Firm Profile > Advokatfirmaet Thommessen AS > Oslo, Norway

Advokatfirmaet Thommessen AS
0116 OSLO

Banking and finance (including shipping finance) Tier 1

Ellen Teresa Heyerdahl and Tore Mydske jointly lead Advokatfirmaet Thommessen AS’ banking group, heading up the debt financing and financial regulatory teams, respectively. Other key practitioners include Hans Haugstad, who is a key name for cross-border financings; debt capital markets specialists Einar Grette and Halvor Mansåker, and insolvency and restructuring expert Kristoffer Hegdahl. The practice’s expertise encompasses syndicated corporate financings, acquisition finance work, project finance issues, asset financings and real estate-related matters, alongside substantial knowledge of cross-border work, renewable and infrastructure projects, and debt restructuring issues. Jan J Greve and Bjørn Sande Urtegaard are the key contacts in the Bergen office.

Other key lawyers:

Key clients


Nordea Bank

Danske Bank

Svenska Handelsbanken

Skandinaviska Enskilda Banken

GIEK (Norwegian Export Credit Guarantee Agency)

Pareto Securities

ABG Sundal Collier

Nordic Trustee AS

Nordic Credit Rating AS

Vipps AS

Pareto Alternative Investments AS

Storebrand ASA

Sparebank1 Gruppen AS

Capital markets Tier 1

Fielding a ‘solid and very experienced team’, Advokatfirmaet Thommessen AS’ practice is jointly led by Christian Grüner Sagstad and Solveig Fagerheim Bugge and also fields M&A and ECM specialist Hans Cappelen Arnesen, ‘outstanding transaction lawyerAnders Arnkværn and financing expert Einar Grette. The group is notably strong in the IPO market and handles the full range of ECM, DCM and regulatory work; it recently advised Oslo Bors VPS Holding on its acquisition by Euronext and also assisted Kongsberg Gruppen with its NOK5bn acquisition of Rolls-Royce Commercial Marine. Other clients include Goldman Sachs International, DNB Markets and Arctic Securities.

Other key lawyers:


Solid and very experienced team. Always receive senior attention.’

Considered by us to be the most competent and complete legal advisers in the country. Particularly good in financial services, M&A and securities transactions and on international documentation.

Strong team with leading experience and insight.

Efficient work, smooth case handling. (No detours, no unnecessary extra work).’

First class legal knowledge and experience coupled with solid commercial understanding.

Anders Arnkværn is an outstanding transaction lawyer and one of the foremost in his generation. Hans Cappelen Arnesen is perhaps the most trusted legal strategic adviser that we know.

Key clients

Goldman Sachs International

ABG Sundal Collier

Pareto Securities

DNB Markets


Arctic Securities AS

Skandinaviska Enskilda Banken AB

Morgan Stanley

UBS Investment Bank

Fearnley Securities

Saferoad Holding ASA and its sponsor Nordic Capital

Salmones Camanchaca S.A.


Webstep ASA

Elkem ASA

Odfjell Drilling Ltd.

Sparebanken Hedmark Sparebankstiftelse

B2Holding ASA

Oslo Børs VPS Holding ASA

Kongsberg Gruppen ASA

Shelf Drilling, Ltd.

BW Group Limited

BW Offshore Limited

BW LPG Limited

Hafnia Limited

Nordic Trustee AS


Seadrill Ltd

Commercial, corporate and M&A Tier 1

Leveraging its notable M&A strength, Advokatfirmaet Thommessen AS is singled out for its project management expertise and is regularly instructed on high-profile transactions involving multiple jurisdictions. The practice is also active in the energy, oil and gas, shipping, telecoms, financial services and aquaculture sectors with a client roster including Altor Equity Partners, EQT, Odfjell Drilling, Ineos and HitecVision. Group head Christian Grüner Sagstad is a key contact for private equity work, Anders Arnkværn ‘keeps the main priorities in sight’ and Hans Cappelen Arnesen regularly handles ECM work. Other key practitioners include Baard Bale, Ervin Auren, Solveig Fagerheim Bugge , managing associate Øyvind Mork Karlsen and corporate governance expert Stig Berge. The practice also notably strengthened its oil and gas focus through its new Stavanger team with the recruitment of Thomas Abrahamsen, Audun Stornes and newly promoted partner Jone Stakkestad from Kluge Advokatfirma AS in 2020.

Practice head(s):


Strong and versatile M&A experience across sectors; depth and breadth required to handle complex transactions. A client and target-oriented attitude.

Anders Arnkværn has a toned down approach, keeping in sight the main priorities, an ability to relate smoothly with both client and counter-parties, exceptionally efficient in time and process to reaching the main goal, keeps his calm in difficult situations and conflicts.

Key clients

Altor Equity Partners

Triton Partners



Kongsberg Gruppen



Bain Capital

Goldman Sachs

Det Norske Veritas Holding / DNV GL AS

Nordic Capital

SafeRoad Holding ASA

Odfjell Drilling Ltd.


