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Sarah Busca Bonvin
Partner

Sarah Busca Bonvin

Attorney at Law | Co-Head of Tax Practice Group | Certified Tax Expert

Languages
  • French
  • English
  • Italian
Social media

Sarah Busca Bonvin is a lawyer specializing in tax law for both legal entities and individuals. In collaboration with Andrio Orler, she is responsible for CMS' tax department in Geneva, which she joined in 2017.

Certified as tax expert, she worked for 17 years as Director of Tax Affairs, particularly handling tax rulings, before being appointed Deputy Director General of the Geneva Tax Administration in 2010. Her roles within the Geneva Tax Administration allowed her to gain extensive experience and expertise in various areas of taxation.

Sarah Busca Bonvin regularly teaches in the LL.M. Tax program at the University of Geneva about the topics of corporate taxation and transfer pricing, as well as in the training program for tax experts (corporate taxation).

Awards & Recognitions
01
  • Quote
    We had a very positive experience working with Sarah Busca-Bonvin. We trust her as a lawyer; she is very responsive and provides solid advice.
    Chambers and Partners, Europe Guide Tax, Switzerland 2026

Publications

  • "La vente immobilière en viager: aspects de droit de droit civil et principales conséquences fiscales", in Not@lex 1/20: la revue de droit privé et fiscal du patrimoine

Memberships & Roles

  • Member of the Geneva Section of the Tax Expert Association (OREF)
  • Member of the IFA (International Fiscal Association)

Awards & Rankings

  • Chambers and Partners | Europe Guide | Recognized in Tax Law, Switzerland 2026
  • Chambers and Partners | Global Guide | Recognized in Tax Law, Switzerland 2026
  • Best Lawyers 2026 | Recognized in The Best Lawyers in Switzerland 2026 for Tax Law

Lectures list

  • Conference CMS Talks – "Fondation : évolutions récentes et en jeux pratiques", November 2025
  • OREF Seminar - ‘From investor to investment’ - Taxation of wealth in the case of indirect ownership, October 2023
  • UNIL - ‘The arm's length principle in Swiss corporate tax law - Benefit attribution: triangle theory versus direct beneficiary theory, March 2023
  • AGDA Seminar, FER Geneva - Classical foundations under Swiss private law, tax considerations, March 2023
  • Introduction of the trust in Swiss law: civil and tax law perspectives, Société genevoise de droit et de législation (SGDL), June 2022
  • Wealth Planning Perspectives - Planification patrimoniale franco-suisse, Banque Lombard Odier & Cie SA, March 2022
  • Actualités en matière d'imposition à la source, L'imposition à la source des travailleurs, ISIS, November 2020
  • Journée de droit fiscal, Exposé de jurisprudence, OREF/University of Geneva, February 2020
  • La fiscalité de la philanthropie, L'exonération des entités poursuivant un but d'utilité publique ou de service public, ISIS, November 2019
  • Accompagner la clientèle francophone dans la mobilité internationale, LODH, November 2019
    Post BEPS intellectual property taxation in Europe, CMS Tax Conference, Paris, January 31st 2019
  • CMS Talks | 5 perspectives sur le trust (fiscal aspects), Hôtel Mandarin Oriental, Geneva, November 20th 2018
  • Aperçu de la mise en oeuvre de la RFFA par les cantons, International Fiscal Association (IFA) Suisse, November 2018
  • Spontaneous Exchange of rulings – The post-BEPS World, University of Lausanne, October 2016
  • Réforme de l’imposition des entreprises III, Expertsuisse, Lausanne, September 2016
  • Actualités fiscales organisé par l’Ordre romand des experts fiscaux (OREF), l’Ordre genevois de la Chambre fiduciaire (OGCF) et Fiduciaire suisse, Genève, March 2016
  • Le step-up, International Fiscal Association, Berne, November 2015
  • Corporate tax reform III – The proposed measures from a cantonal perspective, Steuerkonferenz, Hochschule, Lucerne

Education

  • 2006 – Certified tax expert exam
  • 1999 – Bar exam
  • 1994 – Law degree, University of Geneva (Switzerland)
Practice Areas

Insights by Sarah

Foundations under Swiss law: an overview

10 Oct 2025 7 min read

CMS Switzerland recommended among the best law firms in Switzerland by The Legal 500 EMEA 2023

12 Apr 2023 2 min read

CMS Switzerland recognised by The Legal 500

11 Apr 2022 2 min read

CMS Switzerland ranked by The Legal 500

14 Apr 2021 1 min read
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