Ari D. MacKinnon’s practice focuses on disputes matters in Latin America with a particular emphasis on international arbitration and corruption issues. 

Ari has successfully represented a number of major Latin American oil and gas, energy, infrastructure, and pulp and paper companies as well as other clients in disputes in the region. He speaks regularly in Latin America on topics related to arbitration and crisis management. Ari has experience conducting arbitration and corruption-related disputes matters in both English and Spanish. 

Ari joined the firm in 2009 and became a partner in 2015.

Notable Experience

International Arbitration

  • An international oil and gas company in the defense of a Spanish-language, Peruvian law-governed ICC arbitration relating to liabilities allegedly arising from the wrongful termination of an oil concession agreement.

  • Pluspetrol Peru Corporation S.A., Pluspetrol Block 56 S.A., Tecpetrol Block 56 S.A.C., and Sonatrach Peru Corporation S.A. in a complex ICC arbitration derived from an ICSID arbitration against the Peruvian State related to claims against a Peruvian buyer of gas, successfully obtaining a final award and securing payment of over $133 million arising from additional amounts owed on invoices due for hydrocarbons exports.

  • Six Peruvian companies in two ICC arbitrations, governed by New York law and consolidated into one arbitration proceeding, claiming additional payments for payments due for hydrocarbon exports.

  • A Peruvian oil and gas company in the successful prosecution of a Spanish-language, Peruvian law-governed IACAC arbitration relating to alleged breaches of an oil concession agreement, which included claims and arguments relating to contractual, regulatory, environmental, and pipeline management issues.

  • Latin American glass manufacturer in an ICC arbitration and related civil litigation concerning the interpretation of an exclusive sales agreement.

  • Latin American oil and gas company in an ICC arbitration related to alleged breaches of representations and warranties regarding environmental issues in an asset sale agreement.

  • A European retailer in a merger-related ICC arbitration seated in São Paulo, and governed by Brazilian law.

  • Casino operator in New York-law governed, JAMS-arbitration relating to calculation of percentage rent owed under lease agreement. 

  • Western Digital’s SanDisk subsidiary in the successful pursuit and settlement of three separate ICC arbitrations against Toshiba arising out of Toshiba’s efforts to sell its stake in the parties’ multibillion-dollar NAND flash memory joint ventures without SanDisk’s consent, and related injunction proceedings in California state court.

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Enforcement and Investigations

  • An international financial institution in parallel investigations being conducted by, among others, the UK Financial Conduct Authority, the U.S. Department of Justice, and the U.S. Commodity Futures Trading Commission, relating to the FX market; also counsel to the same institution in regulatory investigations in the U.S. related to the setting of the ISDAFIX.

  • FCPA and corporate governance advice to a Mexican construction company in connection with an investigation by the CNBV and potential investigation by the SEC.

  • Advice concerning the design and enhancement of anti-corruption policies and internal controls for a Latin American pulp and paper company and a petroleum company.

  • Advice concerning the enhancement of compliance policies and procedures for international financial institution in connection with regulatory investigations of alleged attempted manipulation.

  • Alpha Natural Resources, Massey Energy Company, and Performance Coal Company in reaching a comprehensive settlement with the U.S. Department of Justice resolving potential corporate, criminal, and civil liability related to the Upper Big Branch Mine tragedy, in which 29 miners died.

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Other Litigation

  • YPF, S.A. and certain of its former subsidiaries in an action brought by the Maxus Liquidating Trust in the U.S. Bankruptcy Court for the District of Delaware to recover damages relating to allegedly fraudulent transfers and alleged alter ego liability arising out of the alleged pollution of the Passaic River in New Jersey.

  • BNP Paribas in clawback actions brought by the Trustee of the Madoff Estate in the U.S. Bankruptcy Court for the Southern District of New York in connection with the Bernie Madoff Ponzi scheme.

  • Alpha Natural Resources and certain of its directors and officers in a successful motion to dismiss a federal securities law class action brought under Section 11 of the Securities Act.

  • American Express Co. in successfully securing dismissal of shareholder derivative litigation brought in New York State court.

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Selected Activities

  • Member, Board of Directors and Program Committee, New York International Arbitration Center
  • Member, Chartered Institute of Arbitrators
  • Included on Arbitrator Roster, Arbitration Centre of the Lima Chamber of Commerce
  • Member, New York City Bar Association Council on International Affairs
  • Member, International Arbitration Club of New York
  • Member, Association of International Petroleum Negotiators


U.S. Supreme Court Rules That Judges, Not Arbitrators, Decide If A Dispute Is Arbitrable When Multiple Agreements Conflict On The Question,” Cleary Gottlieb Alert Memorandum, May 28, 2024

International Bar Association Publishes Revisions to Guidelines on Conflicts of Interest in International Arbitration,” Cleary Gottlieb Alert Memorandum, March 8, 2024


Five International Arbitration Trends and Topics for 2024,” Cleary Gottlieb Alert Memorandum, January 4, 2024

“Arbitraje y la Constitución Argentina,” Arbitragem e ConstituiçaoThomson Reuters’ Revista Dos Tribunais, November 2, 2023

Investment Treaty Arbitration: Ecuador,” Global Arbitration Review, October 2, 2023

“The Lithium Triangle: Challenges and Opportunities for Latin America,” Cleary Gottlieb Alert Memorandum, September 25, 2023

