Weijer VerLoren van Themaat

Advocaat | Partner


+31 20 605 61 83
+31 6 5365 5833



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Weijer specialises in competition law and leads Houthoff’s Competition practice group. He is also head of Houthoff’s Healthcare sector group. Weijer focuses in particular on merger notifications and cartel defence litigation. His work involves issues relating to regulation and competition in healthcare, and advising and assisting healthcare institutions in the context of partnerships.

Weijer represented T-Mobile Nederland in the ‘mobile operators case’ brought by the Netherlands Competition Authority, which eventually resulted in the seminal ‘T-Mobile case’ at the European Court of Justice on the definitions of object and effect in the context of internal market restriction. He also represented Accell Groep, the second largest bicycle manufacturer in Europe, in an appeal against a decision of the Netherlands Competition Authority regarding alleged mutually agreed concerted practices in the form of information exchange. In relation to merger control, he was involved in the EU notification of TomTom’s takeover of TeleAtlas. In relation to healthcare, he assisted the mergers of the ErasmusMC and Havenziekenhuis, the St. Elisabeth Hospital and TweeSteden Hospital, the Kennemer Gasthuis and Spaarne Hospital, and the AMC and VUmc.

  • Leading Individual
    Legal 500, EU and Competition (2023 Edition)
  • "A client stated that 'Weijer is a very senior lawyer who knows everything about competition law'."
    Chambers Global & Europe, EU and Competition (2023 Edition)
  • "A client says: 'he is really intellectual and very knowledgeable'."
    Chambers Global & Europe, EU and Competition (2023 Edition)
  • "A client says: 'Weijer has enormous experience and exceptional insights into healthcare and other markets'."
    Chambers Europe, Healthcare (2023 Edition)
  • "A client mentioned that ‘Gerrit Oosterhuis and Weyer Verloren Van Themaat are experienced and outstanding antitrust lawers, highly specialised, quick thinking and pragmatic'."
    Legal 500, EU and Competition (2023 Edition)
  • Leading Individual
    Legal 500, EU and Competition (2022 Edition)
  • “A client reports that he ‘understands this material very well and has been very responsive and insightful throughout the process’.”
    Chambers Europe, Competition / European Law (2022 Edition)
  • “Clients value his approach, deeming him ‘strong in strategic advice, with an ability to think along and add value to the discussion’.”
    Chambers Europe, Healthcare (2022 Edition)
  • Recommended
    Chambers Europe, Competition / European Law (2021 Edition)
  • “Clients declare him ‘an expert in healthcare transactions.’”
    Chambers Europe, Healthcare (2021 Edition)
  • “Weyer VerLoren van Themaat is a market leader in Holland with deep academic and practical knowledge. He is also a pleasure to work with.”
    Legal 500, EU and Competition (2021 Edition)
  • “Weijer Verloren van Themaat is focused on creating real value in healthcare, knows when to give advice and when not to, and he is a real pleasure to work with.”
    Legal 500, Healthcare and Life Sciences (2021 Edition)
  • “Weijer Verloren van Themaat is a trusted partner for many leaders in the healthcare community.”
    Legal 500, Healthcare and Life Sciences (2021 Edition)
  • “Sources highlight that he ‘has a firm footing in healthcare with a focus on competition law.’”
    Chambers Europe, Healthcare (2020 Edition)
  • “He is well regarded by commentators who describe him as a ‘top competition lawyer in the Netherlands.’”
    Chambers Europe, Competition / European Law (2020 Edition)
  • Recommended
    Legal 500, EU and Competition (2020 Edition)
  • “Weyer VerLoren van Themaat: sound industry knowledge and professionalism and easy to work with and has a practical approach.”
    Legal 500, EU and Competition (2020 Edition)
  • Recommended
    Legal 500, Healthcare and Life Sciences (2020 Edition)
Weijer was a resident partner of the Brussels office from 1997 to 2005. He is a member of the International Bar Association, the ABA, the Dutch Competition Law Association and the Dutch Association for European Law. He is also Chair-Emeritus of Lex Mundi's Antitrust, Competition and Trade group; non-governmental advisor of the Dutch Authority for Consumers and Markets; and chair of the advisory committee of the Netherlands Bar Association. Weijer is the founder and a board member of the competition law foundation Stichting Ontwikkelingen Mededingingsrecht, and has authored and co-authored various books on competition law, including European Competition Law (Edward Elgar) and Nederlands Mededingingsrecht (Kluwer). 

Qualifications & Experience

  • Law (Universiteit van Amsterdam)
  • Advised European private equity firm CastikCapital on the acquisition of TBAuctions, a leading European online auction platform.
  • Advised Yarden, one of the largest funeral service providers in the Netherlands, and its two shareholders (the Vereniging Yarden and the Stichting Yarden) in the sale of Yarden to DELA.
  • Advising on the governance of Martini Ziekenhuis and its Medical Specialists, including advice on the legal structure and setting up cooperation agreements between the Medical Specialists and the Board of the Hospital.
  • Assisted the AMC and VUmc hospitals in obtaining the required approval from the Netherlands Authority for Consumers & Markets (ACM) for an administrative merger. The approval enables the two Amsterdam-based university medical centres to cooperate on patient care, research, education and training without limitation. This will create the biggest university medical centre in the Netherlands.
  • Representing Total in a follow-on damage claim.
  • Houthoff is representing Singapore Airlines Singapore Cargo in various Dutch private enforcement proceedings before the Amsterdam courts. These proceedings were initiated by claim vehicles Equilib, EWD and Stichting Cartel Compensation (SCC) following the EC's decisions in the air cargo case. The first action was initiated in 2010 and all the cases are ongoing.