"He's extremely flexible, pragmatic and quickly provides excellent advice." (clients)
Chambers Global 2016


Klaus Riehmer is a senior counsel in the Frankfurt office of Mayer Brown's Corporate practice and a member of Mayer Brown’s global M&A leadership group. He advises on national and cross-border M&A transactions, including public takeovers, as well as private M&A and corporate projects. He also advises on corporate law and corporate restructurings. During his practice of so far more than 20 years, Klaus has been involved in numerous significant M&A projects in a variety of industries and sectors, especially in the areas of financial services, automotive, chemical, pharmaceuticals, telecommunications and IT.

Klaus has been recognized as a leading German corporate and M&A lawyer by various independent directories, including JUVE, Chambers Global, Chambers Europe, IFLR 1000 and Best Lawyers.

Klaus is a member of the faculty and speaker at the postgraduate program Executive Master of European and International Business Law (E.M.B.L.-HSG) of the University of St. Gallen. He is widely published especially on German takeover law and corporate law. Klaus is co-editor and co-author of Being a Board Member in Germany, an English-language guide for board members of German companies.

Before joining Mayer Brown in 2015, Klaus was a partner at another premier international law firm in Frankfurt.

Spoken Languages

  • German
  • English
  • Spanish


  • Advised Beijing Enterprises Holdings Limited on the acquisition of EEW Energy from Waste GmbH from Swedish investor EQT for a purchase price of approximately EUR 1.4 billion. This acquisition was until then the largest M&A transaction of a Chinese company in Germany. 
  • Advised Publicis Groupe on the squeeze-out of minority shareholders of Pixelpark AG.
  • Advised on privatization of Deutsche Pfandbriefbank AG.
  • Advised on merger of one of the largest European companies in the construction material sector and on the sale of business units.
  • Advised a global US company in connection with various transactions in Germany and Central Europe.
  • Advised a German chemical company on the acquisition of a major business unit.
  • Advised investors regarding the controversial reorganization of the boards of a listed German company in the plastics industry.
  • Advised a German state bank on the acquisition of a significant business unit of former WestLB.
  • Advised a large French company on the acquisition of a German group for communications and e-business solutions.
  • Advised a large German transport company on the acquisition of the largest private railway company in Poland.
  • Advised on the merger between HypoVerereinsbank and Unicredit, one of the largest cross-border bank mergers in Europe.
  • Advised on the takeover of Mannesmann by Vodafone, to date the worldwide largest M&A transaction.


LLM, University of Texas, 1994

Second State Law Examination (bar exam), Hamburg, 1993

Research fellow and assistant, Max-Planck-Institute for Comparative and International Private Law, Hamburg, 1989-1993

Doctor’s degree (PhD in law, corporate law), University of Kiel, 1992

Legal Clerkship (Referendariat), Hamburg, 1989-1993

First State Law Examination, Munich, 1989

Law studies at the universities of Freiburg and Munich


  • Frankfurt am Main, Germany


  • International Bar Association
  • German-Spanish Lawyers Association
  • "Highly regarded" for M&A and for Restructuring and insolvency - IFLR 1000 2022
  • "Highly regarded" for M&A and for Restructuring and insolvency - IFLR 1000 2021
  • Recognized by The Best LawyersTM in Germany  2018, 2019, 2020, 2021 and 2022 for Corporate and Mergers and Acquisitions Law
  • "Notable practitioner" for Corporate/M&A – Chambers Global and Chambers Europe 2020
  • Ranked in Band 1 for Corporate/M&A: Mid-Market in Germany – Chambers Global and Chambers Europe 2020
  • "Klaus Riehmer benefits from impressive experience in international M&A deals, including joint ventures. He handles both public and private M&A." – Chambers Global and Chambers Europe 2020
  • "Highly regarded" in the area of M&A as well as Restructuring – IFLR 1000 2020
  • "Frequently recommended lawyer" in the areas of Corporate Law and M&A – JUVE Handbook 2019/2020
  • Recommended for Corporate Law and M&A - medium-sized deal – Legal 500 Germany 2019
  • Named as one of the "leading names" in Corporate Law and M&A – medium-sized deals – Legal 500 Germany 2019
  • Clients enthuse that department head Klaus Riehmer is "tough, knowledgeable and commands a strong amount of authority in negotiations based on his large scope of experience." – Chambers Europe 2019
  • Highly regarded for M&A and Restructuring & insolvency – IFLR 1000 2019
  • "often recommended lawyer" in the area of corporate and M&A – JUVE Handbook 2018/2019
  • Klaus Riehmer is acclaimed as a leading mid-market M&A lawyer who is also known for his strength in corporate restructuring and corporate advisory work. – Chambers Global 2018 and Chambers Europe 2018
  • "Recommended lawyer" in the areas of Corporate and M&A – Legal 500 Germany 2018
  • "Frequently recommended lawyer" in the areas of Corporate and M&A – JUVE Handbook 2017/2018
  • "extremely fast response times" (client) – JUVE Handbook 2017/2018
  •  Klaus Riehmer stands out as one of the most active lawyers in mid-market M&A. – Chambers Global 2017 and Chambers Europe 2017
  • "He is very knowledgeable, user-friendly and experienced. He is good at advising clients on cross-border situations." (client) – Chambers Global 2017 and Chambers Europe 2017
  • "one of the best Public M&A lawyers in the market" (competitor) – JUVE Handbook 2016/2017
  • "He's extremely flexible, pragmatic and quickly provides excellent advice." (clients) – Chambers Global 2016 and Chambers Europe 2016
  • "tremendous expertise on public takeovers" – JUVE Handbook 2015/2016
  • "extremely renowned M&A lawyer" – JUVE Handbook 2015/2016
  • "Exceptional transaction lawyer, also knows the specifics of the finance industry." (client) – JUVE Handbook 2014/2015
  • "He is very familiar with M&A transactional work and manages projects well." – Chambers Global 2015 and Chambers Europe 2015
  • "He has a strong understanding of complex structures." – Chambers Global 2014 and Chambers Europe 2014
  • "First choice for large deals." (client) – JUVE Handbook 2012/2013
  • "Constant, reliable best quality." (client) – JUVE Handbook 2012/2013
  • "He knows the banks very well and provides more than just legal advice – he gives full market intelligence." (client) – Chambers Global 2013 and Chambers Europe 2013
  • "He´s excellent at negotiating with the sellers, and knows these transactions and how they work inside out." (client) – Chambers Global 2013 and Chambers Europe 2013
  • "He is not only one of the best lawyers in Germany, he´s one of the best lawyers in Europe!" (client) – Chambers Global 2012 und Chambers Europe 2012
  • "He is valued in all our departments." (client) – JUVE Handbook 2010/2011
  • "Sources characterize Klaus Riehmer as a pragmatic and well-mannered lawyer." – Chambers Global 2011 and Chambers Europe 2011
  • "Energetic, forceful, and endlessly experienced, Klaus Riehmer focuses his practice on private and public M&A transactions." – Chambers Global 2009 and Chambers Europe 2009