U.S. Supreme Court Authorizes Foreign Plaintiffs To Use Domestic RICO Statute In Aid Of Enforcement Of Arbitral Awards In The United States,” Cleary Gottlieb Alert Memorandum, July 3, 2023  

U.S. Supreme Court Rules That An Appeal Of An Order Denying A Motion To Compel Arbitration Automatically Stays District Court Proceedings,” Cleary Gottlieb Alert Memorandum, June 29, 2023

Investment Treaty Arbitration,” Corporate Disputes Magazine, June 8, 2023

Commercial Arbitration: Brazil,” Global Arbitration Review, March 28, 2023

Strategies for Effective Brief Writing in International Arbitration,” Arbanza Investment Arbitration Guide, March 16, 2023

Five International Arbitration Trends And Topics For 2023,” Cleary Gottlieb Alert Memorandum, January 30, 2023

ESG-Related Disputes in Latin America: The Evolution of the Litigation and Arbitration Landscape,” Latin Lawyer, December 16, 2022

The Rise of ESG Disputes and the Role of Arbitration in Resolving Them,” Financier Worldwide, December 6, 2022

Arbitration of Corruption Issues in Latin American Disputes,” Latin Lawyer and Global Arbitration Review, September 15, 2022

ZF Automotive v. Luxshare – Opinion of the Supreme Court of the United States,” Jus Mundi, July 25, 2022

2nd Circuit Ruling Offers Clarity for Annulled Arbitral Awards,” Law360, July 20, 2022

Amended ICSID Arbitration Rules Enter Into Force,” Cleary Gottlieb Alert Memorandum, July 15, 2022

U.S. Supreme Court’s Decision on the Applicability of Section 1782 Discovery Likely to Have Practical Impact on Arbitration in Latin America,” Cleary Gottlieb Alert Memo, July 6, 2022

U.S. Supreme Court Denies Applicability of Section 1782 Discovery Statute With Respect to Private Commercial and Treaty Arbitrations,” Cleary Gottlieb Alert Memo, June 15, 2022

The New Supplemental Arrangement Concerning Enforcement of Arbitral Awards between Mainland China and Hong Kong,” Cleary Gottlieb Alert Memo, August 25, 2021“Ecuador Signs the ICSID Convention, What That Means for Ecuador and the Rest of South America,” Cleary Gottlieb Alert Memo, August 9, 2021 

Second Circuit Reinforces Its Approach To Section 1782 While U.S. Supreme Court Case On Application Of Section 1782 To Private International Arbitration Remains Pending,” Cleary Gottlieb Alert Memo, July 19, 2021

The Scope of Immunity for International Organizations Comes Under Scrutiny Again, Two Years After the U.S. Supreme Court’s Decision in Jam v. International Finance Corporation,” Cleary Gottlieb Alert Memo, March 1, 2021 

2020 Revision of the IBA Rules on the Taking of Evidence in International Arbitration,” Cleary Gottlieb Alert Memo, February 17, 2021 

The London Court of International Arbitration Releases Updated Arbitration Rules, Emphasizing Efficiency,” Cleary Gottlieb Alert Memo, October 26, 2020 

Circuit Split Intensifies Over Use of 28 U.S.C. § 1782 to Obtain Discovery for Use in Private International Arbitration,” Cleary Gottlieb Alert Memo, July 13, 2020 

Supreme Court Holds That New York Convention Does Not Preclude Non-Signatories From Invoking State Law Principles To Compel Arbitration,” Cleary Gottlieb Alert Memo, June 3, 2020 

Most EU Member States Agree to Terminate Their Intra-EU Bilateral Investment Treaties,” Cleary Gottlieb Alert Memo, May 7, 2020

U.S. District Court Denies Section 1782 Discovery for Use in DIS Arbitration, Highlighting Deepening Circuit Split on Statute’s Applicability to Private Commercial Arbitrations,” Cleary Gottlieb Alert Memo, April 3, 2020

Second Circuit Overturns Arbitration Award Against Non-Signatory Parent Company,” Cleary Gottlieb Alert Memo, April 3, 2020

COVID-19 and the Tolling Of Statutes of Limitations: Impact on Arbitrations Seated in New York,” Cleary Gottlieb Alert Memo, March 25, 2020

3 NY Contract Law Concepts In The Context Of Coronavirus,” Law360, March 4, 2020

Potential End of Suspension of Title III of the Helms-Burton Act: Authorization of Claims Under U.S. Law for “Trafficking” in Certain Cuban Properties,” Cleary Gottlieb Alert Memo, February 26, 2019

Supreme Court Confirms Arbitrators Decide Threshold Issues,” Cleary Gottlieb Alert Memo, January 9, 2019

40 Under 40 International Arbitration (2018), July 12, 2018

“A Reassuring 2nd Circ. Approach To Annulled Awards,” Law360, July 28, 2017

Drafting International Arbitration Clauses,” THĒMIS-Revista de Derecho, March 26, 2017

Second Circuit Confirms That an Arbitral Award That Has Been Nullified at the Seat of the Arbitration Should Rarely Be Enforced,” July 27, 2017

Second Circuit Rules That FSIA Provides Sole Basis for Jurisdiction Over Foreign Sovereigns in Actions to Enforce ICSID Awards,” July 17, 2017