| Norwegian Bedrock Group Nuf | Professional & scientific | 2017 |
| Note AS | Financial services | 2005 |
| Nothusbukta AS | Real estate | 2022 |
| NPV Invest AS | Real estate | 2012 |
| Nru Holding AS | Information & communication | 2018 |
| Ny Eigedom AS | Real estate | 2007 |
| Ny Sti AS | Wholesale & retail | 2018 |
| Nybrå Agentur AS | Wholesale & retail | 2001 |
| Nyhamna AS | Wholesale & retail | 2026 |
| Nysnø AS | Financial services | 2015 |
| Norsk Landbrukskjemi AS | Financial services | 1987 |
| Næringsinvest Møre Og Romsdal AS | Real estate | 2009 |
| Nøffe Holding AS | | 2025 |
| Nøisomhed AS | Real estate | 1996 |
| Nøisomhed Gård AS | Real estate | 2017 |
| Nøisomhedvegen 19 AS | Real estate | 2019 |
| Nøtskaret Eiendom AS | Real estate | 2017 |
| O a Sanne AS | Construction | 1982 |
| O E Strande AS | Wholesale & retail | 1968 |
| O F Group AS | Wholesale & retail | 2024 |
| O Øverland AS | Wholesale & retail | 1968 |
| O.E Midthaug AS | Professional & scientific | 2023 |
| Oa Langset AS | Professional & scientific | 2005 |
| Oaser Holding AS | Financial services | 2015 |
| Ober 74 AS | Real estate | 2026 |
| Oceanic Invest AS | | 1998 |
| Odd Fellow Huset Molde AS | Real estate | 1996 |
| Oddi Invest AS | | 1994 |
| Oddmund Langset AS | | 2020 |
| Oddvar Johnsen. AS | Professional & scientific | 2009 |
| Odss AS | Manufacturing | 2005 |
| Oge Holding AS | | 2026 |
| OIL24 AS | Wholesale & retail | 2010 |
| Ojvs Management AS | Professional & scientific | 2024 |
| Okv Invest AS | Real estate | 2013 |
| Olav 5TH Invest AS | | 2025 |
| Olav Berge Produksjoner AS | Professional & scientific | 2022 |
| Olav Sandvik AS | Real estate | 1964 |
| Ole Erik Berg Holding AS | Financial services | 2008 |
| Olsens Møbler AS | Manufacturing | 1998 |
| Oma Invest AS | Financial services | 2010 |
| Omav AS | Construction | 2024 |
| Omigo AS | Professional & scientific | 2022 |
| On Linje AS | Construction | 2018 |
| One Win AS | Real estate | 1996 |
| Ooops AS | Financial services | 2017 |
| Oppdal Eiendomsforvaltning AS | Administrative & support | 2025 |
| Oppkok AS | Other services | 2025 |
| Opptur MFK AS | Professional & scientific | 2005 |
| Optibygg AS | Construction | 2026 |
| Orera AS | | 2025 |
| Orivo AS | Professional & scientific | 2013 |
| Ormbostad Eiendom AS | Real estate | 2018 |
| Orrem Holding AS | | 2025 |
| Orrem Taxi AS | Transport & logistics | 2025 |
| Osare Holding AS | | 2021 |
| Oscarsborr Holding AS | Real estate | 2005 |
| Osek AS | Professional & scientific | 2021 |
| Osenvassdraget Fiskelag SA | Real estate | 2024 |
| Oshaug AS | Professional & scientific | 2005 |
| Oshaug Metall AS | Manufacturing | 2000 |
| Oskar Sylte Holding AS | Real estate | 1972 |
| Oskar Sylte Invest AS | Real estate | 2013 |
| Oskar Sylte Mineralvannsfabrikk AS | Manufacturing | 1991 |
| Oslo Bolig Invest AS | Real estate | 2006 |
| Oterhals Holding AS | | 2024 |
| Otto H AS | Manufacturing | 2013 |
| Outzen Hjørnet AS | Real estate | 2019 |
| Outzen Strøket AS | Real estate | 2007 |
| P. K. Johnsen Holding AS | Health & social care | 2005 |
| P.Holding AS | Other services | 2017 |
| Pamatred Stomoco AS | | 2026 |
| Pamoloth AS | Health & social care | 2005 |
| Panorama B2 AS | Real estate | 2007 |
| Panorama Bowling AS | Arts & recreation | 2015 |
| Panorama Bygg AS | Construction | 2022 |
| Panorama Invest AS | Real estate | 1997 |
| Panorama Plan AS | Real estate | 2020 |
| Panorama Vekst AS | Real estate | 2020 |
| Papas AS | | 2021 |
| Paraply AS | | 2021 |
| Park Nøisomhedsveien AS | Real estate | 2007 |
| Parkering Invest AS | Real estate | 2015 |
| Parkgården AS | Real estate | 2002 |
| Parkvegen 72 AS | Real estate | 2007 |
| Pasco Eiendom AS | Professional & scientific | 2014 |
| PB Technology AS | | 2021 |
| PBH Elektro AS | Construction | 2022 |
| Peam Invest AS | | 2021 |
| Pella Invest AS | | 2021 |
| Peninsula Holding AS | Real estate | 2016 |
| Pepper Blue Medical AS | Health & social care | 2015 |
| Pepper Holding AS | Health & social care | 2015 |
| Per Tverfjell Bilomsetning AS | Other services | 1990 |
| Perfect Fit Systue AS | Other services | 2025 |
| Perisec AS | Professional & scientific | 2020 |
| Perok Invest AS | Real estate | 2015 |
| Peru Holding AS | | 2011 |
| Petras AS | Professional & scientific | 2025 |
| Peza AS | Hospitality | 2015 |