| Montenor AS | Real estate | 2006 |
| Mor Solhaug AS | Professional & scientific | 2005 |
| Morten Arnesen Consulting AS | Real estate | 2016 |
| Morten AS | Administrative & support | 2005 |
| Moserud AS | | 2022 |
| Motbakken AS | Information & communication | 2022 |
| Moto Marine Way AS | Wholesale & retail | 2024 |
| MPT Service Nuf | Manufacturing | 2014 |
| Multi Kraft AS | Construction | 1995 |
| Myrhaug Gartneri Da | Agriculture & fishing | 2012 |
| Myrvang Invest AS | Information & communication | 2005 |
| NB Elektro AS | Construction | 2017 |
| Nedre Lian Invest AS | Professional & scientific | 2018 |
| Nedre Tverrgate 3 Næring AS | Real estate | 2022 |
| Neokon AS | Health & social care | 1995 |
| Nero Invest AS | Financial services | 2005 |
| Nett & El Teknikk AS | Construction | 2017 |
| Nettcompaniet AS | Financial services | 2005 |
| Nicwil AS | Hospitality | 2005 |
| Nim Consulting AS | Professional & scientific | 2024 |
| Nimeco AS | Water & waste | 1990 |
| Nimlas Norway AS | Construction | 2014 |
| Nimlas Norway Bidco AS | Construction | 2022 |
| Nimlas Norway Holding AS | Construction | 2019 |
| Nimlas Norway Midco AS | Construction | 2022 |
| Niva Eiendom AS | Health & social care | 2006 |
| Nm-Byggservice AS | Construction | 2008 |
| NMB Holding AS | | 2013 |
| NO.1 Consulting AS | Professional & scientific | 2026 |
| Noahs Ark Miljøbarnehage AS | Education | 2007 |
| Nodan Bygg Norsk Avdeling Av Utenlandsk Foretak Nuf | | 2001 |
| Nomedia AS | Information & communication | 2013 |
| Nomedia Norge Limited Nuf | Information & communication | 2007 |
| Nordic Bad AS | Construction | 2018 |
| Nordic Defence Industries AS | Wholesale & retail | 2008 |
| Nordic Vindusrengjøring AS | Administrative & support | 2025 |
| Norfilm AS | Information & communication | 1993 |
| Norfjær AS | Manufacturing | 2012 |
| Norient Consult AS | Professional & scientific | 2012 |
| Norsk Bingodrift AS | Arts & recreation | 2008 |
| Norsk Garanti & Reklamasjon AS | Professional & scientific | 2020 |
| Norvann AS | Construction | 2002 |
| Norvann Holding AS | Construction | 2007 |
| Norwegian Insurance Management AS | Financial services | 2016 |
| Noses of Norway AS | Other services | 2015 |
| Nykjua Invest AS | | 2015 |
| Nytavtre AS | Wholesale & retail | 2023 |
| Nøste Barnehage SA | Education | 1996 |
| Nøste Legekontor AS | Health & social care | 2006 |
| Nøsteveien 75 AS | Real estate | 2025 |
| Oak Equity AS | Real estate | 2020 |
| Oats & Berries Da | Professional & scientific | 2025 |
| Odins AS | Manufacturing | 2020 |
| Olav Wierli Holding AS | Financial services | 2005 |
| Ole Bror Bentsen AS | Construction | 2003 |
| Oppegård Dagligvare AS | Wholesale & retail | 2025 |
| Optimal Helse & Omsorg AS | Health & social care | 2015 |
| Oraculus AS | Professional & scientific | 2013 |
| Originatorz IT & Software Professionals AS | Professional & scientific | 2023 |
| Orlmed AS | Health & social care | 2020 |
| Orre Maskin Service AS | Manufacturing | 2004 |
| Oslo Fjord by Sail AS | Administrative & support | 2025 |
| Oslo Og Follo Busstrafikk AS | Transport & logistics | 1999 |
| Oslo Truck Wash AS | Other services | 2021 |
| Ot Auto AS | | 2020 |
| Oves Rammeverksted Og Helsekost AS | Wholesale & retail | 1992 |
| Paal Hage Holding AS | Manufacturing | 2005 |
| Parkinson - for a Better Life AS | Professional & scientific | 2017 |
| Parkveien 8 Invest AS | | 2019 |
| Pasys AS | Professional & scientific | 2017 |
| Pathoma Consult & Invest AS | Administrative & support | 2008 |
| PBN Eiendomsutvikling AS | Real estate | 2009 |
| PBN Invest AS | Real estate | 2005 |
| Pe-Ny AS | | 2024 |
| Pena Invest AS | | 2024 |
| Peritum Auto AS | Other services | 2023 |
| Perkarls AS | | 2021 |
| Pes Transport Og Graving AS | Administrative & support | 2006 |
| Peter Rudolfsen Holding AS | Information & communication | 2021 |
| Phans AS | | 2021 |
| Pharo Holding AS | Health & social care | 2022 |
| Pharo Tannhelse AS | Health & social care | 2022 |
| Pibli Holding AS | Professional & scientific | 2018 |
| Pimba AS | Professional & scientific | 2018 |
| Pioner Eiendom AS | Real estate | 2002 |
| Pko AS | Administrative & support | 2015 |
| Plutus AS | Agriculture & fishing | 2017 |
| Pop Holding AS | Financial services | 2018 |
| Powerx AS | Professional & scientific | 2024 |
| Prim AS | Wholesale & retail | 2026 |
| Proactive Systems AS | Professional & scientific | 2016 |
| Proffkjøkken AS | Wholesale & retail | 2023 |
| Profpower AS | Administrative & support | 1987 |
| Projecthelp AS | Information & communication | 2000 |
| Promanit AS | Real estate | 2001 |
| Protan AS | Manufacturing | 2001 |
| Protan Entreprenør AS | Construction | 2001 |
| Protencon AS | Information & communication | 2019 |
| Protman Invest AS | | 2019 |
| Proturf AS | Wholesale & retail | 2016 |