BW Group

Oslo Børs VPS Holding

Belships ASA


CBRE Caledon


Dispute resolution Tier 1

At Advokatfirmaet Thommessen AS, the litigation practice fields specialists in the IP, M&A, tax, insurance, employment, shipping and energy sectors, who act for a client roster encompassing Telenor, Transocean, DNB and Bane Nor. In the team, Eirik W Raanes focuses on IP, contract, construction and insurance law and Henning Harborg is active in white-collar crime cases. Other key individuals include Bergen-based practitioners Trond Hatland and Svein Aage Valen, IP and technology litigator Camilla Vislie and tax and company law expert Hanne Skaarberg Holen. The team was also bolstered by the recruitment of Kristine Hyldmo Bjørnvik in 2019 from Advokatfirmaet Haavind AS, who also made partner in 2020 and is now head of the practice.

Practice head(s):


Thommessen are very knowledgable and are fair in explaining the risks. They will try to get an amicable solution if this is advantageous for the client. They have a huge amount of experience.

Very in-depth, know all details of the case, all members involved and involves the client in all detailed discussions.

Eirik Raanes, with his experience, makes the process clear and provides you with a feeling of comfort. During the process he shows that he is well informed. However, even in stressful times, he uses humour.

Eirik W Raanes has a strong ability to understand complex cases and follow through in the best interest of the client.

Key clients

Telenor ASA

Gyldendal ASA

El Proffen AS

Norwegian Hull Club

Banco Popular Español S.A./Banco Santander

Gard AS/Assuranceforeningen Gard


Intervet International BV/MSD Animal Health

Zimmer Biomet Norway AS

TIAN Holding AS

TGS Nopec Geophysical Company ASA



Kongsberg Gruppen ASA


Sira-Kvina Kraftselskap


Hafslund ASA

Orkla ASA

KLP Skadeforsikring AS

Deloitte AS

Ernst & Young AS


Orange (France Telecom)

BW LPG Holding Ltd.


Hav Line Gruppen AS

Storebrand ASA (and subsidiaries)

Norxe AS/Norxe America, Inc

Storebrand International Private Equity V Limited (“SIPE”)

Westcon Yards AS

Electricity and renewable energy Tier 1

Advokatfirmaet Thommessen AS is notably active across the renewable space and regularly acts for utility clients in the renewable energy, hydroelectric, wind, heating, waste and bioenergy sectors. The practice also stands out for its regulatory expertise and is active in infrastructure and grid operations work alongside experience in project development work, litigation, licensing issues, environmental law and restructuring matters. Practice head Jens Naas-Bibow regularly handles energy licences and energy sector regulatory work; other key practitioners include power regulation expert Gunnar Martinsen, concession law, corporate and tax specialist Bendik Christoffersen and Jacob F Bull, who advises on energy construction projects. Thomas Borch-Nielsen departed to Advokatfirmaet Grette AS.

Practice head(s):

Key clients

Agder Energi AS with subsidiaries

Akershus Energi AS

Eidsiva Energi AS with subsidiaries

Lyse Energi AS with subsidiaries

Nordkraft AS with subsidiaries

NorthConnect KS

Energi Norge

Haugaland Kraft AS with subsidiaries

Engie International Holdings BV

Zephyr AS

Midtfjellet Vindkraft AS

Agder Energi AS with subsidiaries

Employment Tier 1

The practice at Advokatfirmaet Thommessen AS, which ‘gives quick and clear feedback’, is led by senior management and reputational risk expert Stein Kimsås-Otterbech in Oslo, and shipping and oil and gas focused litigator Trond Hatland in Bergen. The group also recently benefited from the recruitment of the highly regarded Tron Dalheim from Arntzen de Besche; Dalheim focuses on contentious work and is active in the oil, energy and aviation sectors. The group handles a variety of contentious and transactional employment mandates and has notable expertise in international matters; the team recently advised on the transfer of 3500 employees in 34 countries from Rolls-Royce to Kongsberg Gruppen. Other clients include Microsoft Norge, Carnegie and Yara International. Managing associate Ingrid Cathrine Nielsen is also a key name to note.


Our impression of the team is that they are aligned and coordinated. They always give quick and clear feedback on requests, and we experienced that clear guidance was given at all times throughout our project.

We worked closely with both Ingrid Cathrine Nielsen and Stein Kimsås-Otterbech. We especially appreciate the availability and timeliness of their responses.

Key clients

Kongsberg Gruppen ASA

NorgesGruppen ASA

Bama Gruppen AS

Microsoft Norge AS

Yara International ASA

Roche Norge

Arbeiderpartiet (Labour Party)

Carnegie AS


Höegh Autoliners Management AS

CGG Services

CapMan Infra and CBRE Caledon

DOF Subsea

Etac AB/Etac AS

EU and competition Tier 1

With expertise across all elements of competition work, Advokatfirmaet Thommessen AS handles antitrust investigations, mergers and joint ventures, procurement work, competition litigation and state aid mandates. Practice co-head and ‘one of Norway’s best competition lawyersSiri Teigum advises on merger issues and disputes, while fellow co-head Eivind J Vesterkjær focuses on the technology, telecoms, offshore, life sciences and distribution sectors. Managing associate Heidi Jorkjend is also a key contact for antitrust investigations. In a recent highlight, the group represented Telenor in the EFTA Surveillance Authority’s investigation of alleged abuse of dominance in the Norwegian mobile communications market; other clients include DNB, Kongsberg Gruppen and Veidekke.


