
O'Farrell is best known for its outstanding track record in tax litigation, where it has secured favourable outcomes for corporate and individual taxpayers in high-stakes, precedent-setting tax disputes in the municipal, provincial and national courts. In addition to the strength of its contentious practice, the firm also covers tax-free organisations, social security tax, holding company taxation, stamp taxation and energy taxation. The practice is led by exceptional tax practitioner Miguel A.M. Tesón, who is called on by blue-chip international and domestic clients for advice on cross-border taxation matters, transfer pricing, tax planning, federal tax law and local taxation. A trio of three partners provide further senior expertise. The vastly experienced Guillermo Lalanne is a reference on constitutional and national tax law, and advises on complex litigation; Valeria Estathio is a go-to name on federal and international tax law matters, with double taxation conventions, inbound investments, and cross-border reorganisations particularly strong areas; and tax disputes lawyer María Celina Valls handles transfer pricing disputes in agribusiness and leads on inflation adjustment taxation issues.
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- Profil
Kernmandanten
- Pampa Energía/Petrobras
- Naturgy Argentina
- Droguería del Sud
- Ford Argentina
- Importadora y Exportadora de la Patagonia
- Grupo Telefónica Argentina
- Biogenesis Bago
- Transener
- ZTE
- SACDE
Highlight-Mandate
- Successfully defended Hidroeléctrica Diamante against a claim from the Argentine Federal Tax Authority challenging the depreciation of a concession permit on the grounds that the company had not paid any consideration for said concession.
- Submitted a claim on behalf of Telefónica de Argentina challenging the constitutionality of prohibiting inflation adjustment provisions to asset depreciation for income tax purposes.
- Obtained a favourable decision for SO Energy from the Federal Supreme Court in a stamp tax claim pursued by the Province of Salta.
Anwält*innen
Hall of fame
Die Anwält*innen an der Spitze ihres Berufsstands, die aufgrund ihres langjährigen Engagements in marktführender Arbeit von Wettbewerbern und Mandanten gleichermaßen geschätzt und anerkannt werden.

Führende Partner*innen
Die stärksten Partner*innen ihres Praxisbereichs, die eine führende Rolle in signifikanten Mandaten einnehmen und weitreichende Anerkennung unter Wettbewerbern und Mandanten genießen.
Valeria Estathio

Guillermo Lalanne
Partner*innen der nächsten Generation
Juniorpartner*innen, die im Markt von Mandanten und Wettbewerbern anerkannt werden und in einigen Mandaten eine Schlüsselrolle einnehmen.
Praxisleitung
Miguel A.M. Tesón