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Philip Mansfield

Partner Co-Head Antitrust


Mansfield Philip
Philip Mansfield

Partner Co-Head Antitrust


Philip Mansfield is a senior partner in our London antitrust group, who splits his time between the London and Brussels offices. He has led meetings with agencies around the world on merger, cartel and behavioural matters for various clients, including with the European Commission, UK agencies, U.S. Department of Justice, U.S. Federal Trade Commission, U.S. Court of North California, South Korea's Fair Trade Commission, the Japan Fair Trade Commission and China's Ministry of Commerce.

Philip regularly obtains approval for complex mergers and joint venture arrangements, particularly in the high-tech sector and was a winner of the Global Competition Review Matter of the Year in both 2011 and 2012 for merger-related cases. His experience includes advising: HP on its acquisition of Apogee; Cisco on the sale of its NDS business; Hitachi on a number of large M&A transactions including the acquisition of JR Automation and Chassis Brakes International; Sun Microsystems on its acquisition by Oracle; Seagate on its acquisition of Samsung HDD and Xyratex; and Github on its sale to Microsoft.

Philip has extensive cartel experience and is a regular speaker at the signature IBA/ABA cartel conference. In 2016 Philip won Global Competition Review Behavioural Matter of the Year for the firm’s role on the European Commission’s credit defaults swap investigation. Matters include advising a party in the first EU settlement case (DRAM); as well as advising parties in each of the FX, Rubber Chemicals, EPDM, Heat Stabilisers, GIS, Power Transformer, LCD, CRT and Auto Parts investigations. More recently Philip has developed extensive experience in advising financial institutions on a number of cartel investigations and Financial Conduct Authority market studies, including strategies surrounding the merits of making immunity/leniency applications to the UK Competition and Markets Authority and the EC and engaging in settlement discussions with the EC. Philip recently successfully guided Newton Investment Management Limited (part of BNYM) through the Financial Conduct Authority’s first ever investigation brought using its competition enforcement powers. He is currently advising clients on their defences to several separate follow-on damages actions before the English and German courts and has represented claimants in the English courts.

Philip has an established track record of representing companies in successfully raising and defending behavioural complaints before the EC and the English courts relating to interoperability (Sun Microsystems/Microsoft, PSI/IBM), bundling (Microsoft/Opera, Microsoft/Vista), patent pools (Premaitha, DVD6C/iODRA) and patent ambush (Micron/Rambus). 

“Philip Mansfield is a seasoned expert in competition law who is highly respected for this profound ability in merger and behavioural issues” - Who’s Who Legal 2019

Philip is described as a “sharp lawyer who is very business-orientated and knows what we need to do to achieve our goals” - Chambers UK 2019 (Competition)

Clients report that Philip Mansfield “has a wonderful ability to synthesise competing considerations into clear, practical advice in high-pressure situations” - Chambers UK 2018 (Competition) 

Experience highlights

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Admitted as solicitor (England and Wales), 1995

Admitted as solicitor (Ireland), 2018


MA, Downing College, Cambridge University

Other noteworthy experience 


  • Fox Networks Group on the investigation by the European Commission into alleged anticompetitive behaviour surrounding the acquisition of EU sports rights.
  • Hitachi on various global cartel matters, including the LCD, CRT, GIS and Power Transformers investigations, and associated damages claims before the English Courts.
  • Seagate on the EU and worldwide merger control aspects of its USD1.4bn acquisition of the hard disk drive business of Samsung Electronics.
  • Sun Microsystems on the EU merger control aspects of its USD7bn merger with Oracle. This was a high-profile and controversial EU merger investigation which ended in an unconditional clearance decision in the face of significant vocal opposition.
  • Citibank on the multi-jurisdictional investigation by a number of regulators and prosecutors into the manipulation of the foreign exchange (Forex) market, and resulting antitrust damages claims.
  • Micron on the acquisition of a joint controlling interest in Inotera and various other acquisitions.
  • Github on its sale to Microsoft.
  • Cisco on the sale of its NDS business.
  • HP on its GBP380m acquisition of managed print services business Apogee from private equity fund Equistone and management sellers.

Pro bono 

He is a trustee of Allen & Overy’s London Foundation and a Governor of the Raines Foundation School.



Top 3, Global Elite firms

Global Competition Review, 2020

Competition Team of the Year

British Legal Awards, 2018

Competition Team of the Year

Legal Business Awards 2017