Martínez de Hoz & Rueda is especially active in cross-border mandates spanning the oil-and-gas, mining, construction and infrastructure sectors, as well as environmentally sensitive and politically charged disputes. At the forefront is name partner José Martínez De Hoz, who is renowned for his role as counsel and arbitrator in complex ICSID, ICC, and other international proceedings - particularly those linked to the energy sector. He co-leads the practice with Francisco Amallo, a key name for commercial and investment arbitration, as well as cross-border litigation. Juan Cruz Azzarri adds further depth on domestic litigation involving environmental and regulatory challenges. At senior associate level, Milagros Sanguinetti handles litigation and arbitration across commercial, energy and private client law; while the Montevideo-based Pablo Pereira Brause provides additional depth to the practice group’s international disputes offering.
Legal 500 Editorial commentary
Testimonials
Collated independently by Legal 500 research team.
- Martínez de Hoz & Rueda stands out as our go-to firm in Argentina for complex international arbitration. What distinguishes the practice is the rare combination of deep technical expertise and genuine commercial judgment; they don't just provide a legal analysis, they think alongside you as counsel about strategy, risk, and the best path to a commercial outcome. The team's technical quality is, in my experience, on par with the leading international arbitration practices. Their written submissions are rigorous, well-structured, and persuasive, and their command of both Argentine law and international arbitration practice makes them particularly effective in cross-border matters where the two systems intersect. They are equally comfortable acting under ICC, ICSID, UNCITRAL, and ad hoc rules. José A. Martínez de Hoz and Francisco A. Amallo lead the matters I have been involved in, and both are outstanding. José brings exceptional strategic vision and the kind of seniority and judgment that gives clients real confidence in high-stakes situations. Francisco is a first-class arbitration lawyer — sharp, technically excellent, and unfailingly responsive — and he runs cases with a level of rigor and attention to detail that I have rarely seen matched. Together they make a formidable pairing. What sets the team apart in day-to-day work is their responsiveness and availability. Despite handling high-profile matters, the partners are personally engaged, accessible at short notice, and consistently meet demanding deadlines without compromising quality. There is no sense of being handed off to junior associates — senior lawyers stay close to the matter from start to finish, which is not always the case with firms of comparable standing. Strategically, they are commercially minded rather than purely litigious. They understand that arbitration is a means to an end, and they tailor their approach — including when to push hard, when to settle, and how to position the case — to the client's broader business objectives. This combination of technical depth and commercial pragmatism makes them, in my view, the strongest dispute resolution team in Argentina and a firm I would recommend without hesitation to any client facing a significant dispute in the region.
- José A. Martínez de Hoz is a top-tier international arbitration lawyer among the strongest practitioners I have worked with in the field, anywhere. He combines deep experience with sharp intellect and real creativity in how he approaches complex disputes. He sees angles and strategic options that others miss and translates them into a clear, executable plan. He is also exceptionally responsive and personally engaged, which is rare at his level of seniority. Clients get his direct attention, his judgment, and his commitment — qualities that make a material difference in high-stakes arbitration. Francisco A. Amallo is an outstanding arbitration partner who complements José perfectly. He is technically excellent, meticulous, and unfailingly responsive, and he runs cases with a level of rigor and attention to detail that consistently stands out. He is the kind of lawyer you want managing the day-to-day of a complex arbitration: sharp, reliable, and entirely on top of every aspect of the matter.
Key clients
Altria Group
CAPEX
Chevron Argentina
Chevron Uruguay
Compañía de Hidrocarburo No Convencional (CHNC)
Exxon Mobil
Gramercy
Sebastian Popper
Neoen
Pan American Energy
Petroquímica Comodoro Rivadavia
Pluspetrol
Work highlights
Represented Chevron in Uruguay in its defense against an injunction request filed by several NGOs before the Civil Courts of the city of Montevideo; the action seeks to stay all work in relation to offshore exploration and exploitation licenses that Chevron and other oil & gas companies hold in Uruguay.
Acting as arbitrator appointed by Concesionaria Angostura Siguas, a construction services company, in an investment dispute against Peru in relation to a concession contract; the tribunal issued Procedural Order No. 1 on June 13, 2025.
Represented Naviera Lojda and Barranca Fighiera, two hydraulic frac sand producers, in an UNCITRAL arbitration administered by the Permanent Court of Arbitration and initiated by Emerald Energy and Emerald Resources, in relation to a joint venture agreement. The final award was issued in February 2025 and dismissed all of claimants’ claims - a huge success to our clients.
Lawyers
Hall of Fame
The lawyers at the very top of the profession, widely known and respected by peers and clients for their longstanding involvement in market-leading work.
Leading partners
The strongest partners in their field, leading on market-leading deals and endorsed by peers and clients alike.
Francisco Amallo
Practice head
José Martínez De Hoz; Francisco Amallo
Other key lawyers
Juan Cruz Azzarri; Milagros Sanguinetti; Pablo Pereira Brause