| Integrasjonspartner Bits AS | Information & communication | 1997 |
| Intellipush AS | Information & communication | 2013 |
| Interiørmuring AS | Construction | 1999 |
| International Management Consultant AS | Professional & scientific | 2018 |
| Internsystem Consulting AS | Information & communication | 2012 |
| Invest Group AS | Transport & logistics | 2023 |
| Invest in Green AS | Real estate | 2021 |
| Investeringsselskapet Skogstrand AS | | 2020 |
| Investing AS | Construction | 2022 |
| Iot Proffen AS | Information & communication | 2020 |
| Iroc AS | Wholesale & retail | 2008 |
| Irr Invest AS | | 2024 |
| Isegran Eiendom AS | Real estate | 2018 |
| Ispas AS | Information & communication | 2001 |
| IT Direct Da | Information & communication | 2001 |
| IT Gustavsen AS | | 2023 |
| Italiamo AS | Administrative & support | 2017 |
| Italienske Delikatesser AS | Wholesale & retail | 2020 |
| Itz Mat AS | Hospitality | 2025 |
| Ivar Lier AS | Wholesale & retail | 1971 |
| Ivi Holding AS | Other services | 2005 |
| J. Pettersen Invest AS | Financial services | 2012 |
| J.M.L Holding AS | | 2023 |
| Jaca Eiendom AS | Real estate | 1999 |
| Jachs Da | Manufacturing | 2010 |
| Jacobsen, Leander & Co AS | Health & social care | 2012 |
| Jamit AS | Information & communication | 2022 |
| Jan B Holding AS | | 2023 |
| Jan Erling Grav Invest AS | Financial services | 2007 |
| Jan G Larsen AS | Wholesale & retail | 1987 |
| Jan-Erik Zakariassen Holding AS | Professional & scientific | 2005 |
| Jansen Byggservice AS | Construction | 2018 |
| Jan`S Catering Da | Hospitality | 1996 |
| Jchsm AS | | 2024 |
| Jda AS | Agriculture & fishing | 2024 |
| Je Defence AS | Professional & scientific | 2021 |
| Jeans Corner AS | Wholesale & retail | 1992 |
| Jegr Frisør AS | Other services | 2024 |
| Jei Invest Øst AS | Real estate | 2019 |
| Jenkol AS | | 2026 |
| Jensen Bygg & Eiendom AS | Real estate | 1999 |
| Jensen Eiendom AS | Real estate | 1995 |
| JES1 Bygg AS | Construction | 2019 |
| Jesper Skøien Holding AS | | 2026 |
| Jetlife AS | Arts & recreation | 2015 |
| Jgroup AS | Information & communication | 2013 |
| Jiwa Holding AS | Hospitality | 2023 |
| JJM Holding AS | Hospitality | 2022 |
| Jlsp Investment AS | Professional & scientific | 2024 |
| JN Kompetanse AS | Health & social care | 2022 |
| Job AS | | 2021 |
| Jofaz AS | Manufacturing | 1994 |
| Johan Mathisen Ur - Optikk AS | Wholesale & retail | 2022 |
| Johannes Johannessen AS | Real estate | 2006 |
| John Martinsen Trafikkskole AS | Education | 1981 |
| Johnnys Pizza AS | Hospitality | 2018 |
| Johntor Maskiner AS | Construction | 2010 |
| Joker Tekst & Tegning Da | Wholesale & retail | 2008 |
| Joki Engineering AS | Professional & scientific | 2019 |
| Joma Holding AS | Administrative & support | 2005 |
| Joma Invest AS | Financial services | 2005 |
| Joma Trading Norway AS | Wholesale & retail | 2010 |
| Jopa Holding AS | | 2023 |
| Josef Bygg AS | Construction | 2022 |
| Jotek AS | Real estate | 2004 |
| Jpa Holding AS | Financial services | 2005 |
| JPP Holding AS | Real estate | 2005 |
| JR Gassline Holding AS | | 2022 |
| JRT Holding AS | Professional & scientific | 2011 |
| JS Sjøberg Holding AS | Financial services | 2014 |
| Julie Andrea Holding AS | | 2025 |
| Juvel Gullsmedforretning Fredrikstad AS | Wholesale & retail | 1982 |
| Jva Entreprenør AS | Construction | 2023 |
| Jwillya Consulting AS | Professional & scientific | 2022 |
| Jørgen Eriksen AS | Wholesale & retail | 2017 |
| Jørn Gabrielsen Holding AS | Financial services | 2005 |
| Jørn Willy Andersen AS | Wholesale & retail | 2022 |
| K-H Eiendom AS | Real estate | 1996 |
| K. Ljosnes AS | Professional & scientific | 2024 |
| Kaa Bygg-Takst AS | Real estate | 2024 |
| Kacaloma AS | Real estate | 2005 |
| Kaffe Koppen Distribusjon AS | Wholesale & retail | 2013 |
| Kago AS | Other services | 2022 |
| Kahn Elektro AS | Construction | 2011 |
| Kaholmen AS | Real estate | 2020 |
| Kaja Marie AS | Professional & scientific | 2021 |
| Kalnes Terrasse AS | Real estate | 2016 |
| Kam Holding AS | | 2013 |
| Kampo Eiendom AS | Real estate | 2011 |
| Kampus AS | Information & communication | 2017 |
| Kappahl AS | Wholesale & retail | 1988 |
| Karg AS | Health & social care | 2021 |
| Karivold Invest AS | Information & communication | 2005 |
| Karlshusjordet Boligutleie AS | Real estate | 2017 |
| Karriereverktøy AS | Professional & scientific | 2015 |
| Karsten Fossum AS | Transport & logistics | 2005 |
| Karsten Fossum Transport AS | Construction | 2019 |
| Kasoria Invest AS | | 2021 |
| Kavi Invest AS | Financial services | 2007 |
| KB Bygg Og Takst AS | Real estate | 2026 |