Excellent lawyers: creative, proactive and client friendly.

Very strong team with deep knowledge and understanding of competition and EU law. For Norway – a large team, with the capacity to handle large and complex cases. Very good industry understanding which is key for providing relevant advice.

Siri Teigum is an excellent practitioner. She is one of the top competition litigators in Norway.

Siri Teigum is one of, if not the best, competition lawyer in Norway.

Siri Teigum has unprecedented knowledge and experience when it comes to advising and handling abuse of dominance cases. She has vast experience in dealing with the Norwegian Competition Authority and does extremely well. I have nothing but praise for her.’

Key clients

Telenor ASA


SpareBank 1

Kongsberg Gruppen

Veidekke ASA


Gyldendal ASA, including its subsidiary Ark AS

Finans Norge


NorgesGruppen ASA

Circle K


El-Proffen AS

Fishing and aquaculture Tier 1

Advokatfirmaet Thommessen AS’ fishery and aquaculture team handles the full spectrum of matters in the sector encompassing patent issues, contractual work, transactional matters and financings with notable expertise in regulatory mandates. The practice’s client base spans producers, transportation companies, banks and financiers; notable examples include Pelagia, Sølvtrans, DNB Bank and Biomar. Mons Alfred Paulsen, who clients praise as ‘an outstanding professional in his field’, leads the Bergen-based department and focuses on M&A, corporate and tax issues; Rune Ulriksen Steinsland handles contract law, and recently promoted senior associate Henrik Lovund has experience in contractual issues, M&A and regulatory work.

Practice head(s):


In-depth knowledge of the business, always on the alert and available, excellent capabilities.

Thommessen and the lawyers that we cooperate with in this firm are very service-minded, always available for discussions on short notice. They also have a great understanding of the industry, the players and the topics that we have needed assistance with.

The team has an overall insight to all aspects of our industry, they have a unique network of relations within the industry keeping them updated on hot and relevant topics. The team also has specialists to support us with top-level skills in all possible assignments.

The partners I have dealt with in aquaculture matters have a very good knowledge of the sector, both in Norway and abroad, e.g. South America. They are dynamic and very proactive, always working out solutions. Most importantly, they cover finance and tax aspects of the transactions, but where most lawyers would stop, they also provide regulatory advice and dominate pure operational aspects of the ships, fish and cages.

I will mention Mons Alfred Paulsen in particular. He is an outstanding professional in his field.

Leader of the team, Mons Alfred Paulsen, has, with his extensive knowledge of our industry and his network, created an efficient and capable team.

Both Bergen partners Rune Ulriksen Steinsland and Bjørn Sande Urtegaard are dynamic and pro-active.

Key clients




MSD Animal Health


NCE Seafood/The Seafood Innovation Cluster

DNB Bank

Nordea Bank

Hav Line Gruppen

Austevoll Seafood/ Br. Birkeland




Firda Seafood Group



Insolvency and corporate recovery Tier 1

Advokatfirmaet Thommessen AS excels at a domestic and international level and handles the full breadth of work including financial restructurings, insolvencies, debt negotiations and foreign procedures including Chapter 11 issues and Scheme of Arrangements. The team is particularly recognised for its sector expertise in the oil and gas, offshore and shipping industries; it has been notably active assisting banks and loan syndicates with multiple restructuring projects in the oil services sector. Kristoffer Hegdahl heads up the practice and specialises in financial restructurings; Einar Grette focuses on the bank and bond markets, Halvor Mansåker handles financial restructurings in the bond market, and Ellen Teresa Heyerdahl is an expert in debt financing work.

Practice head(s):

Key clients

Nordic Trustee (+ bondholders committees)


Nordea Bank

Danske Bank


GIEK (The Norwegian Export Credit Guarantee Agency)


ABN Amro


The Export-Import Bank of China (CEXIM)


Eksportkreditt (Export Credit Norway)

Eksportfinans ASA



Danish Ship Finance

SpareBank 1 SR-Bank

Sparebank 1 Søre Sunnmøre

Sparebanken Møre

Skandinaviska Enskilda Banken (SEB)

Insurance Tier 1

Andreas Meidell leads the department at Advokatfirmaet Thommessen AS, which is a key name for marine insurance work; the group recently represented Norwegian Hull Club in a total loss matter relating to a vessel detention in Nigeria. The practice also advises on non-marine insurance, liability and recovery, and regulatory and corporate insurance work for its insurer client base. Henrik Hagberg is singled out for his oil services and shipping expertise, Tore Mydske acts for financial institutions, Trond Hatland is the key contact in Bergen.

Practice head(s):

Key clients


Den norske Krigsforsikring for Skib

Norwegian Hull Club



UK Club


XL Caitlin





AXA Corporate S.A.



Intellectual property Tier 1

The 'analytical and solution-oriented' practice at Advokatfirmaet Thommessen AS is a go-to name in the market for high-profile and complex IP disputes spanning patent, trade mark, trade secret, copyright and unfair competition claims, regularly acting in the Supreme Court. The group is also highly active in major IP transactions and stock exchange listings; the team recently advised Kongsberg Gruppen on the IP aspects of its acquisition of Rolls Royce's commercial marine business. Camilla Vislie heads up the practice, which also fields the highly regarded Eirik W Raanes and managing associate Magnus Hauge Greaker, who focuses on industrial patent law.

