Jan B. Jansen > BAHR > Oslo, Norway > Lawyer Profile

0117 OSLO

Work Department

Dispute Resolution




Jan B. Jansen is a prominent and respected lawyer, who specializes in dispute resolution, tax and insurance law, as well as the oil and energy sector.
Jan has worked closely with oil and energy since 1986 and has acted for his clients in many capacities: such as advisor on regulatory matters and transactions, and as counsel in litigation. His clients include many of the largest companies active on the Norwegian Continental Shelf, as well as the Norwegian State. Jan has a thorough understanding of the oil and gas business and the challenges facing the actors involved. He has represented most of the large E&P companies in tax litigation and has successfully pleaded many of the most notable tax cases for the industry.
Additionally, Jan has represented a number of law firms in professional indemnity claim cases. He also assists on insurance matters, where he advises insurance companies on policy issues and claims handling, and represents them in insurance and reinsurance disputes.
As a litigator, Jan acts on a large variety of commercial cases before the courts and arbitral tribunals. He is also sought-after as arbitrator. For many years, he taught General Tax Law and Petroleum Tax Law at the University of Oslo.
Jan was admitted to the Supreme Court in 1997 and has since pleaded numerous landmark cases.
He is head of the Norwegian Bar Association’s Legislative Policy Committee for Energy, Hydropower, Oil and Gas law.


1997 – Admitted to the Supreme Court

1984 – Cand. jur, University of Oslo

Lawyer Rankings

Norway > Insurance

BAHR fields a full-service and insurer-focused practice that is ‘approachable, commercially aware, swift and accurate’. The team advises both domestic and international clients, and has particular expertise in marine insurance, regulatory work and asset management issues. Practice head Jan Jansen regularly acts for insurers in complex professional liability claims. Atle Skaldebø-Rød is a ‘fantastic‘ contact for marine insurance litigation who regularly advises maritime and offshore insurance providers, as does fellow marine insurance expert Tarjei Thorkildsen, while Eirik Høiby is an energy and offshore specialist. Marte Leveraas is another key member of the marine insurance team, while Mads Schjølberg, who is an ‘excellent litigator‘, has a wide-ranging practice in insurance, with particular expertise in international matters.

Norway > Dispute resolution

(Hall of Fame)

Jan JansenBAHR

The ‘high-quality’ disputes team at BAHR has extensive expertise across all areas of commercial litigation, regularly handling high-value M&A disputes, contentious insolvency matters, and shareholder disputes for an impressive roster of clients. Combining ‘expert‘ litigators with subject-matter specialists across Norway’s biggest industries, the team attracts praise for its interdisciplinary work, a core pillar of the practice. The group has also seen a recent increase in cases concerning professional liability. Atle Skaldebø-Rød heads up the team and has a broad contentious practice, while Jan Jansen is renowned for his tax litigation expertise. Another key name here is Simen Skjold Søgaard, who is also recommended for competition law matters. Thomas K. Svensen handles energy sector litigation and arbitration, while Sam E. Harris takes point on construction and real estate-related disputes. Sofie Komissar left the firm in March 2023.

Norway > Energy

(Hall of fame: Oil and gas)

Jan JansenBAHR

Attracting praise for its ‘profound understanding of the oil and gas business’, BAHR maintains a market-leading transactional offering across the full range of energy sectors, handling high-value and complex consolidations, acquisitions, and cross-border M&A for leading industry players. Managing partner Thomas K. Svensen focuses his practice on oil and gas work, Stig Klausen Engelhart leads on petroleum law mandates, and the ‘deeply experiencedJon Christian Thaulow oversees the energy and environmental law group; the trio jointly lead the firm’s energy practice. Other core names to note include Rune Svoren, who is highly recommended for his expertise in electricity transactions, tax and litigation specialist Jan Jansen, and Trond Lingaas, who handles regulatory and contractual issues in the oil and gas industry. Jens Naas-Bibow joined the practice from 1,5 Advokatfirma AS in early 2024.

Norway > Tax

The ‘impressive‘ tax practice at BAHR assists with a wide range of tax-related issues, including corporate tax work, complaints and transfer pricing matters, and has ‘excellent sector knowledge‘ of the oil, energy, shipping, real estate and private equity spaces. Practice head Joachim Bjerke is a ‘first-class tax lawyer‘ who focuses on international tax work, transfer pricing issues and structuring M&A transactions. The group also includes real estate tax expert Anne Sofie Bjørkholt, litigator Jan Jansen, who is an authority on the special petroleum tax regime; and ‘excellent adviser and litigatorSimen Skjold Søgaard. Peter Hammerich and Camilla Jøtun both advise on tax work relating to asset management and private equity issues. Other notable practitioners are Helge Olav Bugge, who handles tax disputes and matters relating to the special tax regime for hydro power, and VAT specialist Camilla Hammer Solheim. Nils Flesland Bull and Knut Ekern joined the practice in early 2024 from Harboe & Co AS.