Department profile
Advokatfirmaet Thommessen AS

Competition/Antitrust

Europe Guide 2026 : Norway


Advokatfirmaet Thommessen AS

Rankings

About

Provided by Advokatfirmaet Thommessen AS

Thommessen is a leading firm within the field of EU/EEA and competition law in Norway. We assist Norwegian and foreign companies with merger control processes, investigations, appeals and litigation proceedings and provide ongoing advice related to competition law, state aid law and other EEA law.

Since the EEA Agreement was signed in 1992, our lawyers have played an active role in the development of both EU/EEA law and Norwegian competition law. We were involved in drafting the legislation and have assisted Norwegian and foreign clients in an impressive of major and landmark cases – including as counsel before Norwegian courts, the Competition Appeals Board, the EFTA Court and the European Court of Justice.

We have been involved in most major cases within this area of law in Norway – from complex merger cases to possible violations of competition rules. Several of the cases have left significant footprints in judicial development and have been of great financial and commercial significance for our clients.

With this as a basis, we assist in transactions, contract negotiations and other commercial project work, in dispute resolution and in major investigations within a wide range of industries. We strive at being a constructive, solution-oriented and accessible partner.

Thommessen is generally recognised as having one of the country's top teams of specialists, and we have for many years been ranked in the top tier of independent surveys. 

Industries (27)

  • Aerospace & Defence
  • Automobiles & Parts
  • Banks
  • Chemicals
  • Commercial & Professional Services
  • Construction & Materials
  • Consumer Product Manufacturing
  • Energy
  • Financial Services
  • Food & Drink Producers
  • Forestry & Paper
  • Government
  • Health Care
  • Industrial Engineering
  • Insurance
  • Media
  • Mining & Metals
  • Pharmaceuticals & Life Sciences
  • Real Estate
  • Retail
  • Software & Computer Services
  • Sports
  • Technology, Hardware & Electronics
  • Telecommunications
  • Transportation
  • Travel & Leisure
  • Utilities

Chambers Review

Provided by Chambers

Competition/Antitrust - Norway

Band 1

Band 1


What the Team is Known For

Advokatfirmaet Thommessen remains one of the leading competition law firms on the Norwegian market thanks to its ability to handle high-profile follow-on damages actions and complex phase II merger control filings. The team also offers experience in behavioural investigations, challenges to authority decisions and competition law compliance mandates. It is a popular choice with clients from the grocery, energy and financial services industries. Team members have experience in both contentious and non-contentious public procurement mandates, often in the healthcare and transportation sectors.

Work Highlights

Provided by Chambers

  • Thommessen represented NorgesGruppen in an appeal against fines imposed for an alleged cartel in the grocery sector.

Strengths

Provided by Chambers

  • Thommessen’s competition team combines exceptional legal expertise with deep market understanding and strategic insight.

    Competition/Antitrust respondentEurope
  • Thommessen has demonstrated strong capabilities in efficient project management. The lawyers provide practical, relevant, and well-targeted advice that is carefully tailored to the needs of our organisation.

    Competition/Antitrust respondentEurope
  • The firm has a strong group of professionals with expertise across various aspects of public procurement and competition law.

    Competition/Antitrust respondentEurope
  • The team is consistently available, replies promptly to inquiries, and provides clear and actionable advice. Its ability to follow up and adapt to our timelines has been excellent.

    Competition/Antitrust respondentEurope

Notable Practitioners

Provided by Chambers

  • Band 1Siri Teigum
    Band 1Siri Teigum

    Siri Teigum

    Siri Teigum stands out for her handling of contentious competition law matters, including representing clients in high-profile behavioural investigations and significant damages actions. She additionally assists clients with merger control filings, including those requiring phase II investigations.

    • Siri Teigum is very knowledgeable and experienced.

      Competition/Antitrust respondentEurope
    • Siri Teigum is a fantastic competition lawyer.

      Competition/Antitrust respondentEurope
    • Siri Teigum is the best hall of famer.

      Competition/Antitrust respondentEurope
    • Siri Teigum is especially skilled at explaining complicated matters in a way that business people understand.

      Competition/Antitrust respondentEurope
  • Band 2Eivind Vesterkjær
    Band 2Eivind Vesterkjær

    Eivind Vesterkjær

    Eivind Vesterkjær has a broad competition law practice. He advises clients on FDI filings and merger control investigations. He has further experience representing clients in investigations into alleged illegal information exchanges and assists with competition law compliance mandates.

    • He is an experienced and solution-oriented lawyer who delivers good commercial advice.

      Competition/Antitrust respondentEurope
    • Eivind Vesterkjær has a friendly and humble approach. He gives first-rate and extremely thorough advice in complex matters, with a strong understanding of commercial consequences across industries.

      Competition/Antitrust respondentEurope
    • Eivind Vesterkjær is a very reliable lawyer who delivers top-notch products. He is a trusted adviser and a skilful competition lawyer.

      Competition/Antitrust respondentEurope
  • Band 3Svein Terje Tveit
    Band 3Svein Terje Tveit

    Svein Terje Tveit

    Svein Terje Tveit acts for clients on behavioural investigations and market inquiries. He has further experience in the overlap between sustainability and competition law. He also handles state aid issues. He joined Advokatfirmaet Thommessen in December 2025.

    • Svein Terje Tveit is a solution-oriented expert who makes complex material easy to understand. He is an excellent devil's advocate who brings out the best in us.

      Competition/Antitrust respondentEurope
    • Svein Terje Tveit is a dedicated and highly skilled lawyer in both public procurement law and competition law. He is very pleasant to work with.

      Competition/Antitrust respondentEurope
    • He combines deep legal expertise with sharp strategic thinking. He has an exceptional ability to communicate complex legal matters in a clear manner.

      Competition/Antitrust respondentEurope
    • Svein Terje Tveit balances the legal side against business considerations and left a positive impression with the clients. He is always timely, always providing high quality, understanding and empathic.

      Competition/Antitrust respondentEurope
    • Svein Terje Tveit is efficient, skilled in his field and highly capable in the art of translating complex legal terminology into language that is understandable.

      Competition/Antitrust respondentEurope
  • Band 3Wenche Sædal
    Band 3Wenche Sædal

    Wenche Sædal

    Wenche Sædal has a strong focus on assisting clients from the transport sector with contentious public procurement mandates, including representing them in interim injunctions.

    • Wenche Sædal was competent, efficient and nice.

      Competition/Antitrust respondentEurope
    • She provides great quality and fast response times.

      Competition/Antitrust respondentEurope

Ranked Individuals at Advokatfirmaet Thommessen AS (5)

Norway

Members

Provided by Advokatfirmaet Thommessen AS

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