Patrick J. Harrison

PATRICK HARRISON has over 20 years’ experience advising on all aspects of EU and UK competition law. He spent four years in Brussels before relocating to Sidley’s office in London in 2007 and is admitted as both a Solicitor in England and Wales and an Advocaat in Belgium. Patrick has significant experience representing clients before the European Commission and the UK’s Competition and Markets Authority (CMA), securing favorable results for clients requiring regulatory approvals or facing regulatory challenges.

Patrick focuses his practice on merger control, cartel and dominance investigations, counseling, and compliance. He has also represented clients in EU and UK judicial review proceedings regarding both competition cases and legislation of broader application. In this context, he has pleaded a number of cases before the EU courts.

Patrick has received acknowledgement from numerous industry- ranking guides, including, most recently:

• Chambers UK, Europe, and Global 2026 – Ranked for Competition Law, with sources commenting “Patrick Harrison is a very commercially-minded regulatory advisor and is extremely creative in his problem solving, for what are fairly complex and novel legal queries,” and “Whenever there is a messy competition matter, he’s the guru we rely on.”
• Legal 500 UK 2026 – Ranked for EU and Competition, with clients saying “Patrick Harrison is fantastic to work with, pragmatic, knowledgeable, and constructive.” He is also recommended for Life Sciences and Healthcare.
• Lexology Index 2026 – Recommended for Competition.

Patrick has published widely on EU and UK competition law issues and has presented at a number of industry events.

In recent years, Patrick has advised:

• Welltower Inc, a leading real estate investment trust, on multiple UK investments, including the CMA’s investigation of Welltower’s 2025 acquisitions of care homes operated by Barchester, Aria, Danforth, and HC-One.
• TowerBrook Capital Partners on multiple deals, including
  • its 2020 sale of metals recycler Metallo to rival Aurubis, a deal that was subject to a Phase II review by the European Commission but cleared unconditionally following arguments made at the Oral Hearing. The deal is one of only a handful of cases in recent years that have been subject to a formal Statement of Objections from the Commission but resulted in an unconditional approval; and 
  • its 2025 sale of French-headquartered railway sleeper (or “tie”) manufacturer Sateba to railway infrastructure group Vossloh, a deal that was cleared subject to behavioral conditions at Phase I in France, and cleared unconditionally at Phase I in eight other European jurisdictions, notwithstanding active opposition from a third- party complainant.
• Leading medical device manufacturer Stryker Corporation on multiple transactions, including: 
  • its US$4.9 billion acquisition of Inari Medical, a medical device manufacturer; and
  • its 2023 US$500 million purchase of Cerus Endovascular, which required antitrust approvals in the U.S., the UK, Germany, and Austria.
• Leading medical imaging and diagnostics player GE Healthcare on:
  • its 2026 US$2.3 billion acquisition of Intelerad, a leading medical imaging software provider, which required antitrust approvals in the U.S., Canada, and Australia; and
  • its 2024 £40.5 million acquisition of Intelligent Ultrasound Limited, a UK-based artificial intelligence company operating in the medical devices sector.
• Hoffman La-Roche on multiple transactions, including:
  • its 2025 US$3.5 billion acquisition of 89bio Inc, a publicly listed clinical-stage biopharmaceutical company;
  • its 2024 US$1.5 billion acquisition of biopharmaceutical company Poseida Therapeutics Inc;
  • its 2024 US$850 million acquisition of breast cancer assets from Regor Therapeutics Inc;
  • its 2024 US$1.2 billion sale of a large-scale biologics manufacturing facility to Lonza Group AG, one of the world’s largest healthcare development and manufacturing organizations. The transaction triggered merger control filings in Japan, Switzerland, and the U.S.
  • its 2024 US$3.1 billion acquisition of Carmot Therapeutics, a biotech focused on GLP1 diabetes and obesity treatments, a deal which entailed processes with the UK’s CMA and the European Commission.
• Leading payment technology player Mastercard:
  • on the first investigation by the UK’s Payment Systems Regulator under the Competition Act 1998; and
  • in relation to UK and EU judicial review proceedings initiated by American Express regarding competition law-derived aspects of the EU’s Interchange Fee Regulation and second Payment Services Directive.
• A financial services provider in relation to the first investigation by the UK’s Financial Conduct Authority under the Competition Act 1998.
• Recall Corporation in its acquisition by rival document management provider Iron Mountain, Inc. for US$2.6 billion. The deal was subject to a detailed Phase II investigation by the CMA, at the expiry of which it was approved subject to divestments which were limited to Northern Scotland.
• eBay, Inc. on its 2019 acquisition from Cox Automotive of Motors.co.uk, a UK-based vehicle advertising rival to eBay’s own eBay Motors and Gumtree Motors offerings. The UK’s CMA cleared the deal unconditionally at Phase I, notwithstanding that the CMA had initially raised concerns and called the parties in for an Issues Meeting.
• Blackbaud, Inc. on the 2017 acquisition of its rival, JustGiving, the UK’s leading online charity donations platform. The CMA cleared the Blackbaud/JustGiving transaction unconditionally at Phase I, notwithstanding that the CMA had found the parties had a combined share of 70–80 percent in the UK online fundraising platforms sector.
• Japanese industrial manufacturer Nidec Corporation on the antitrust aspects of its US$1.1 billion acquisition of Embraco, a Brazil-based compressor manufacturer, a deal that was subject to parallel Phase II investigations in the EU, China, Mexico, Russia, and Ukraine.
• IDEX Corporation on a number of acquisitions, including its US$1 billion acquisition of Mott Corporation.
• Buckthorn Partners on a number of deals, including its US$210 million sale of Coretrax to Expro.
• KKR on multiple deals, including:
  
  • its majority acquisition of Biosynth Carbosynth, a Swiss life sciences reagents and custom synthesis and manufacturing services company;
  • its investment in Nordic Bioscience, a Danish biomarker development company; and
  • its participation in a US$530 million funding round in Wolt, a leading European food delivery business based in Finland.

• Law Society of England and Wales European Group