Practice head(s):


Thommessen has a good IP team with Eirik Raanes and Magnus Greaker. They work well together and have a good knowledge of IP issues. In addition, they have a good understanding of the industry and know what it is about. That means that they can give good advice.

Dedication is top notch, flexibility in terms of finding ways forward under difficult circumstances is very good, and competence in relevant fields of expertise is superb.

I have mainly worked with Camilla Vislie. She is highly skilled, provides reliable advice on the basis of thorough assessments of the relevant matter.

High theoretical skills and legal knowledge.

Eirik Raanes is a very experienced lawyer and is able to value the issues on their merit and is therefore well able to focus on the issues that matter. He does this in a very relaxed and calm manner with a good sense of humour.

Magnus Greaker knows the issues very well and will go the extra mile for you. He is a no-nonsense person and will provide clear advice.

Professional, friendly, in-it-together feeling, at the same time arms-length distance in terms of providing advice.

Key clients


Samsung Electronics

Dagens Næringsliv AS

Ulstein ASA

BioMar Group AS


Orkla ASA

Eli Lilly and Company

Zimmer Biomet Norway AS

Welltec A/S

Enhanced Drilling AS

Telenor Digital AS

Equinor (formerly Statoil) ASA

Kongsberg Maritime AS

Krogh Optikk AS

Norgesgruppen ASA

Patogen Analyse AS

Rolex (Gros & Waltenspühl)

Intervet International BV (MSD)

Tetra Pak AB

Beerenberg Corp. AS

PatientSky AS

IFPI Norway

Nexans Norway AS/Nexans SA

Video Communications Services AS

Maritime law Tier 1

Mads Haavardsholm heads up the department at Advokatfirmaet Thommessen AS, which handles the full range of contentious and non-contentious shipping work for its client roster of ship owners, banks, rig owners and insurers. The practice also works closely with the firm’s banking and finance, insolvency, litigation and M&A teams to provide a cross-disciplinary service. The group’s core areas of expertise span charter parties and freight contracts, transactional work, vessel and rig sales and purchases, financing mandates and competition law. Stephen Knudtzon is a key name for contract law, insurance work and litigation; Olav Vikøren focuses on dry shipping matters, and Andreas Meidell and Henrik Hagberg are recommended for insurance-related mandates.

Practice head(s):

Key clients

Höegh Autoliners and Höegh LNG

Wilh Wilhelmsen Holding ASA

Gard AS

Offshore Heavy Transport AS

Forland Shipping AS

Island Offshore AS

Jo Tankers AS

Knutsen NYK Offshore Tankers ASA

Norwegian Hull Club

BW Maritime/BW Offshore/BW LPG

Team Tankers International Ltd.

Fearnley Advisors AS

TRF Ship Management AS

Clean Marine AS

Belships ASA

Kongsberg Gruppen ASA

Gdansk Shiprepair Yard “Remontowa” SA

Tschudi Shipping Company

Hunter Group ASA

Offshore construction and shipbuilding Tier 1

With ‘excellent negotiation and analytical skills’, Advokatfirmaet Thommessen AS acts for offshore yards, shipyards, EPC contractors, suppliers, shipowners, rig owners and oil and gas companies on a range of contentious and non-contentious mandates including restructurings, development projects, contractual issues and disputes. Noteworthy practitioners include construction project specialist Jacob F Bull, shipping practice head Mads Haavardsholm, Henrik Hagberg, who also assists with insurance work; and Pål Lieungh, who has experience handling international projects. Litigator Kristine Hyldmo Bjørnvik, who joined from Advokatfirmaet Haavind AS in 2019, made partner in early 2020.

Practice head(s):


Thommessen’s team has excellent negotiation and analytical skills. I can highly recommend them.

The group is pragmatic and to the point.

Pål Lieung is a very good negotiator – very convincing and able to find commercial solutions.

Jacob Bull is an excellent legal thinker.

Jacob Bull has a sharp legal mind, but with the ability to combine it with real life experience and industry knowledge.

Key clients

Equinor ASA (previously Statoil ASA)

Myklebust Verft

DNO International ASA

Island Offshore/Borgstein

RAK Petroleum PLC

Enhanced Drilling AS

Dong E&P A/S


Kongsberg Gruppen


Viken Shipping

Gdansk Shiprepair Yard “Remontowa” S.A.

Vard Group AS

Fearnley Advisors AS/Transportation Recovery Fund

Apollo Asset Ltd/Hunter Group ASA

Arne Blystad/Offshore Heavy Transportation

Qatar Navigation – Milaha

Connect LNG AS

Island Drilling AS

OHT Alfalift AS


Oil and gas Tier 1

Advokatfirmaet Thommessen AS excels across the full spectrum of oil and gas mandates including M&A, financing work, development projects and litigation. ‘Rising star in the oil and gas sectorChristian Hals leads the oil and gas team while ‘great negotiatorPål Lieungh heads up the oil services practice; Jacob F Bull is also singled out for his expertise in development projects, Mads Haavardsholm focuses on contract negotiations and transactions, Ståle R Kristiansen assists with tax-related matters, and Henrik Hagberg handles work in the oil services sector. Kristine Hyldmo Bjørnvik is also recommended for contentious work; she joined the firm in 2019 from Advokatfirmaet Haavind AS and made partner in 2020. The practice also notably strengthened its Stavanger offering in 2020 with the recruitment of Thomas Abrahamsen, Audun Stornes and newly promoted partner Jone Stakkestad from Kluge Advokatfirma AS.

