| Nanopow AS | Professional & scientific | 2016 |
| Narvesen Revisjon AS | Professional & scientific | 2013 |
| NB Maskin AS | Transport & logistics | 2024 |
| NCG Eiendom AS | Real estate | 2014 |
| NCG Eiendom Holding AS | Real estate | 2023 |
| NCG Sementimport AS | Wholesale & retail | 2020 |
| NCG Transport AS | Transport & logistics | 2022 |
| NDS Eiendom AS | Real estate | 2020 |
| NDS Holding AS | Real estate | 2018 |
| Nederberg Nilsen Jord Og Skog Ans | Agriculture & fishing | 2023 |
| Nedre Langeland Utvikling AS | Real estate | 2022 |
| Nemus Kongsvinger AS | Health & social care | 2013 |
| Neptune Manufacturing AS | Manufacturing | 2025 |
| Nor Spor AS | Construction | 2024 |
| Nor Spor Holding AS | Construction | 2024 |
| Nordbohus Kongsvinger AS | Construction | 1994 |
| Nordbohus Kongsvinger Eiendom AS | Real estate | 2005 |
| Nordic Commodities AS | Professional & scientific | 2012 |
| Nordic Concrete Group AS | Manufacturing | 2017 |
| Nordic Loader AS | Wholesale & retail | 2025 |
| Nordic Tank AS | Other services | 2002 |
| Nordic Travel Services AS | Information & communication | 2020 |
| Nordisk Handel IV AS | Real estate | 2011 |
| Nordmark Industri Service AB Nuf | Manufacturing | 1998 |
| Nordwiik AS | Real estate | 2013 |
| Norexeco ASA | Financial services | 2012 |
| Norges Toppidrettsgymnas Kongsvinger AS | Education | 2006 |
| Norges Toppidrettsgymnas Ungdomsskole Kongsvinger AS | Education | 2015 |
| Norma Nordiske Markedsundersøkelser AS | Professional & scientific | 2003 |
| Norsenga Eiendom AS | Wholesale & retail | 2007 |
| Norsenteret Kongsvinger SA | Wholesale & retail | 1960 |
| Norsk Motorsport Service AS | Wholesale & retail | 2012 |
| Norske Backer AS | Manufacturing | 1969 |
| Norstrøm Consulting AS | Professional & scientific | 1987 |
| Norvald Strands Veg 43 AS | Real estate | 2017 |
| Norvald Strands Veg 45-47 AS | Real estate | 2022 |
| Norway Sustainability AS | Professional & scientific | 2021 |
| Norwegian Hunting Da | Administrative & support | 2006 |
| Norwice AS | Professional & scientific | 2018 |
| NR Eiendom AS | Real estate | 2010 |
| NRG Transport AS | Transport & logistics | 2016 |
| Nuevo AS | Wholesale & retail | 2017 |
| Ny Vekst AS | Health & social care | 2019 |
| Ny Wa Invest AS | Real estate | 1990 |
| Nyborg Entreprenør AS | Real estate | 2023 |
| Nye Bilco Kongsvinger AS | Other services | 2012 |
| Nye Glåmdal Dyreklinikk AS | Professional & scientific | 2026 |
| Nye Sporten AS | Wholesale & retail | 1975 |
| Nygård Autoservice AS | Wholesale & retail | 2022 |
| Nylænder AS | Wholesale & retail | 1932 |
| Nystø Bygg AS | Real estate | 2024 |
| Nystø Holding AS | | 2026 |
| Oasen Hårstudio AS | Other services | 2013 |
| Oc Invest AS | Arts & recreation | 2016 |
| Ocka Eiendom AS | Real estate | 2012 |
| Odal Bil Kongsvinger AS | Other services | 2012 |
| Odal Trafikkskole AS | Education | 2014 |
| Odal Økonomi AS | Professional & scientific | 1999 |
| Offline Trening AS | Arts & recreation | 2019 |
| Oftalmo AS | Health & social care | 2017 |
| Ok Service AS | Wholesale & retail | 2024 |
| Olaskogen AS | Real estate | 2005 |
| Ombj Invest AS | | 2022 |
| Omsaso Holding AS | | 2022 |
| One Reklame Da | Professional & scientific | 1987 |
| Op Maskin AS | Manufacturing | 2018 |
| Op Maskin Eiendom AS | Real estate | 2004 |
| Op Maskin Holding AS | Manufacturing | 2018 |
| Optice AS | Administrative & support | 2012 |
| Optice Eco Tec AS | Construction | 2026 |
| Optiversion AS | Professional & scientific | 2018 |
| Or Eiendom AS | Real estate | 1998 |
| Or Invest AS | Financial services | 1995 |
| Orblytic AS | Information & communication | 2024 |
| Originaldekor AS | Professional & scientific | 2021 |
| Oslo Handel Og Vandel AS | Professional & scientific | 2022 |
| Otel Eiendom AS | Real estate | 2023 |
| Otervegen 14 AS | Real estate | 2018 |
| Oustad Holth Eiendom AS | Real estate | 2022 |
| Oustad Holth Prosjektering AS | Real estate | 2015 |
| Ovlien & Co. AS | Professional & scientific | 2019 |
| Parken Kjøpesenter AS | Real estate | 2003 |
| Parkett & Interiør AS | Construction | 2013 |
| Parkvegen 12 AS | Real estate | 2007 |
| Parkvegen 27 AS | Real estate | 2007 |
| Pax Mat AS | Wholesale & retail | 2019 |
| Pay Back A/S | Professional & scientific | 1988 |
| Peders Kjøtt Og Fisk AS | Wholesale & retail | 2023 |
| Pentacon AS | Professional & scientific | 2002 |
| Per Og Pia Ans | | 1988 |
| Pers Glass Service AS | Construction | 1995 |
| Perspic AS | Information & communication | 2022 |
| Pinor AS | | 1997 |
| Pizzaria Palermo AS | Hospitality | 2022 |
| PK2 Investering AS | | 2026 |
| Platek Invest AS | Real estate | 2016 |
| Plenmester 1 AS | Administrative & support | 2008 |
| Ponsse AS | Wholesale & retail | 1998 |
| Port Norge AS | Professional & scientific | 2025 |
| Posteringen Eiendom AS | Real estate | 2017 |