Henry Mostyn’s practice focuses on EU and UK competition law, including merger control, anticompetitive agreements, and abuse of dominance rules.

Henry has represented clients before the European Commission and the UK Competition and Markets Authority, as well as litigation before the European Courts in Luxembourg and the UK High Court. His particular focus is on the application of the abuse of dominance rules to the technology sector.

Henry joined the firm in 2012 and became a partner in 2022. He was resident in the firm’s Brussels office from 2012 and moved to the London office in 2014. Previously, he completed pupillage at 4 New Square Chambers, Lincoln’s Inn. He has a background in mathematics.

During 2017, Henry worked at the UK Competition and Markets Authority in the mergers team.

Notable Experiences

  • DuPont in connection with a European Commission investigation into a collaborative arrangement between DuPont and Honeywell to develop a new automotive refrigerant

  • Google in the EU Commission’s landmark Shopping decision and subsequent appeal to the European General Court in Luxembourg 

  • Google in the EU Commission’s investigation regarding the Android mobile operating system

  • Google in the UK online map provider Streetmap’s litigation

  • Google in various global matters, including the closed investigation by the Taiwan Fair Trade Commission into maps, and the investigation by the Competition Commission of India

  • Lafarge in its $50 billion merger of equals with Holcim

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Publications

Competition Appeal Tribunal Sets Aside CMA’s First Antitrust Fine for Most Favoured Nation Clauses in its Compare the Market Decision,” by Henry Mostyn and Jonas Zenger, Cleary Antitrust Watch blog, August 12, 2022

New UK Framework for Vertical Agreements Finalised,” by Henry Mostyn and Gee Kim, Cleary Antitrust Watch blog, August 3, 2022

Thank You for the Music – CMA Publishes Update in Music and Streaming Study,” by Henry Mostyn and Anders Jay, Cleary Antitrust Watch blog, August 2, 2022

Unfair Play: UK CMA Fines Pharmaceutical Companies for Excessive Prices,” by Henry Mostyn and Jonas Zenger, Cleary Antitrust Watch blog, August 1, 2022

The Dominance and Monopolies Review – 10th Edition

UK Government Confirms Plans for Digital Markets Regulatory Regime,” by Jackie Holland, Vanessa Marton, Patrick Todd, Anders Jay and Gee Kim, Cleary Antitrust Watch blog, May 6, 2022 

“European Union” and “Global Overview,” Dominance, Getting the Deal Through, April 2022

Final Agreement Reached on Digital Markets Act: A Paradigm Shift In Digital Regulation,” by Henry Mostyn and Nuna Van Belle, Cleary Antitrust Watch blog, March 29, 2022

Wide-Ranging New UK National Security Regime Comes Into Force,” by Nicholas Levy, Maurits Dolmans, Jackie Holland, Tihir Sarkar, Michael J. Preston, Sam Bagot, Gabriele Antonazzo, Nallini Puri, Michael James, Paul Gilbert, Henry Mostyn, and John Messent, Cleary Gottlieb Alert Memorandum, January 2022

Co-editor and Preface co-author, with Maurits Dolmans, The Dominance and Monopolies Review, 2016, 2017, 2018, 2019, 2020, and 2021; and co-author, “European Union” chapter, 2020 and 2021

“European Union” and “Global Overview,” Dominance, Getting the Deal Through, April 2021 

“European Union - Access to Online Platforms and Competition Law,” Global Competition Review, October 12, 2020

“European Union” by Patrick Bock and Henry Mostyn, Dominance, Getting the Deal Through, August 2020

Reforming EU Merger Control to Capture ‘Killer Acquisitions’ – The Case for Caution,” by Nicholas Levy and Henry Mostyn, Competition Law Journal, July 2020

‘Exploitative’ Abuse of Dominance and ‘Price Gouging’ in Times of Crisis,” co-author with George S. Cary, Maurits Dolmans,  Bruce Hoffman, Thomas Graf, Leah Brannon, Richard Pepper, Alexis R. B. Lazda, Savannah Haynes, Kristi Georgieva, and Jan Przerwa, Cleary Gottlieb Alert Memorandum, March 2020; republished by Concurrences, April 30, 2020

Co-editor and Preface co-author, with Maurits Dolmans, of The Dominance and Monopolies Review, 2016, 2017, 2018, and 2019; and author, “European Union,” The Dominance and Monopolies Review, 7th edition, 2019

“European Union” by Patrick Bock, David Little, and Henry Mostyn, Dominance, Getting the Deal Through, 2019, p. 76-84

Competition in Display Ad Technology: A Retrospective Look at Google/Doubleclick and Google/Admob,” by Maurits Dolmans, Henry Mostyn, Daniel Bitton, and David Pearl, CPI Antitrust Chronicle, April 2019

European Champions – Why Politics Should Stay Out of EU Merger Control,” by Nicholas Levy, David Little, and Henry Mostyn, Concurrences – Revue Des Droits de la Concurrence, April 2019

Access to Online Platforms and Competition Law,” E-Commerce Competition Enforcement Guide, December 2018

Co-editor and Preface co-author, with Maurits Dolmans, of The Dominance and Monopolies Review, 2016, 2017, and 2018; and author, “European Union,” The Dominance and Monopolies Review, 6th edition, 2018

“European Union” by Patrick Bock, David Little, and Henry Mostyn, Dominance, Getting the Deal Through, 2018, p. 217-223 (Chapter 13)

“The European Union” by Thomas Graf and Henry Mostyn, The Dominance and Monopolies Review, Law Business Research, August 2017, p. 108-126 (Chapter 8)

“European Union” by Patrick Bock, David Little and Henry Mostyn, Dominance, Getting the Deal Through, 2017, p. 66-72 (Chapter 13)

“The European Union” by Thomas Graf and Henry Mostyn, The Dominance and Monopolies Review, Law Business Research, June 2016, p. 108-128 (Chapter 8)

“The European Union” by Thomas Graf and Henry Mostyn, The Dominance and Monopolies Review, Law Business Research, June 2015

“The European Union” by Thomas Graf and Henry Mostyn, The Dominance and Monopolies Review, Law Business Research, June 2014, p. 97-116 (Chapter 7)

“Internet & Antitrust: An Overview of EU and national case law”, M. Dolmans and H. Mostyn, e-Competitions Special Issue

Events

Cleary Gottlieb Webinar, “Implications of the Intel Judgment for Article 102 Enforcement,” March 24, 2022

Cleary Gottlieb Webinar, “UK Antitrust Enforcement: One Year After Brexit,” March 9, 2022


Cleary Gottlieb webinar, “UK Antitrust Enforcement Post-Brexit: What to Expect and How to Prepare,” October 22, 2020

Milan Digital Competition Conference, “Platforms and Regulation,” January 31, 2020

Law Knect Conference, “Platform Competition,” March 22, 2018

ERA Conference 2017, “Anticompetitive Practices in the Online World,” November 2017

ERA Conference 2017, “Dominance and Abuse, Google & Amazon,” October 2017