Practice head(s):


Excellent client service and great quality advice. The firm is especially strong in oil and gas work in the energy sector and has an excellent track record. The team is very well informed on what is happening in the market and with regulators and other oil and gas stakeholders. Hands-on, client driven and very easy to work with.’

Thommessen’s team have excellent negotiation skills and are very analytical in their approach.’

They do not beat around the bush and they find solutions.’

Christian Hals is a rising star in the oil and gas sector. He is very pleasant to work with, dedicated and able to deliver top quality work at all times.’

Pål Lieungh is a great negotiator with a hands-on approach. He really is your true adviser.

I have worked extensively with Audun Stornes, Thomas Abrahamsen, and Jone Stakkestad. All three are first class oil and gas lawyers with excellent industry knowledge and work ethic. Availability, client engagement, and speed of response are top rate. Thomas specialises in oil and gas M&A work and is a highly effective negotiator; calm, logical and pragmatic, but very persistent when the situation requires it. Audun and Jone have a wider remit and provide well considered and effective advice across the oil and gas spectrum.

Key clients

BP International


Kongsberg Gruppen




Island Offshore

Faroe Petroleum

PGNiG Upstream Norway AS

Odfjell Drilling


Shelf Drilling


BW Offshore

RAK Petroleum

Circle K

EDS Group


MOL Norge


Myklebust Verft

TTC Norge AS

Veolia Environmental


Real estate Tier 1

With a team of ‘outstanding individuals’ who are ‘knowledgeable, accurate and well oriented in the market’, Advokatfirmaet Thommessen AS handles the full range of real estate issues and is noted for its transactional, development and project management expertise. The practice also has environmental law and contentious experience. Practice head Christopher Borch is praised by clients as ‘a bright lawyer who thinks outside the box’, the ‘always excellentChristian Müller specialises in property developments, and Even Bratsberg assists with real estate transactions and refinancing work. Vidar Havsgård is the key contact in Bergen.

Practice head(s):


Thommessen has outstanding individuals within all relevant real estate topics compared to its peers.

The team are always ready to help out – day and night!

The team is knowledgeable with quick and accurate responses, and is well oriented in the market.

Christian Müller and Chris Borch are both outstanding individuals, with in-depth knowledge in all real estate topics.’

Chris Borch is a bright lawyer with a lot of experience. Thinks outside the box.’

Mads Ole Haugen is a steady lawyer with deep experience.’

Christian Müller is excellent, always fast and provides reliable answers.

Key clients

Artic Securities AS

Clarksons Platou Real Estate AS

Nordic Real Estate Partners AS

Norwegian Property ASA

Oslo Areal AS

Starwood Capital Group

Watrium Eiendom AS

Promenaden Property AS

Scandinavian Property Group AS

Angelo Gordon

Meyer Bergman

Realkapital Investor AS

Oslo Airport City AS

Storebrand Eiendom AS

Søylen Eiendom AS

Industrifinans Capital AS

Kruse Smith Eiendom AS

Bulk Industrier AS

Mustad Eiendom AS

Geilo Holding AS


Glastad Farsund AS and Fortus AS

Vika Project Finance AS

Carucel Eiendom AS

Canica Eiendom AS

Eiendomshuset Malling & Co AS /Malling & Co Eiendomsfond AS

Tellus Eiendom AS

Tristan Capital Partners

Scandinavian Development Constructive Development AS

Orkla Eiendom AS

Neptune Properties AS

Norgesgruppen ASA

Tax Tier 1

Finn Backer-Grøndahl heads up the department at Advokatfirmaet Thommessen AS, which is recognised for its expertise in Norwegian corporate tax work, energy, petroleum and shipping tax regimes; indirect taxation, international work including tax treaties and transfer pricing mandates, and tax litigation. Backer-Grøndahl, Ståle R Kristiansen and Hanne Skaarberg Holen are key contacts for contentious work, Espen Ommedal handles international tax work for companies and private equity houses, Marius Holm Rynning leads the asset management group, and Bjørn Christian Lilletvedt Tovsen heads up the indirect tax practice.

Practice head(s):


Very professional and structured way of handling the court case. The team keeps the client well informed and presents the fair view of the probable outcome.

A team with strong industry knowledge, combined advisory and litigation experience, and with quality as a guiding principle in what they do.

Ståle Kristiansen is highly skilled and experienced in tax matters. He also understands our business and mind-set.’

Marius Holm Rynning is very skilled and very service minded.

Bjørn Christian Lilletvedt Tovsen is a very professional legal expert and well available for the client. His calm and professional approach to the case is highly appreciated.

The team members carry a spirit of confidence in their capabilities to the table, which also gives you a sense of their dedication to their work and client needs.

