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Key practice areas
Intellectual property
Trade mark
Patent
Firm overview

Onsagers AS is the leading IP Law- and IP Management Consulting firm in Norway, with nearly 80 years of expertise and global perspective. With close to 100 employees in Norway and key international locations, we offer comprehensive services and strategic advice across the entire intellectual assets value chain, thoughtfully aligned with our client’s objectives and business strategies.

Operating from offices in Oslo, Tromsø, and Bergen, as well as branches in Sweden, Germany, and the UK, Onsagers has firmly established itself as the market leader in the Norwegian IP landscape, with plans for further expansion in the Nordics and across Europe. Our extensive network and partnerships with top-tier IP firms worldwide attest to our global reach and collaborative approach.

Team of international IP experts in Norway

Onsagers’ dedicated team of experts is comprised of Attorneys at law and European patent attorneys with extensive international and technical expertise. We work closely in industry teams allowing us to focus on the clients’ business and understanding the complex technological and legal landscape in which they operate. Our main focus remains to deliver holistic IP advice of the highest quality, tailored to meet the diverse needs of our clients.

Our team of experts has comprehensive experience in IP management, IP strategy, IP transactions, trademark-, design and patent prosecution, enforcement and litigation, including customs seizures, passing-off and unfair competition cases, as well as trademark, design and patent infringement and validity cases, some of which have attracted international attention. With experience from the Norwegian Industrial Property Office (NIPO), the Appeal Board as well as representing Norway at WIPO and the EPO, in addition to experience as in-house counsel and litigation experience from private law firms, our team ensures updated insight to Norwegian IP practice, offering informed advice and strategic solutions for safeguarding the clients’ IP.

At Onsagers, the foundation for our well-established practice is our focus on high professional quality and excellent service and integrity for our clients. Our objective is to be your trusted partner for the protection, management, exploitation, and enforcement of your IP, offering clear, cost-effective advice backed by modern technology and forward-thinking approach.

Network Memberships

INTA, ECTA, MARQUES, EPI, NPF, FICPI, TEKNA, I3PM, SIPF, SFIR, AIPPI, NIR, LES

Practice Areas & Sector Specialisations

Key Sector Expertise

  • Aerospace & Defence
  • Automotive
  • Construction & Materials
  • Engineering
  • Fashion & Luxury Goods
  • Food & Beverage
  • Furniture
  • Green Technology
  • ICT & Software
  • Instruments
  • Life Sciences & Chemistry
  • Manufacturing
  • Medical Devices
  • Optics & Photonics
  • Pharmaceuticals
  • Robotics & Nanotechnology
  • Telecommunication
Address:
Munkedamsveien 35
Oslo
0250
Tel:+47 95 16 38 86 Email:Contact Us Web Address:http://onsagers.com
2026 Edition
Patent prosecution
Highly Recommended
5 firms ranked
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Overview

IP firms Acapo and Onsagers merged in 2025 to form Acapo Onsagers.

Acapo

Acapo was previously reanked for its IP protection and portfolio management work. The firm's patent attorneys have expertise in physics, mechanics, electronics, and telecommunications.

Notable patent practitioners: Hilde Vold-Burgess, Gunnar Nilsen Søndersrød, Trond Øvsttun, Børge Andre Hilden, and Stein Roar Gjøen.

Onsagers

Onsagers was highly rated for IP protection and portfolio management work. The firm had a large team of patent attorneys covering technical fields such as chemistry, life sciences, and engineering. Some of the attorneys previously worked for the Norwegian IP Office, and they are active in patent litigation support work. The firm also had a team for trade mark protection, IP disputes and IP-related transactions. 

Notable patent practitioners: Lars-Fredrik Urang, Anette Robsahm Røhmen, Dorte Lajer, Kim Livgard and Kari Helen Simonsen. 

Notable soft IP practitioners: Edmund Andre Høydahl, Eirik Rødsand, Kristoffer Weltzien, Christiin Sangvik-Jebsen, Thomas Gaarder-Olsen, Ann-Cathrin Hoel, and Ulrikke Asbøll. 

Testimonials

2025

Acapo

"Great service, quality work, fast turnaround."

"Responsive team, made a plan for delivery and delivered on time and on budget. Good discussions with the team."

"They have always delivered quality, and we are happy and confident to use [them]."

"Reliance and competence."

"They are professional and experienced and take ownership and pride in their work."

"Continuity and skilled people, structured meetings and good follow-up on cases. Excellent service."

 

Onsagers

"Highest skill and knowledge level, prompt responses, and reasonable rates."

"We have worked together with Onsagers for many years, and we have a very good collaboration."

"Onsagers has a strong, big team, with several great lawyers who can represent clients throughout."

"Good firm with strong trademark portfolio competence."

"Onsagers has proven to be a trusted and reliable partner, and we now collaborate on various matters.

