish company and a Swiss engineering company

Counsel for French contractor in Romanian Court of International Commercial Arbitration dispute concerning the construction of a luxury residential housing project in Romania by a major French contractor

Counsel for a Dutch company in successful ICSID proceedings brought against Romania concerning the oil-refining sector

ICC arbitration against African State on behalf of Claimant concerning the  modernization of its customs agency

Counsel for Danish client in ICC arbitration concerning the logistics industry 

Counsel in successful UNCITRAL investment treaty arbitration between Poland and a French company in the pharmaceutical industry

Counsel in successful ICSID proceedings on behalf of foreign investor against Tunisia concerning the acquisition of shares in Tunisia’s banking sector

Counsel in dispute concerning the sale and purchase of gas turbines being sold by a European company to India

AFA arbitration concerning a dispute over a financial services agreement

Dispute between European contractor and a Rwandese company concerning a construction project under Rwandese law

Counsel for successful American Claimant in ICSID arbitration brought against Ukraine concerning the media industry and the acquisition of broadcast licenses

Counsel for Respondent in ICC construction arbitration concerning a turnkey contract for the development of a sulfuric acid plant in Turkey

ICC proceedings on behalf of Claimant involving a dispute over a joint-venture to develop an advanced gas turbine between French, Swedish and British equipment manufacturers

ICC ADR proceedings between a French company and an African State involving a joint-venture in the telecommunications industry

Counsel in dispute between Swiss company and a United Nations agency concerning the provision of consulting services

ICC construction arbitration on behalf of European sub-contractor concerning the construction of oil pipeline

ICC proceedings on behalf of a French company concerning breach of contract by West African company

Counsel for international organisation intervening as amicus curiae in ICJ dispute concerning the extradition of a former African dictator from Senegal to Belgium

Counsel for Iranian oil and gas equipment distributor in an ICC arbitration against an American equipment manufacturer concerning a sales and purchase agreement

Co-counsel in investment treaty arbitration on behalf of Gibraltar-based Claimant against Russia involving the oil and gas sector

Counsel for Claimant in successful ICSID proceedings between Kazakhstan and Turkish investors involving the expropriation of a telecommunications company

UNCITRAL shipping dispute between an Algerian oil and gas producer and an American liquid natural gas regasification terminal

Counsel for successful Australian and Canadian Respondents in ICC dispute with Russian mining company involving a nickel mining concession in New Caledonia


  • English
  • French
  • Arabic (basic)
  • Spanish
  • Bambara (West African language)
  • Baoulé (West African language)



  • Attorney, New York
  • Attorney, Washington, D.C.
  • Avocat (Omis),Barreau de Paris


  • List of Arbitrators of USCIB (ICC National Committee for the United States)
  • ICC France (ICC National Committee for France)
  • Expatriate Subcommittee of USCIB (ICC National Committee for the United States)
  • ICDR Young & International Arbitration Group
  • List of Arbitrators (DIAC)
  • Legal 500
  • Leader’s League (Décideurs)
  • Kluwer Author
  • Swiss Arbitration Association (ASA)
  • Getting the Deal Through Author
  • International Bar Association
  • AFIA (Australian Forum for International Arbitration)
  • Advisor to Young ICCA
  • Editor of Vindobona Journal of International Commercial Law


Columbia University School of Law, J.D. (2002)

Dorsey & Whitney Prize

Stone Scholar

Tony Patiño Fellowship for Outstanding Character

The Sorbonne (Paris I – Panthéon-Sorbonne), Maîtrise en Droit (2004)

French J.D.-equivalent awarded with honours

Harvard University, B.A. (1997)

Degree awarded with high honors (magna cum laude)

Dean’s list all semesters

Magna cum laude thesis on the history of empiricism in pharmacology


University of Paris X (Nanterre School of Law), Lecturer on Anglo-American Business Law

University of Paris II (Panthéon-Assas), Lecturer on International Arbitration

Webinars on issues such as the use of international arbitration to resolve intellectual property disputes for Oxford-based entity

Back to index

Legal Developments in Switzerland

Legal Developments and updates from the leading lawyers in each jurisdiction. To contribute, send an email request to
  • Ordinance on Integrity and Transparency in the Therapeutic Products Sector has been adopted

    Click here for more information.
  • Bär & Karrer Advises B3i in its Current Equity Funding Round