Key clients

Transocean Offshore Limited and Transocean Offshore International Ventures Limited


Orange Business Services AS

Ernst & Young

Fias Invest AS


Telenor ASA



Skatteklagenemnda (the Tax Appeal Board)

Odfjell SE

TMT Tier 1

Christopher Sparre-Enger Clausen, who ‘has a talent for finding commercial solutions’, leads the department at Advokatfirmaet Thommessen AS, which is singled out for its expertise handling IT and digital transformation projects. The practice is also highly active in the fintech, insurtech and medtech sectors, and is increasingly involved in GDPR and data protection matters alongside its work in the telecoms and media industries at a domestic and international level. Technology specialist Espen Werring receives praise for his ‘outstanding experience and track record’, associate partner Haakon Opperud focuses on IT projects, and Eirik W Raanes handles contentious mandates.

Other key lawyers:


Always solid and well-considered advice, highly responsive, full-service firm with ability to pull in the right resources when needed.

Thommessen’s TMT team offers very practical and hands-on advice, fields excellent teams with combined expertise, and shows outstanding business acumen.

Christopher Clausen is a strong partner, with a talent for finding commercial solutions to legal issues in a very regulated environment.

Espen Werring is highly professional, proactive and has deep knowledge of the areas of transformation, transition and outsourcing work.

I want to call out Christopher Sparre-Enger Clausen in particular, but the entire team is excellent from my experience working with them for many years. Christopher is very agile and business-oriented, has a wealth of knowledge, provides practical advice that’s easily digestible to the business client and is highly responsive.

Key clients

Microsoft Corporation (including its Norwegian subsidiary, Microsoft Norge AS)

Vipps AS

Hafslund Nett AS

Wilh. Wilhelmsen ASA

The Council on Ethics for the Norwegian Government Pension Fund Global

The Association of the Pharmaceutical industry in Norway (LMI)/NomVec AS

Yara International

Lyse Energi AS including its subsidiaries Altibox and Smartly

NHST Media Group AS (Dagens Næringsliv)

Zalaris ASA

Construction Tier 2

Advokatfirmaet Thommessen AS leverages its ‘very knowledgeable and diligent’ team to advise on large development and construction projects in the renewable energy, infrastructure and transport sectors. The group is currently advising NorthConnect on the proposed establishment of a high-voltage direct-current interconnector between Norway and the UK and is assisting Mustad Eiendom with a property development project in Lilleaker. Jacob F Bull leads the practice, which also includes litigator Svein Aage Valen in the firm’s Bergen office. Asle Bjelland is now a judge.

Practice head(s):


The Thommessen team are very knowledgeable and diligent. They are fast working and always to the point. They have remarkable knowledge in technical matters and quite often ask critical questions in meetings. Their extensive experience in construction contract work has in many instances avoided legal disputes.

Very client-oriented. Understands clients needs.

Kristine Hyldmo is perceptive and delivers well. Jacob Bull always has a solid, well thought through and efficient way of providing advice.

Fast working, always available, knowledgeable and very friendly.

Key clients

NorthConnect KS

Zephyr AS

Lyse Produksjon AS

Midtfjellet Vindpark AS.

Eidsiva Energi AS

Sira-Kvina Kraftselskap DA

Watrium Eiendom AS

Yara International ASA

Hordaland Fylkeskommune


Universitetet i Bergen

K21 Holding AS

Neptune Properties AS

Mustad Eiendom AS

Statens Vegvesen (Norwegian Public Road Authorities)

Agder OPS Vegselskap AS

Arbaflame AS

Austri Vind


Thommessen is one of Norway’s leading commercial law firms, with offices in Oslo, Bergen, Stavanger and London. Since our foundation in 1856, we have been closely involved in most of the defining developments in Norwegian business. Our clients are Norwegian and international businesses, in both the private and public sector.

At Thommessen, we enable our clients to achieve their objectives by understanding their challenges and opportunities. Our advice is clear, well-founded and practically oriented, and is premised on in-depth understanding of the factors affecting the interests of our clients, whether commercial, technological, societal, political or global.

Earning trust
Our business is built on trust. We repay that trust by how we relate to each other, our clients, our business partners and other parties. In a rapidly changing world, we are focused on understanding our clients and tailoring our services to their needs. We earn trust.

