| Middelhavet Mat AS | Hospitality | 2023 |
| Mikon Transport AS | Transport & logistics | 2024 |
| Minaas AS | Professional & scientific | 2022 |
| Miriams Hemmelige Hage AS | Wholesale & retail | 2020 |
| MKJ Gruppen AS | | 2026 |
| MKS Anleggstjenester AS | Construction | 2024 |
| MKS Askim AS | Real estate | 2017 |
| Mobren AS | | 2022 |
| Monicas Magiske Hjørne AS | Education | 2020 |
| Montasjekompaniet AS | Construction | 2005 |
| Moonhaven's Mindspace AS | Arts & recreation | 2017 |
| Mori Showroom AS | Manufacturing | 2025 |
| Motar AS | Real estate | 2020 |
| Mustang Bygg Og Jordbruk AS | Construction | 2021 |
| Mxym Cap AS | | 2025 |
| My Cab 24 AS | Transport & logistics | 2025 |
| Myrveien Næringspark AS | Real estate | 2018 |
| Mysen - Jernbanegata 2 AS | Real estate | 2025 |
| Møbel-Land AS | Wholesale & retail | 2014 |
| Nabolagshelse AS | Information & communication | 2024 |
| Nacamed AS | Professional & scientific | 2017 |
| Navigatio AS | Professional & scientific | 2013 |
| Nazari Invest AS | | 2024 |
| Netlandet Holding AS | | 2025 |
| Nexima AS | Information & communication | 1998 |
| Next Level Group AS | Real estate | 2016 |
| Nier'N AS | Real estate | 2024 |
| Niklas Hansen Holding AS | Information & communication | 2020 |
| Nilsen Bilservice AS | Other services | 1995 |
| Nilsens Vaktmester Service AS | Administrative & support | 2018 |
| Nilsens Vaktmesterservice AS | Real estate | 2024 |
| Niord Lydfabrikk AS | Information & communication | 2024 |
| Noble Holding AS | Professional & scientific | 2006 |
| Nodin Aviation AS | Professional & scientific | 1998 |
| Nor-Transport AS | Transport & logistics | 1979 |
| Norcampers AS | Wholesale & retail | 2022 |
| Nordbye & Co Divisjon Hengere AS | Agriculture & fishing | 1986 |
| Nordhavn AS | Real estate | 2023 |
| Nordhavn Property AS | Real estate | 2024 |
| Nordic Sound & Light AS | Arts & recreation | 2024 |
| Nordic Waterproofing AS | Wholesale & retail | 2000 |
| Nordlys Helse AS | Health & social care | 2025 |
| Nordmarkens Fasader AS | Wholesale & retail | 2019 |
| Nordmarkens Ventilasjon AS | Construction | 2018 |
| Norhair AS | Wholesale & retail | 1998 |
| Noring AS | Professional & scientific | 1987 |
| Norkredit AS | Administrative & support | 2003 |
| Norlett Service AS | Wholesale & retail | 1990 |
| Normann Etek AS | Construction | 2018 |
| Norsk Automasjon AS | Professional & scientific | 1987 |
| Norsk Frekvenssikkerhet AS | Administrative & support | 2025 |
| Norsk Kuldeservice AS | Construction | 2011 |
| Norsk Matraps SA | Agriculture & fishing | 2001 |
| Norsk Nyskapnings Institutt AS | Real estate | 1992 |
| Norsk Prodarts AS | Administrative & support | 2021 |
| Norsk Sakkyndig Og Tilsynsvirksomhet AS | Professional & scientific | 2019 |
| Norsk Ullgris Da | Agriculture & fishing | 2018 |
| Nour Holding AS | Health & social care | 2024 |
| Nour Lab Consult AS | Professional & scientific | 2023 |
| Novo Klinikken AS | Health & social care | 2020 |
| Novofilm AS | Information & communication | 2026 |
| NS Invest AS | Real estate | 2020 |
| Nsu Invest AS | | 2021 |
| Nuda.M. AS | Hospitality | 2020 |
| Nye Glommen Revisjon AS | Professional & scientific | 2010 |
| Nye Normex Da | Wholesale & retail | 1989 |
| Nærbytunet AS | Real estate | 2021 |
| Obnatus AS | Professional & scientific | 2010 |
| Odd Kåre Gamlem AS | Wholesale & retail | 2006 |
| Odontia 3 AS | Health & social care | 2018 |
| Og Solutions AS | | 2025 |
| Ojh-Holding AS | Real estate | 2020 |
| Okshovd Invest AS | Construction | 2021 |
| Ola Frøshaug Holding AS | Other services | 2005 |
| Ola Nordmann AS | Information & communication | 2021 |
| Ole Ha Holding AS | Wholesale & retail | 2023 |
| Olsen Drone Og Rov Tjenester AS | Professional & scientific | 2026 |
| Olsen&Co AS | | 2023 |
| Omar AS | Transport & logistics | 2023 |
| Omtvedt AS | Health & social care | 2021 |
| Onegolf AS | Wholesale & retail | 2021 |
| Onetraffic Norway AS | Information & communication | 2013 |
| Opplevelsessenteret Østfoldbadet AS | Arts & recreation | 1998 |
| Opsduty AS | Information & communication | 2023 |
| Optocom AS | Construction | 2021 |
| Opus Management AS | Professional & scientific | 1990 |
| Oraug Kylling-Oppdrett AS | Agriculture & fishing | 2020 |
| Ord Og Bilder Rigmor Og Øivind Berge | Professional & scientific | 1986 |
| Origoo AS | Information & communication | 2026 |
| Orkide Restaurant AS | Hospitality | 2012 |
| Os Handel AS | Wholesale & retail | 2026 |
| Oslo Rørservice AS | Construction | 2018 |
| Osloveien 214 AS | Real estate | 2011 |
| Osloveien 33 Eiendom AS | Real estate | 2014 |
| Osloveien 91 AS | Real estate | 2020 |
| Osloveien Bil AS | Wholesale & retail | 1974 |
| Outlet Bilvask AS | Other services | 2025 |
| Outlet Super Bilvask AS | Other services | 2014 |
| P.V. Jensen Eiendom AS | Real estate | 1979 |
| Paravel AS | Information & communication | 2022 |