Cleary Gottlieb Steen & Hamilton continues to secure victories in complex commercial and investment treaty arbitrations. The firm boasts a prominent group of lawyers who are proficient in Spanish and Portuguese, allowing them to handle a range of arbitrations. The team is capable of acting as counsel to both investors and states in investment treaty proceedings in matters relating to energy, oil and gas. Ari MacKinnon, co-head of the firm's international arbitration practice, has successfully represented Pluspetrol Peru Corporation and others against a Peruvian buyer of gas in winning an award valued at over $130m in an ICC arbitration. Jeffrey Rosenthal focuses on general commercial arbitrations and has represented both foreign and domestic entities before a range of arbitral bodies. Carmine Boccuzzi has successfully represented the Republic of Argentina in multiple lawsuits across various US jurisdictions, while Katie Gonzalez, who was raised to the partnership in October 2025, has experience counselling both sovereign and private clients. Elisa Zavala is a key associate in the team. All named lawyers are based in New York.
Legal 500 Editorial commentary
Accolades
Client satisfaction: Lawyer & team quality
Client satisfaction: Billing & efficiency
Client satisfaction: Sector knowledge
Testimonials
Collated independently by Legal 500 research team.
‘The practice is distinguished by its efficiency and quality of service. The team is comprised of highly qualified attorneys with extensive experience in various areas of law. Their ability to work collaboratively and their commitment to excellence are some of the strengths that set them apart from other firms.’
‘Attorneys like Katie Gonzalez and Jeffrey Rosenthal are known for their dedication and exceptional skills. Each brings a unique combination of experience and knowledge that strengthens the team and ensures positive results for clients.’
Key clients
- Pluspetrol Resources Corporation
- The Republic of Argentina
Work highlights
Counsel to Pluspetrol Resources Corporation, S.A. (“PRC”) in a Spanish-language ICC arbitration concerning the allegedly wrongful termination of a license contract for the exploration and exploitation of hydrocarbons at Block 8 in Peru.
Lawyers
Leading partners
The strongest partners in their field, leading on market-leading deals and endorsed by peers and clients alike.
Next Generation Partners
Junior partners with significant recognition from clients and peers in the market and key roles on multiple matters.
Leading associates
Leading associates with regular involvement in their team's key work, and recognition from peers or clients as being ones to watch.
Katie Gonzalez
Practice head
Ari MacKinnon
Other key lawyers
Jeffrey Rosenthal; Carmine Boccuzzi; Katie Gonzalez; Elisa Zavala