Department Name Email Telephone
Managing Partner Sverre Tyrhaug +4723111330
Asset Management Marius Holm Rynning +4723111387
Banking and financing Ellen Teresa Heyerdahl +4723111329
Compliance and investigations Hugo-A. B. Munthe-Kaas +4723111127
Construction Jacob F Bull +4723111156
Data protection and cyber security Christopher Sparre-Enger Clausen +4723111141
Debt capital markets Einar Grette +4723111220
Dispute resolution Kristine Hyldmo Bjørnvik +4723111035
Employment Stein Kimsås-Otterbech +4723111174
Equity capital markets Solveig F Bugge +4723111199
EU/EEA and competition Siri Teigum +4723111121
Financial regulation Tore Mydske +4723111252
FinTech Christopher Sparre-Enger Clausen +4723111141
Fishery and aquaculture Mons Alfred Paulsen +4755306142
Insolvency and restructuring Kristoffer Hegdahl +4723111308
Insurance Andreas Meidell +4723111304
Intellectual property and marketing law Camilla Vislie +4723111178
Life sciences and health care Magnus Hauge Greaker +4723111147
M&A Christian Grüner Sagstad +4723111328
Oil and gas Christian Hals +4723111096
Oil service Pål Lieungh +4723111112
Private equity Christian Grüner Sagstad +4723111328
PropTech Christopher Sparre-Enger Clausen +4723111141
Public Procurement Eivind J Vesterkjær +4723111123
Real estate Christian Müller +4723111101
Renewable energy and infrastructure Jens Naas-Bibow +4723111362
Retail Eivind J Vesterkjær +4723111123
Shipping Mads Haavardsholm +4723111242
Sustainability and climate risk Tore Mydske +4723111252
Tax and duties Finn Backer-Grøndahl +4723111103
Technology and digitalisation Espen A Werring +4723111493
Venture capital Ylva B. Gjesdahl Petersen +4723111105
Photo Name Position Profile
Mr Hans Cappelen Arnesen  photo Mr Hans Cappelen Arnesen Mr Hans Cappelen Arnesen (“Hasse”) works primarily with matters concerning M&A, offerings…
Mr Anders Arnkværn  photo Mr Anders Arnkværn Partner. Mr Anders Arnkværn has long experience within the areas of M&A…
Mr Ervin Auren  photo Mr Ervin Auren Partner. Mr Ervin Auren works primarly with mergers, acquisitions and capital market…
 Finn Backer-Grøndahl photo Finn Backer-Grøndahl Partner. Mr Finn Backer-Grøndahl works with both national and international tax law…
Mr Baard Bale  photo Mr Baard Bale Partner. Mr Baard Bale focuses on, and has significant experience with, equity…
Mr Stig Berge  photo Mr Stig Berge Partner. Mr Stig Berge is one of Norway’s leading lawyers within corporate…
 Kristine Hyldmo Bjørnvik photo Kristine Hyldmo Bjørnvik Partner. Kristine mainly works with dispute resolution with a particular focus on…
Mr Christopher Borch  photo Mr Christopher Borch Partner. Mr Chris Borch mainly works with purchase and sale, development, leasing,…
Mr Even Bratsberg  photo Mr Even Bratsberg Partner. Mr Even Bratsberg has twenty years of experience as lawyer in…
Mrs Solveig Fagerheim Bugge  photo Mrs Solveig Fagerheim Bugge Partner. Mrs Solveig Fagerheim Bugge has extensive experience with M&A and capital…
Mr Jacob F Bull  photo Mr Jacob F Bull Mr Bull’s work mainly relates to offshore and onshore construction projects within…
Mr Bendik Christoffersen  photo Mr Bendik Christoffersen Mr Christoffersen works with matters concerning renewable energy and focuses on concession…
Mr Tron Dalheim  photo Mr Tron Dalheim Tron is a recognized employment law adviser to Norwegian and international companies.…
Mrs Ylva Gjesdahl Petersen  photo Mrs Ylva Gjesdahl Petersen Ylva works with equity capital market transactions and M&A across various industries,…
Mr Einar Grette  photo Mr Einar Grette Mr Einar Grette’s practice focuses on financing and restructuring in the bank-…
Mr Mads Haavardsholm  photo Mr Mads Haavardsholm Mr Haavardsholm works primarily with contract negotiations and transactions towards clients in…
Mr Henrik Hagberg  photo Mr Henrik Hagberg Partner. Mr Henrik Hagberg has broad experience from working with both contentious…
Mr Christian Hals  photo Mr Christian Hals Partner. Christian works primarily with M&A and securities law within the oil…
Mr Henning Harborg  photo Mr Henning Harborg Mr Harborg assists clients from a wide range of business areas with…
Mr Magnus Hauge Greaker  photo Mr Magnus Hauge Greaker Managing Associate Magnus mainly works with patent, trademark and trade secrets litigation,…
Mr Hans Haugstad  photo Mr Hans Haugstad Mr Hans Haugstad predominantly works with financing transactions and assists both banks/financial…
Mr Kristoffer Hegdahl  photo Mr Kristoffer Hegdahl Partner. Kristoffer has extensive experience from domestic and cross-border financing transactions, acting…
Mrs Ellen Teresa Heyerdahl  photo Mrs Ellen Teresa Heyerdahl Partner. Mrs Ellen Teresa Heyerdahl has extensive experience with financing. She assists…
Mrs Heidi Jorkjend  photo Mrs Heidi Jorkjend Managing Associate Heidi works with competition law and marketing law. She has…
 Stein Kimsås-Otterbech photo Stein Kimsås-Otterbech Mr Stein Kimsås-Otterbech has extensive experience with matters concerning employment law and…
Mr Stephen Knudtzon  photo Mr Stephen Knudtzon Mr Knudtzon’s practice includes legal advice with emphasis on maritime and oil…
Mr Ståle R Kristiansen  photo Mr Ståle R Kristiansen Mr Kristiansen advises several major Norwegian and foreign companies in connection with…
 Pål Lieungh photo Pål Lieungh Mr Lieungh has many years of experience as legal advisor within the…
Mr Halvor Mansåker  photo Mr Halvor Mansåker Mr Mansåker works primarily with debt capital market transactions, assisting both managers…
Mr Gunnar Martinsen  photo Mr Gunnar Martinsen A significant part of Mr Martinsen’s work is related to the conditions…
Mr Andreas Meidell  photo Mr Andreas Meidell Mr Meidell works mainly on commercial insurance claims and coverage issues, such…
Mr Øyvind Mork Karlsen  photo Mr Øyvind Mork Karlsen Managing Associate. Øyvind has long experience within Mergers & Acquisitions, and acts…
 Christian Müller photo Christian Müller Mr Müller has been involved in a large number of the most…
Mr Tore Mydske  photo Mr Tore Mydske Mr Mydske advises financial companies with what is considered as regulated activity…
Mr Reidar Myhre  photo Mr Reidar Myhre Associate Partner. In recent years, Mr Myhre has been involved in several…
Mr Jens Naas-Bibow  photo Mr Jens Naas-Bibow Mr Naas-Bibow deals with matters concerning energy law, environmental law and litigation.…
Mrs Ingrid Cathrine Nielsen  photo Mrs Ingrid Cathrine Nielsen Managing Associate Ingrid Cathrine advises both Norwegian and international clients within all…
Mr Lars Eirik Gåseide Røsås  photo Mr Lars Eirik Gåseide Røsås Partner. Mr Lars Eirik Gåseide Røsås advises a number of listed companies…
Mr Eirik W Raanes  photo Mr Eirik W Raanes Mr Raanes works primarily with dispute resolution within contract law, construction law,…
Mr Marius Holm Rynning  photo Mr Marius Holm Rynning Partner. Mr Marius Holm Rynning primarily works with tax law and corporate…
Mr Eivind Sæveraas  photo Mr Eivind Sæveraas Associate Partner. Mr Sæveraas is primarily recognised for his work on several…
Mr Christian Grüner Sagstad  photo Mr Christian Grüner Sagstad Head of M&A and Corporate law department, Partner. Mr Christian Grüner Sagstad,…
Mr Christopher Sparre-Enger Clausen  photo Mr Christopher Sparre-Enger Clausen Partner. Christopher heads Thommessen’s Technology and Data Protection practice group and specialises…
Mrs Siri Teigum  photo Mrs Siri Teigum Mrs Teigum acts as an advisor and litigator in procurement matters, and…
 Bjørn Christian Lilletvedt Tovsen photo Bjørn Christian Lilletvedt Tovsen 2018-current Partner, Oslo office, Thommessen; 2015-2017 Managing Associate, Oslo office, Thommessen; 2012-2014 Senior…
Mr Sverre Tyrhaug  photo Mr Sverre Tyrhaug Managing Partner. Mr Sverre Tyrhaug has advised on a number of share…
Mr Svein Aage Valen  photo Mr Svein Aage Valen Mr Valen has litigated numerous cases before both the public courts and…
Mr Eivind J Vesterkjær  photo Mr Eivind J Vesterkjær Mr Vesterkjær’s practice focuses on matters relating to competition law, public procurement…
Mr Olav Vikøren  photo Mr Olav Vikøren Mr Vikøren has extensive experience assisting a wide range of players in…
Ms Camilla Vislie photo Ms Camilla Vislie Mrs Vislie heads Thommessen’s IP and Technology practice. She works mainly with…
Mr Espen Werring  photo Mr Espen Werring Espen is a trusted adviser to organizations developing and implementing their mission-critical…
Number of lawyers : 195
at this office : 160
Norwegian Bar Association
Lex Mundi
Contact : Sverre Tyrhaug, managing partner (
Other offices : Bergen
Other offices : Stavanger
Other offices : London


