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Marc KLEYR

Marc KLEYR

Senior Partner

Expertise

Marc KLEYR has been a co-founder and Senior Partner of the firm for 30 years, since its inception.

Senior Partner in the firm’s Corporate and Finance Litigation department, he is highly regarded in the market for his experience in commercial and corporate litigation, with a special focus on shareholders’ litigation, finance litigation, insolvency-related litigation and audit negligence claims.

Marc has a unique expertise in multi-jurisdictional and cross-border cases. Over the last 20 years, he has been involved in all major high-profile corporate finance and insolvency-related litigation cases in Luxembourg.

“Marc Kleyr is a strategic and solid advocate.”

Legal500 EMEA, 2026

“Marc Kleyr combines deep experience with a bold, confident approach that inspires trust in complex litigation matters.”

Chambers & Partners Europe, 2026

+352 227 330-730

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EDUCATION

Master's degree in private law, University of Strasbourg, 1990

DEUG, Center for French Legal Studies, University of Saarbrücken, 1988

Philosophy and Foreign Languages, University of Saarbrücken, 1986

LANGUAGES

English, French, German, Luxembourgish

MEMBERSHIPS

Luxembourg Bar, admitted in 1991

International Association of Lawyers (UIA)

International Association of Restructuring, Insolvency & Bankruptcy Professionals (INSOL)

R3 – Association of Business Recovery Professionals

RECOGNITIONS

Recognitions

Events

  • KLEYR GRASSO at the IBA Annual Conference 2026 in Copenhagen
    Copenhagen, Denmark

    KLEYR GRASSO at the IBA Annual Conference 2026 in Copenhagen

    We are delighted to announce that KLEYR GRASSO will be attending the IBA Annual Conference 2026, taking place from 4 to 9 October 2026 in Copenhagen, Denmark. Recognised as the world's leading networking…

  • IBA Annual Litigation Forum – The world has lost its compass: we need to talk about litigators!
    MADRID

    IBA Annual Litigation Forum – The world has lost its compass: we need to talk about litigators!

    We are pleased to attend the IBA Annual Litigation Forum in Madrid, a key global event for the international litigation community. Partners Marc KLEYR and Emilie Waty will represent the firm and…

Related News

Read the latest related news from our experts or explore our full insights which cover new laws, bills, and ongoing developments.

  • The Cour de Cassation recognises the right of a minority shareholder to join proceedings as a civil party before the investigating judge in respect of the losses suffered by the company

    The Cour de Cassation has just delivered a completely unprecedented decision. On 4 June 2026, it recognised the admissibility of a minority shareholder joining proceedings as a civil party before the investigating…

  • A court-appointed provisional administrator cannot evade the rules and legal obligations applicable to companies

    New case law Corporate and Finance litigation

  • Consistent excellence and client trust reaffirmed in The Legal 500 EMEA 2026 edition
    • EN

    Consistent excellence and client trust reaffirmed in The Legal 500 EMEA 2026 edition

    KLEYR GRASSO is pleased to announce its continued recognition in The Legal 500 Europe, Middle East & Africa 2026, reaffirming the firm’s consistent excellence and the trust placed in it by clients…

  • KLEYR GRASSO reaffirmed as a Leading Law Firm in Luxembourg by Chambers Europe 2026
    • EN

    KLEYR GRASSO reaffirmed as a Leading Law Firm in Luxembourg by Chambers Europe 2026

    KLEYR GRASSO is proud to announce its continued recognition in the Chambers Europe Guide 2026, reaffirming the firm’s position among the leading law firms in Luxembourg.

  • KLEYR GRASSO contributes to the Chambers Global Practice Guide: Litigation 2026

    KLEYR GRASSO contributes to the Chambers Global Practice Guide: Litigation 2026

    Donata GRASSO and Emilie WATY, Partners in our Corporate & Finance Litigation department, are pleased to share the Luxembourg chapter of the Chambers & Partners 2026 Litigation Global Practice Guide. This jurisdiction-specific…

  • The usufructuary of shares in a public limited company (société anonyme) is not allowed to request the convening of a general meeting

    Authored by Donata GRASSO, Partner and Ella SCHONCKERT, Counsel In a landmark decision rendered on 2 December 2025, the 4th Chamber of the Luxembourg Court of Appeal held for the first time…

  • KLEYR GRASSO contributes to the Chambers and Partners International Arbitration 2025 Global Practice Guide
    • EN

    KLEYR GRASSO contributes to the Chambers and Partners International Arbitration 2025 Global Practice Guide

    We are proud to announce that KLEYR GRASSO is the exclusive contributor for Luxembourg in the Chambers and Partners International Arbitration 2025 Global Practice Guide. In this edition, our experts Emilie Waty…

  • KLEYR GRASSO strengthens key practice areas with the addition of eight new lawyers
    • EN

    KLEYR GRASSO strengthens key practice areas with the addition of eight new lawyers

    As part of our continued growth and strategic development, and in response to the increasing demand from our clients, we are pleased to announce the arrival of eight new lawyers to our…

  • KLEYR GRASSO Recognized with Top-Tier Ranking in Legal500 EMEA 2025 for Luxembourg!
    • EN

    KLEYR GRASSO Recognized with Top-Tier Ranking in Legal500 EMEA 2025 for Luxembourg!

    KLEYR GRASSO has once again secured a Top-Tier ranking in the prestigious Legal500 EMEA 2025 for Luxembourg. This recognition underscores our firm’s dedication to excellence, client success, and legal expertise across our…

  • “La mise en état devant les juridictions luxembourgeoises : regards croisés de praticiens et pistes d’évolution”, Revue des Procédures, Legitech, March 2025

    Revue des procédures 2026/1 n° 10 _ Les récentes réformes du Nouveau Code de procédure civile : bilan et perspectives Actes du colloque du 21 mars 2025 Par S. Alves, Donata Grasso,…

    • EN

    Chambers Europe 2025 – A Renewed Recognition of Our Excellence

    KLEYR GRASSO is proud to be recognized once again by Chambers and Partners in its 2025 Europe guide for its exceptional legal expertise. Our ongoing position among the top law firms in…

    • EN

    KLEYR GRASSO announces major promotions effective January 1, 2024

    KLEYR GRASSO is pleased to announce the promotion of ten outstanding individuals within its ranks. Effective January 1, 2024, the promotions mark a significant step in the firm's growth strategy and commitment…

  • The new law on business continuity and modernising bankruptcy law entered into force on 1 November 2023

    The law of 7 August 2023 on business continuity and modernising bankruptcy law (hereafter the “Law”) which implements the Directive (EU) 2019/1023 of 20 June 2019 on preventive restructuring frameworks, on discharge…

    • EN

    Arbitration Reform – Highlights of the Law of 19 April 2023

    The law of 19 April 2023 amending the second part, book III, heading I of the New Code of civil procedure reforming arbitration enters into force this Tuesday, 25 April 2023 (hereafter…

  • Shareholder disputes – abuse of equality

    In a recent decision dated 21 December 2022, no. 183/22-VII-CIV, the 7th Chamber of the Court of Appeal has confirmed that the abuse of equality (abus d’égalité), consisting for a holder of…

  • A court action for dissolution of a company for just cause is an action reserved to the company’s shareholders

    By a decision rendered on 2 March 2022, the 7th Chamber of the Court of appeal has now clarified that the persons having the right to apply for the dissolution of a…

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