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Thomas Masterman



Masterman Thomas
Thomas Masterman



Tom is counsel in our global antitrust group, based in London. His practice covers all aspects of UK and EU competition law, with particular expertise in the life sciences, financial services and TMT sectors.

Tom regularly handles complex antitrust investigations before the EU Commission and national competition authorities and has acted on a number of the largest global cartel cases over the past decade, as well as representing clients in cartel-related litigation and advising on defences to follow-on damages actions before the courts. He also has an established track record of securing approval for clients on multi-jurisdictional mergers and joint venture arrangements (including Phase II and remedies cases), and has advised on some of the highest-profile M&A transactions in the market in recent years.

Tom’s recent merger control experience includes advising 21st Century Fox on the EUMR merger and UK regulatory aspects of its GBP27.7 billion takeover bid for Sky, the subsequent GBP11.6 billion sale of its 39% stake in Sky to Comcast, and its USD71 billion acquisition by The Walt Disney Company; Endemol Shine Group on the worldwide merger control aspects of its sale to Banijay; and Tullett Prebon on the CMA clearance (with remedies) of its GBP1.6 billion acquisition of rival ICAP. Tom is currently advising Liberty Global plc on its GBP31 billion deal with Telefónica SA to merge Virgin Media (the UK subsidiary of Liberty Global) and O2. On the behavioural side, Tom has advised on a number of major global cartels including the FX spot trading, auto-parts, credit default swaps, gas insulated switchgear, and heat stabilisers investigations.

Tom is listed in the 2020 Legal 500 directory as a “rising star” and a “superb competition lawyer” and client’s note that “Technically, he is very strong, but more importantly for us, he also has the ability to apply his knowledge to the specific commercial context and discern what the real risk is… adding real value to our decision-making.” He is recognised by Chambers and Partners as demonstrating “high levels of technical expertise, coupled with a commercially minded and pragmatic approach” and Who’s Who Legal notes that he “combines deep industry knowledge with top-drawer intellect to solve client problems.” 

Other noteworthy experience includes advising:

  • Grünenthal on its acquisitions from Astra Zeneca of Nexium, Vimovo and Zomig®.
  • Endemol Shine Group on the worldwide merger control aspects of its sale to Banijay.
  • Hitachi on its acquisition of JR Automation Technologies and Hitachi Automotives Systems, Ltd on its proposed acquisition of Chassis Brakes International and on the auto-parts JV with Honda.
  • Tullett Prebon on the CMA clearance (with remedies) of its GBP1.6bn acquisition of rival ICAP.
  • Maersk as compliance counsel for all competition related aspects of the 2M vessel sharing arrangement.
  • Fox Networks Group on the investigation by the European Commission into alleged anti-competitive behaviour in the sports rights business.
  • HSBC in relation to the European Commission’s high profile credit default swap investigation.
  • Chemtura as immunity recipient on the EC heat stabilisers cartel investigation.
  • Macquarie Energy Leasing on its smart meter financing arrangements with British Gas and other energy suppliers.
  • News UK on the competition and regulatory matters relating to its GBP220.3m acquisition of the Wireless Group.



Allen & Overy LLP
One Bishops Square
E1 6AD

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Admitted as solicitor, England and Wales, 2006

Admitted as solicitor, Ireland, 2016


BA, European Legal Studies, Durham University

Erasmus Programme, Katholieke Universiteit Leuven

Experience highlights



Top 3, Global Elite firms

Global Competition Review 2020

TMT Firm of the Year

Legal 500 UK Awards 2019

Competition Team of the Year

British Legal Awards 2018

Published work

  • Philip Mansfield, Thomas Masterman, Jack Ashfield, (2020) “Global cartel enforcement report”, Allen & Overy LLP
  • Philip Mansfield, Thomas Masterman, Laura Harvey, (2019) “Global cartel enforcement report”, Allen & Overy LLP