"Their professionalism, along with their technical knowledge, particularly in handling complex patent cases, including those involving AI-related technologies, makes them an excellent choice for such work."

"Alert, always answering quickly and advising well."

"Onsagers communicate very well, and they provide clear guidance and recommendations. The team at Onsagers is very organised and has great attention to detail."

"The team is very proactive, positive and nice to work with. They are very skilled and knowledgeable about EPO case law."

"Knowledgeable people that are pleasant to work with."

"We greatly appreciate Onsager’s technical expertise and reliability. Their team, particularly our close collaborations with Eirik Rødsand and, more recently, Pernille Rekdal in trademark cases, has been excellent."

[They give] us confidence that they can handle a wide range of IP challenges."

"Excellent, hands-on, and skilful."

"We chose Onsagers AS for their strong reputation in IP matters, deep understanding of the Norwegian market, and their practical, business-focused approach to trademark prosecution."

"Experienced, professional, solution-oriented, and agile."

"We appreciate Onsagers’s IP team for their expertise, responsiveness, and strategic mindset. They provide clear, well-structured advice and handle trademark matters efficiently and professionally."

Kari Simonsen

"They, and in particular Kari Simonsen, have been the preferred partner for assistance in pharmaceutical patent litigation since 2001."

Eirik Rødsand

"Onsagers and especially Mr. Rødsand has a unique and holistic approach to IP and is especially good at making the most out of clients' IP budgets."

 

Onsagers

2024

"We have worked with Kari Simonsen for many years, and she is one of the best patent attorneys within the field of pharmaceuticals in Norway. They are proactive, knowledgeable and positive to work with."

"The best assistance we can get in pharma patent litigation. We like them because of their high skills, pleasant to work with, they know what we need, and are proactive."

"I have a longstanding close working relationship with several IP lawyers at Onsagers whom I trust completely. They have incredible knowledge, expertise, and responsiveness."

"They are the best in the Norwegian market. Period. They are quick, efficient, and cost-effective."

Kari Simonsen

"She is proactive, knowledgeable and nice to work with. She is one of the best patent attorneys within pharmaceuticals in Norway."

"Extremely knowledgeable in chemistry/biology, very pleasant to work with."

Eirik Rødsand

"Works on trademark prosecution, contentious matters, strategic advice."

Ulrikke Asbøll

"Works on trademark prosecution and portfolio management."

Christiin Sangvik-Jebsen

"She is very professional, knowledgeable and friendly."

2023

"The team were flexible and able to act at short notice."

"Onsagers' communication is second to none. They lay out all of the major issues in a matter in an easy-to-digest way that makes my job as IP counsel significantly easier. In particular, Martha Borge stands out as an incredible attorney."

"Onsagers provide their honest opinion and are always available. Our key account manager Per Reiner and his colleagues are highly appreciated."

"They know what I expect and how I like to receive their recommendations. "

"They understand how we work and adjust to our procedures."

"They are efficient and with a good combination of technical understanding and IP/patent capabilities."

"They are easy to work with, service-minded and have excellent expertise."

"They are such great people and always understand what we (or our clients) need from the start."

"They are very competent, responsive, proactive, positive and nice to work with."

"We appreciate their down-to-earth attitude along with their excellent legal skills."

 

Acapo

2023

"They understand our work or business, and provide good advice. They always take the time to explain the legal implications in a way that is understandable for someone without legal background. I always feel heard and understood and don't have to worry about asking questions and letting them know when I don't understand. We are a Norwegian company with products being distributed digitally all over the world, so we have complicated cases and they have knowledge about different rules and requirements in all the regions of the world where we distribute. "

"They are a skilled and friendly team who expand our horizon on patents and get the job done."

"They are professional, fast and reliable."

"They are diligent, responsive, knowledgeable and pragmatic."

"Personal and dedicated approach, cost-effective and service-minded."

2022

"They respond quickly with precise legal advice."

"They know what they are doing in IP."

"They have the ability to think broad and widen scope of coverage."

"Always easy to reach, and they provide prompt feedback and guidance. Even though our industry was not that known to them, they quickly learned and acquired the necessary knowledge about our products and services."

"We have been using Acapo as our advisors for IP-related concerns for many years and have good experience and relations with them. In our view, they are very good in their area of expertise and give outstanding service to their customers."

Linked Reviews
Patent

Case studies show patent protection, portfolio management, and office proceedings work in different technical fields. The firm also advised on patent disputes. European patent attorneys Joe Henderson, Sebastian Vincent and Ben Lawrence joined the firm in 2024. Patent attorneys Liv-Heidi Thorsen, Svein Stenbek and Elen M Brendeford have left the firm.

Trade mark

Case studies show trade mark clearance, filing, litigation and office proceedings. Clients include Aquabyte. Anders Solberg and Fredrik Almaas left the firm in 2024.

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