    Industry-led InsurTech B3i Services AG successfully raised additional funds from current shareholders and new investors to further develop and grow its blockchain-based insurance transaction platform. B3i was founded in October 2016 as an insurance industry consortium which then formed B3i Services AG as an independent company. The shareholder group includes some of the world's largest insurers and reinsurers from across Europe, the Americas, and Asia. B3i intends to further expand its shareholder base over the next several months.
  • Bär & Karrer Continues to Grow Finance and Sports Practice with Two New Partners

    Bär & Karrer is pleased to announce that it further strengthens its Financing and Sports practices with new partners Lukas Roesler and Dr. Jan Kleiner, both of whom have worked with the firm previously.
  • Bär & Karrer Advises Novartis and Alcon on the Spin-off of Alcon

    Today, Novartis AG completed the spin-off of the Alcon eye care devices business, and Alcon Inc. debuted as independent publicly traded company. The Alcon shares were successfully listed on the SIX Swiss Exchange Ltd. and the New York Stock Exchange. They are also included in the Swiss Market Index (SMI), which comprises the 20 largest Swiss listed stocks.
  • Bär & Karrer Advises Primeo Energie and CSA Energie-Infrastructure Schweiz in Aquisition from Elét

    Primeo Energie, EOS Holding SA (EOS) and Électricité de France (EDF) have entered into a share purchase agreement relating to the purchase by Primeo Energie and EOS of the 25% interest held by EDF in Alpiq Holding SA. The purchase by Primeo Eergie and EOS will be financed through mandatory exchangeable loan agreements made by CSA Energie-Infrastruktur Schweiz (CSA) as lender, the biggest investment pool for Swiss energy infrastructure with 135 Swiss pension funds acting as investors. At maturity the mandatory exchangeable loan agreements will be converted into shares in Alpiq. Primeo Energie and EOS thereby pave the way for a Swiss shareholder structure of Alpiq.
  • Bär & Karrer Awarded Most Innovative Swiss Law Firm of the Year at the IFLR Europe Awards

    Bär & Karrer was awarded „Most innovative law firm of the year - Switzerland", the national award for Switzerland given in the IFLR European Awards. The most innovative law firm of the year award recognizes Bär & Karrer as the Swiss law firm with the best track record in 2018 giving advice on the most innovative cross-border deals covering all award practice areas. It is already the third prize of this kind in period of six years awarded to Bär & Karrer.
  • Bär & Karrer Advises DSV on Public Exchange Offer for Panalpina

    On 1 April 2019, DSV A/S, Hedehusene, Denmark and Panalpina Welttransport (Holding) AG, Zurich, Switzerland, have entered into an agreement on the terms and conditions of a combination by way of a public exchange offer by DSV for all publicly held registered shares of Panalpina for approximately CHF 4.6 billion. The board of directors of Panalpina has resolved to support the public exchange offer by DSV and to recommend the acceptance of DSV's public exchange offer to its shareholders.
  • Bär & Karrer Advises Lonza on the Entering into a Strategic Joint Venture with Chr. Hansen for Deve

    On 2 April 2019, Lonza, a leading pharma contract manufacturing company, and Chr. Hansen, a leading global bioscience company, announced that they have signed an agreement to establish a 50/50 joint venture to pioneer the live biotherapeutic products (LBPs) industry and position themselves as the leading contract development and manufacturing partner (CDMO) for biotech and pharma customers. The joint venture brings together best-in-class, complementary capabilities and will be the first CDMO globally to provide a full supply chain that offers manufacturing of bacteria strains for therapeutic use. The joint venture will be a 50/50 controlled legal entity that will operate from its headquarters in Basel (CH) and have production facilities in Denmark and Switzerland. A phased investment of approximately EUR 90 million will be deployed over three years to build cGMP-compliant pharma production capabilities. The joint venture will upgrade existing facilities in Hørsholm (DK) and equip new facilities in Basel (CH) to serve pre-clinical to phase II projects. Further facilities for phase III and commercial manufacturing will be developed as the pipeline matures. The joint venture is expected to be largely self-funding after the production set-up has been established.
  • Bär & Karrer Advises Computacenter in the Acquisition of PathWorks

    Computacenter Group, a leading European IT service provider listed on the London Stock Exchange, acquired PathWorks, a well-established hardware reseller in the Swiss market.
  • Bär & Karrer Advises Addtech in the Acquisition of a Majority in Omni Ray

    Addtech Group, a leading Swedish publicly listed technology trading group, acquired a majority stake in Omni Ray AG, a well-established Swiss trading company and service provider for automation solutions, mainly focused on industrial applications, infrastructure, transportation and medical industry. By this transaction, Addtech aims at strengthening its position in the European automation market.