| Multibygg AS Ingeniør- Og Entreprenørforretning | Construction | 1989 |
| Multibygg Eiendom AS | Real estate | 2025 |
| Multibygg Holding AS | Real estate | 2024 |
| Multibygg Håndverk AS | Construction | 2023 |
| Murmester Per Andersen AS | Construction | 1989 |
| Mychoice AS | Wholesale & retail | 2006 |
| N a Biørn Lian Ltd AS | Wholesale & retail | 1990 |
| N&T Holding AS | Real estate | 2015 |
| Na Regnskap AS | Professional & scientific | 2026 |
| Nablo Eiendom AS | Real estate | 1966 |
| Natursteinleggeren AS | Construction | 2007 |
| NDS Group AS | Wholesale & retail | 1963 |
| Nedre Lie Garasjelag SA | Real estate | 1987 |
| Nettfokus AS | Information & communication | 2024 |
| NGS Asset Management AS | | 2025 |
| NGS Eiendom Invest AS | Real estate | 2025 |
| Nile Invest AS | Wholesale & retail | 2007 |
| Nittedal Holding AS | Transport & logistics | 2019 |
| Nittedal Renhold Og Flyttebyrå AS | Administrative & support | 2013 |
| Nittedal Service AS | Manufacturing | 2025 |
| Nittedal Sjokoladefabrikk AS | Manufacturing | 2020 |
| NMS Holding AS | | 2021 |
| No Limit Holding AS | Financial services | 2008 |
| Noah's Ark AS | | 2025 |
| Noahs Transport AS | Transport & logistics | 2025 |
| Nodevo AS | Information & communication | 2026 |
| Nokab Eiendom AS | Real estate | 2019 |
| Nor Camp AS | Wholesale & retail | 1979 |
| Nor-Konsulenten AS | Professional & scientific | 1979 |
| Nor-Racing Da | Wholesale & retail | 1997 |
| Norarm AS | Manufacturing | 2019 |
| Nord Eiendom II AS | | 2006 |
| Nord-Kran AS | Wholesale & retail | 1981 |
| Nordic Brand Hub AS | Wholesale & retail | 2016 |
| Nordic Tools AS | Wholesale & retail | 2012 |
| Nordisk Renhold AS | Administrative & support | 2020 |
| Norena AS | Manufacturing | 2006 |
| Norena Presenning AS | Manufacturing | 2005 |
| Norgesmarkiser Amico AS | Wholesale & retail | 1990 |
| Norhak Holding AS | | 2026 |
| Norma AS | Wholesale & retail | 1986 |
| Norpol Tolk Og Helse AS | Professional & scientific | 2018 |
| Norsk Avlastningssenter Da | Health & social care | 1997 |
| Norsk Iskrem AS | Construction | 1989 |
| Norsk Opplæring AS | Education | 2011 |
| Northbrew AS | Manufacturing | 2022 |
| Norwegian Mobility Group AS | Wholesale & retail | 2000 |
| Norwegian Pure Energy AS | Professional & scientific | 2019 |
| Norwegian Sales Group AS | Wholesale & retail | 2016 |
| Nye Eltonåsen Nærsenter AS | Real estate | 2019 |
| Nye Harris Auto AS | Wholesale & retail | 2025 |
| Nye Heggtoppen 1 Eiendom AS | Real estate | 2019 |
| Nye Johansken AS | Wholesale & retail | 2021 |
| Nye Stallbakken 3 Eiendom AS | Real estate | 2019 |
| Nymo Health AS | Health & social care | 2019 |
| Nyskareig AS | Real estate | 2005 |
| Nytomta AS | Real estate | 2022 |
| Nyvoll Consult AS | Professional & scientific | 2008 |
| October Consulting AS | Professional & scientific | 2010 |
| Odinteq AS | Professional & scientific | 2017 |
| Oldenburger Norge AS | Transport & logistics | 2019 |
| Olsen Maskindrift AS | Construction | 2025 |
| Omega Norge AS | Professional & scientific | 2009 |
| On-Ramp AS | Administrative & support | 2019 |
| Onhold AS | Real estate | 2018 |
| Onkel Skrue Kapital AS | Real estate | 2006 |
| Onlog AS | Information & communication | 2021 |
| Oplandske Spritfabrik Ans | Manufacturing | 2000 |
| Optimal Bygg & Eiendom AS | Real estate | 2002 |
| Optipos AS | Financial services | 2013 |
| Oslo Finerfabrikk Holding AS | Wholesale & retail | 2017 |
| Oslo Mikrosement AS | Construction | 2024 |
| Oslo Retail AS | Wholesale & retail | 2018 |
| Oslo Termografi Og Byggteknikk AS | Professional & scientific | 2013 |
| Oslo Trykkluft AS | Wholesale & retail | 2010 |
| Oslo Trykkluft Holding AS | Wholesale & retail | 1991 |
| Oslofinér AS | Wholesale & retail | 2017 |
| Oso Holding AS | | 2014 |
| Overn Holding AS | Information & communication | 2020 |
| Ovit Consulting AS | Information & communication | 2020 |
| Oxygen Furniture AS | Wholesale & retail | 2022 |
| OY Wilfa Suomi AB | Wholesale & retail | 2015 |
| P.R. Holding AS | Real estate | 1970 |
| Pallelogistikk AS | Transport & logistics | 2019 |
| Parken Barnehage Ans | Education | 2002 |
| Pasike Invest AS | Real estate | 2006 |
| Pckinvest AS | Wholesale & retail | 1994 |
| Pcteam Support AS | Information & communication | 2012 |
| Persgaard Møbler AS | Wholesale & retail | 2018 |
| Petam AS | | 2024 |
| Petter Fallet Invest AS | Financial services | 2016 |
| PGN Holding AS | | 2023 |
| Philettersson Invest AS | | 2020 |
| Piccola Napoli AS | Hospitality | 2025 |
| Pixnord AS | Construction | 1987 |
| Pizzadrift Hagan AS | Hospitality | 2020 |
| PK Skrenten Invest AS | | 2005 |
| Plan- Og Prosjektpartner AS | Professional & scientific | 2006 |
| Platekonstruksjoner AS | Financial services | 1993 |
| Playball Da | Wholesale & retail | 2003 |