| NSP Invest AS | | 2026 |
| Nussura Eiendom AS | Real estate | 2021 |
| Nyheim Rammer AS | Manufacturing | 2023 |
| Nyland Studentbarnehage AS | Education | 2022 |
| Nymo Kapital AS | | 2026 |
| Nymoe Eiendom AS | Real estate | 2021 |
| Nymoe Elektro AS | Construction | 2004 |
| Nyvoll Holding AS | | 2019 |
| Nyvoll Maskin AS | Construction | 2012 |
| Nåa Lås AS | Wholesale & retail | 2020 |
| O M Eiendom AS | Real estate | 2010 |
| O.H Holding AS | Administrative & support | 2025 |
| O.Kivijervi AS | Professional & scientific | 2018 |
| O.Kivijervi Holding AS | Professional & scientific | 2018 |
| O2 Eiendom Alta AS | Real estate | 2015 |
| O2 Gruppen AS | Construction | 2024 |
| Ocean Orakel Service AS | Professional & scientific | 2024 |
| Odd Mathisen AS | Construction | 1998 |
| Odd Mathisen Eiendom Ans | Real estate | 2001 |
| Oddbjørn Thomassen AS | Construction | 2009 |
| Offroad Finnmark AS | Arts & recreation | 2008 |
| Offshore Team AS | Administrative & support | 2019 |
| Oh Johansen AS | Agriculture & fishing | 2022 |
| Oit Holding AS | | 2022 |
| Oj Fisk AS | Agriculture & fishing | 2024 |
| Ojh Eiendom AS | Construction | 2016 |
| Ojh Holding AS | Construction | 2016 |
| Ok Takst & Bygg AS | Real estate | 2022 |
| Ola Bromseth AS | Health & social care | 2022 |
| Ole F Suhr AS | Construction | 2011 |
| Ole Jonny AS | Agriculture & fishing | 2024 |
| Ole Wilhelmsen AS | Administrative & support | 2023 |
| Ole Østlyngen AS | Real estate | 2001 |
| Oleif Simensen Transport AS | Transport & logistics | 1999 |
| Olsen Kran AS | Transport & logistics | 2020 |
| Olsen Og Thomassen Holding AS | | 2018 |
| Om Kran AS | Administrative & support | 2017 |
| Omthomassen Holding AS | Real estate | 2023 |
| Omthomassen Maskin AS | Construction | 2023 |
| Onga AS | Hospitality | 2020 |
| Onnest AS | | 2025 |
| Opgård Gruppen AS | Construction | 2022 |
| Opgård Maskin AS | Mining & quarrying | 1990 |
| Oppgjør Nord AS | Administrative & support | 2021 |
| Opplæringskontor for Transport Og Logistikk Finnmark SA | Education | 2017 |
| Opptur Invest AS | Real estate | 2010 |
| Optimedia AS | Professional & scientific | 2023 |
| Origo Kapital AS | Energy | 1999 |
| Orinor AS | Professional & scientific | 2001 |
| Orion Eiendom Alta AS | Real estate | 2009 |
| Orus Moments AS | Administrative & support | 2019 |
| Oskarsson Transport AS | Construction | 2018 |
| Osteopat Elisabet AS | Health & social care | 2020 |
| Osteopat Marianne Johansen AS | Health & social care | 2022 |
| Osteopatiklinikk Alta AS | Health & social care | 2012 |
| Osteopatisk Klinikk AS | Health & social care | 2014 |
| Ottem Kontor AS | Real estate | 2019 |
| Ottemgården AS | Real estate | 2016 |
| P & a Eiendom AS | Construction | 2012 |
| P & a Holding Alta AS | Construction | 2020 |
| P R E Invest AS | Financial services | 2015 |
| P. Nilsen Invest AS | Financial services | 2018 |
| P.A. Holding AS | | 2021 |
| Pa Maling AS | Construction | 2014 |
| Pacifique Tannlege AS | Health & social care | 2023 |
| Pactec AS | Wholesale & retail | 2020 |
| Pallefabrikken Alta AS | Manufacturing | 2025 |
| Panzer Norge AS | Professional & scientific | 2018 |
| Papela AS | Manufacturing | 2022 |
| Paranord Film AS | Information & communication | 2014 |
| Park & Anlegg Alta AS | Construction | 2015 |
| Park Eiendom AS | Real estate | 1996 |
| Parkbo AS | Real estate | 1997 |
| Parkbo Eiendom AS | Real estate | 2026 |
| Parken Eiendom AS | Real estate | 2022 |
| Parken Solutions AS | Construction | 2022 |
| Parken Solutions Holding AS | Mining & quarrying | 2022 |
| Partrederiet Boysen Da | Agriculture & fishing | 2015 |
| Paul Stene AS | Transport & logistics | 1994 |
| Paulsen Drift AS | Construction | 2020 |
| Paulsen-Holding AS | Professional & scientific | 2018 |
| Pedersen Betongsaging AS | Construction | 2006 |
| Pedersen Maskin AS | Construction | 1989 |
| Pedersen Maskin Eiendom AS | Real estate | 2021 |
| Pedersens Varmeservice AS | Wholesale & retail | 2002 |
| Per Vidar Andersen AS | Health & social care | 2012 |
| Per-Espen Holding AS | | 2022 |
| Perfecthair AS | Other services | 2017 |
| Personell AS | Administrative & support | 2017 |
| Personell Entreprise AS | Construction | 2022 |
| Peter Fogg AS | Agriculture & fishing | 2021 |
| Pettersen-Bygg AS | Construction | 2023 |
| Peyma Eiendom AS | Construction | 2013 |
| Peyma Entreprenør AS | Construction | 2013 |
| Peyma Holding AS | Construction | 2022 |
| PF Utvikling AS | Real estate | 2023 |
| Pga Holding AS | Professional & scientific | 2019 |
| Pioner Invest AS | | 2024 |
| Pirasmussen Holding AS | | 2022 |
| Pit Holding AS | Administrative & support | 2021 |