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Thomas Masterman



Image of Thomas Masterman
Thomas Masterman



Tom has over 15 years’ experience advising clients on complex international, EU and UK merger clearances, including some of the highest-profile M&A transactions in the market in recent years.

He also has an established track record of advising on cartel and abuse of dominance investigations, national security / foreign direct investment reviews and market investigations. Tom’s practice spans a broad range of sectors, with particular expertise in infrastructure, life sciences and TMT.

Tom is listed in the Legal 500 directory as a “rising star” and a “superb competition lawyer”. He is also ranked as “future leader” by Who’s Who Legal, who note that he “combines deep industry knowledge with top-drawer intellect to solve client problems.”

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Strips of pharmaceutical pills

News: 24 November 2022

A&O advises KKI on joint venture collaboration agreement with Grünenthal for established medicines portfolio

Allen & Overy’s Healthcare Transactions Team has advised Japan-based global specialty pharmaceutical company Kyowa Kirin International (KKI) on its joint venture collaboration with global…

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Publications: 09 November 2022

Advocate General’s Opinion in Commission v CK Telecoms

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Publications: 23 September 2022

The National Security and Investment Act 2021: A Snapshot of experience so far

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Blog Post: 24 August 2022

Pfizer and Flynn Pharma fined GBP70m for excessive and unfair pricing after UK antitrust reassessment

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Experience highlights



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

Other noteworthy experience


  •  Liberty Global on merger control and FDI clearances for the establishment of its pan-European data centre platform (AtlasEdge).
  • Grünenthal on numerous M&A matters, including its acquisition from Astra Zeneca of Nexium, Vimovo and Zomig®.
  • Macquarie Asset Management on antitrust and regulatory aspects of its acquisition of Southern Water.
  • Endemol Shine Group on EU and global merger control clearances of its sale to Banijay.
  • Hitachi Automotive Systems on its acquisitions of JR Automation Technologies and Chassis Brakes International and on its global 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 credit default swap investigation.
  • News UK on various matters, including its GBP220.3m acquisition of the Wireless Group, the CMA’s online advertising market study and its DCMS application to vary The Times Undertakings.

Published work

  • Philip Mansfield, Thomas Masterman, Imogen Carr (2022) “Global antitrust enforcement report”, Allen & Overy LLP
  • Thomas Masterman (2021) “FTC launches multilateral working group with EU, UK and Canadian antitrust authorities to take tougher stance on pharmaceutical mergers”, Allen & Overy LLP
  • Philip Mansfield, Thomas Masterman, Imogen Carr (2021) “Global antitrust enforcement report”, Allen & Overy LLP
  • Thomas Masterman (2020) “European Commission completes current cycle of pay-for-delay probes with fines imposed on Teva and Cephalon”, Allen & Overy LLP



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