A large and ever-expanding share of our activities are international in nature. We represent non-Norwegian businesses in Norway, as well as Norwegian businesses internationally, and have acted in some of the largest cross-border matters into and out of Norway in recent years. We have an office in London and an extensive network of international partners.


Our lawyers have extensive international experience. This stems not only from the many international and cross-border matters that we handle, including litigation before international, courts, but also from work, secondment and studying abroad.

Our experience and recognition enables us to work well with different international players. We are familiar with cultural diversities and standards, hence we are able to find the best solutions for our clients, also abroad. Thus, we are well placed to seamlessly obtain legal advice from foreign counsel in multi-jurisdictional projects or incidents.


Thommessen’s London office is headed by Resident Partner Lars Eirik Gåseide Røsås, and has served as an important international market gateway for more than three decades. A large portion of our lawyers have been on secondments to our London office to gain international experience.

Our London team have comprehensive experience in cross-border transactions, and Thommessen’s lawyers have argued numerous cases before international courts and tribunals.


We are the Norwegian member of Lex Mundi; the world’s leading network of independent law firms. Membership provides valuable cross-border knowledge sharing, as well as direct access to leading law firms worldwide – for both us and our clients.

We also have an extensive non-exclusive personal network enabling us to use other partners depending on the case at hand and the requirements of our clients.


Thommessen is perhaps best known for its handling of large and complex public and private M&A work and capital market transactions, involving multiple jurisdictions and often in combination with equity issues and debt financing of the transaction.