Skip to content

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.



Corporate and M&A



Allen & Overy LLP
One Bishops Square
E1 6AD

View office →



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

News & insights

Science lab setting with plant, computer, flask and microscope

Blog Post: 20 JULY 2021

The UK Competition and Markets Authority imposes record fines for excessive pricing and anti-competitive “pay-for-delay” agreements for hydrocortisone tablets

The UK Competition and Markets Authority (CMA) has imposed over GBP260 million in fines on several drug makers for two breaches of competition law: (i) charging excessive and unfair prices, in breach…

Read more
Digital device

News: 26 MAY 2021

A&O is advising Liberty Global on its Edge data centre joint venture with Digital Colony Partners

LONDON – Allen & Overy is advising Liberty Global on its proposed joint venture with Digital Colony Partners, the digital infrastructure arm of Colony Capital, to create AtlasEdge Data Centres, a…

Read more
Microscope with lights on

Blog Post: 25 MAY 2021

Multilateral task force seeks public input on approach to pharma mergers

Overview FTC-led Multilateral Pharmaceutical Merger Task Force seeks public input on approach to analysing mergers.  Comes at a time when Democratic FTC Commissioner Rohit Chopra has…

Read more
Multiple test tubes and dropper

Blog Post: 23 MARCH 2021

FTC launches multilateral working group with EU, UK and Canadian antitrust authorities to take tougher stance on pharmaceutical mergers

Key points Working group’s goal is “concrete and actionable” updates to pharmaceutical merger analysis. Focus will include new theories of harm beyond the traditional approach of assessing…

Read more