| Invera Water AS | Information & communication | 2025 |
| Invest 5 AS | Real estate | 2011 |
| Invest KB AS | | 2026 |
| Invest Midt-Norge AS | Real estate | 2004 |
| Investida AS | Administrative & support | 2025 |
| Investika AS | Financial services | 2009 |
| Investinor AS | Financial services | 2008 |
| Investinor Direkte AS | Financial services | 2020 |
| Investinor Indirekte I AS | Financial services | 2020 |
| Investinor Indirekte II AS | Financial services | 2020 |
| Investinor Nord-Norge AS | Financial services | 2018 |
| Investinor Skog AS | Financial services | 2023 |
| Investitude AS | Financial services | 2005 |
| Investivalue AS | | 2025 |
| Investo AS | Real estate | 2005 |
| Inviest Holding AS | | 2025 |
| Invite Design Da | Information & communication | 2003 |
| Invoice Club AS | Information & communication | 2013 |
| Inzynk AS | Professional & scientific | 2016 |
| IP Eiendom AS | Real estate | 2016 |
| IP Tjenesten Da | Information & communication | 2006 |
| Ipj Produksjon AS | Manufacturing | 2008 |
| Ippo Invest AS | Real estate | 2021 |
| Iq Invest AS | Real estate | 2000 |
| Iqon Global AS | Information & communication | 2023 |
| Iqon Holding AS | Information & communication | 2011 |
| Ir Oust Eiendom AS | Real estate | 2014 |
| Irigea Holding AS | Professional & scientific | 2020 |
| Irøef AS | | 2021 |
| Isak Borkmo Holding AS | | 2025 |
| Isaksen Kommunikasjon AS | Professional & scientific | 2016 |
| Isavi AS | Real estate | 2025 |
| Isb Holding AS | Real estate | 2016 |
| Isern Consulting AS | | 2005 |
| Ish AS | Financial services | 2017 |
| Isma AS | | 2017 |
| Iso Invest AS | | 2021 |
| Isocare AS | Professional & scientific | 2001 |
| Istanbul Express AS | Hospitality | 2013 |
| Isyd Eiendom AS | Real estate | 1996 |
| IT Consept AS | Wholesale & retail | 2001 |
| It's Me Id AS | Manufacturing | 2018 |
| Itelsec Nuf | Information & communication | 2020 |
| Itema AS | Information & communication | 2000 |
| Ith Holding AS | Professional & scientific | 2021 |
| Its Working AS | Information & communication | 2026 |
| Itsense AS | Information & communication | 2016 |
| Itsjefen AS | Information & communication | 2021 |
| Itsjefen Holding AS | | 2021 |
| Ivar Arnesen Invest AS | Real estate | 2005 |
| Ivar C. Ulvan Holding AS | Transport & logistics | 2005 |
| Ivar Lykkes Vei 2 Hjemmel AS | Real estate | 2005 |
| Ivar Lykkes Vei 4 AS | Real estate | 2012 |
| Ivar Lykkes Vei 9 AS | Real estate | 2008 |
| Ivar Nicolai Askelund Holding AS | | 2019 |
| Ivc AS | | 2020 |
| Ive Media AS | Information & communication | 2017 |
| Iveli Holding AS | | 2026 |
| Ivema Holding AS | Administrative & support | 2006 |
| Iventor Da | Education | 2001 |
| Iver Accelerate Trondheim AS | Professional & scientific | 2020 |
| Iver Westerlund AS | Administrative & support | 2023 |
| Iverksetter AS | Information & communication | 2024 |
| Iversen Bygg AS | Construction | 2025 |
| Iversen Mek & Rep AS | Manufacturing | 2019 |
| Iversen Rådgivning AS | Information & communication | 2016 |
| Ivi Utleie AS | Wholesale & retail | 2026 |
| Ivia AS | Manufacturing | 2026 |
| Ivs Holding AS | | 2021 |
| Iwi Consulting AS | Information & communication | 2005 |
| Izulu AS | Professional & scientific | 2024 |
| Ingeniørfirmaet Gummi & Maskinteknikk AS | Wholesale & retail | 1982 |
| J & J Accessory Da | Wholesale & retail | 2009 |
| J & JP Property AS | Real estate | 2012 |
| J Berg Holding AS | Real estate | 2005 |
| J Bjørnaas Invest AS | | 2021 |
| J J Holding AS | Professional & scientific | 2005 |
| J L Holding AS | | 2026 |
| J P Strøm Shipping - Hitra AS | Transport & logistics | 2024 |
| J P Strøm Shipping AS | Transport & logistics | 1989 |
| J Skarpeteig AS | | 2017 |
| J&A Investments AS | | 2025 |
| J-Sg AS | Real estate | 2016 |
| J. Aa Holding AS | | 2020 |
| J. Normann Holding AS | | 2026 |
| J.A.G. Holding AS | Real estate | 2005 |
| J.A.N Holding AS | | 2016 |
| J.Andresen Holding AS | Wholesale & retail | 2024 |
| J.B.J. Holding AS | Real estate | 2008 |
| J.B.T Holding AS | | 2024 |
| J.L. Holding AS | | 2025 |
| Jaag Holding AS | Real estate | 2023 |
| Jacobs Restauranter AS | Hospitality | 1991 |
| Jacta AS | Real estate | 2005 |
| Jae Invest AS | Financial services | 2017 |
| Jag Asset AS | Information & communication | 2016 |
| Jagenberg AS | Professional & scientific | 2019 |
| Jahle Capital AS | | 2023 |
| Jahn-Ove Askvik Holding AS | | 2023 |
| Jakata Invest AS | Financial services | 2005 |