Klaus Ilmonen advises on corporate transactions involving public corporations. His practice includes public takeovers, equity capital markets, and corporate governance of publicly traded corporations. He is recognised for his expertise in complex takeover situations and in international capital markets transactions. In public takeovers, Klaus has advised financial sponsors and industrial offerors and the boards and shareholders of acquired corporations. He has participated in drafting Finnish takeover regulation, including the first Helsinki Takeover Code.

Klaus also advises on capital markets transactions, including IPOs, rights offerings, and private offers of securities. He has previously practised U.S. securities law in the London office of the U.S. law firm Cleary, Gottlieb, Steen & Hamilton, where he represented European issuers and underwriters in international securities offerings.

Klaus has been appointed professor of practice at the Hanken School of Economics in Helsinki and teaches corporate and securities law. He has also served on a consultative group for developing EU corporate finance regulation.

Klaus has been deployed with Finnish forces in Afghanistan, Kosovo, and Lebanon, and he serves as the managing director of the Mannerheim-Foundation in Finland.

Rankings

  • Hall of Fame, Capital Markets, Legal 500, 2025
  • Recognised as a Market Leader in Capital Markets, IFLR1000, 2024
  • Hall of Fame, Capital Markets, Legal 500, 2024
  • Ranked in Capital Markets, Chambers Global, 2025
  • Ranked in Capital Markets, Chambers Global, 2024
  • Ranked in Capital Markets, Chambers Europe, 2024
  • Received Defensor Legis’ Authors’ Award for his 2023 article “Yhtiö muutoksessa – yritysohjauksen politiikkaa” addressing the impact of the evolving political landscape and increased awareness of corporate externalities on corporate governance and corporate law.
  • 'Klaus Ilmonen is described as a "very well-respected, skilful and experienced capital markets lawyer."', Capital Markets, Chambers Global 2022
  • "Klaus Ilmonen is the brilliant head of the practice", Capital Markets, Legal 500, 2020
  • Leading individual, Capital Markets, Legal 500, 2020-2022
  • "Clients say he has an 'encyclopedic knowledge of the issues and is very collaborative when working with the other side.'", Chambers Europe 2020
  • "Impeccable legal knowledge and commercial understanding.", IFLR1000, 2020
  • Ranked as a Market leader in Capital Markets in the 2019-2021 editions of IFLR1000
  • "Sources say that Klaus Ilmonen is 'responsive, pragmatic and easy to work with. He is also extremely experienced and knowledgeable so he really ticks all the boxes.' One interviewee enthuses: 'Klaus is a clear professional in all aspects: technical knowledge, commercial awareness, effectiveness and client service.'", Chambers Europe 2018
  • Ranked among the best lawyers in Capital Markets in the 2015-2021 editions of Chambers Europe
  • "Klaus Ilmonen is ‘one of the few experienced lawyers in the Finnish IPO market’ ", Capital Markets, Legal 500, 2015
  • Ranked among the best lawyers in the 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 and 2017 editions (Helsinki: Capital Markets, Mergers and Acquisitions) of Best Lawyers®

Memberships and Positions of Trust

  • Professor of Practice, Hanken School of Economics
  • Managing Director of the Mannerheim Foundation
  • Expert Group on Securities Regulation, The Finnish Bar Association (2008–2020)
  • Consultative Working Group on Corporate Finance, ESMA (2011–2017)

Professional Background

  • Partner, Hannes Snellman, 2007–
  • Cleary, Gottlieb, Steen & Hamilton, London, 1999–2002

Education

  • Doctor of Laws, University of Helsinki, 2016
  • Harvard Law School, Visiting Researcher, 2011–2012
  • LL.M. (Stone Scholar), Columbia University, 1999

Publications

  • “The Securitisation of the Economy and Geoeconomic Risks – New Frameworks for Business”, DL 4,5 (2023)
  • “The Evolving Corporation – The Politics of Corporate Governance”, DL 3 (2023), Defensor Legis Article Award 2023
  • “Corporate Governance and Accountability in an Evolving Political Environment”, European Business Law Review (2021)