| Jhmm AS | Real estate | 2022 |
| Jhoff Invest AS | | 2023 |
| Jhs-Holding AS | | 2021 |
| Jila AS | Financial services | 2017 |
| Jinovest AS | | 2026 |
| Jis Invest AS | Professional & scientific | 2014 |
| Jit Eiendom AS | Real estate | 2025 |
| JJ Nailcare AS | Other services | 2019 |
| Jja Bygg AS | Construction | 2019 |
| JK Eiendom Og Invest AS | Real estate | 2011 |
| JK Offshore AS | Professional & scientific | 2013 |
| JK Service Kret AS | Transport & logistics | 2018 |
| Jka Holding AS | | 2025 |
| Jkek Holding AS | | 2022 |
| Jkel Invest AS | | 2024 |
| JKS Invest AS | | 2020 |
| JKS Tjenester AS | Administrative & support | 2026 |
| JKT Invest AS | Financial services | 2005 |
| JM Nervik AS | Professional & scientific | 2024 |
| Jmi Invest AS | Financial services | 2005 |
| JMJ Invest AS | | 2019 |
| Jmk-Sentret | Wholesale & retail | 1995 |
| JMP Consulting AS | Education | 2014 |
| JMR Capital AS | | 2023 |
| Jmu Holding AS | Other services | 2023 |
| JMW Invest AS | Real estate | 2006 |
| Jo Askelund Holding AS | Real estate | 2019 |
| Jo Holding AS | Administrative & support | 2021 |
| Jo Ko AS | Wholesale & retail | 2024 |
| Jo Utleie AS | Administrative & support | 2022 |
| Jo-Ma AS | Financial services | 2005 |
| Joadjo AS | Professional & scientific | 2006 |
| Joakim Lund Holding AS | Real estate | 2018 |
| Jobben Min AS | Arts & recreation | 2016 |
| Jobbtreff AS | Information & communication | 2026 |
| Jobzone Trøndelag AS | Administrative & support | 2004 |
| Joelsi Holding AS | Real estate | 2019 |
| Jogr AS | | 2021 |
| Joh Vannteknikk AS | Professional & scientific | 2016 |
| Johan Andresen AS | Construction | 1946 |
| Johan Andresen Eiendom AS | Construction | 2016 |
| Johan Brobakke AS | Professional & scientific | 1991 |
| Johan Høye Holding AS | | 2025 |
| Johan O Helgesen AS | Real estate | 1960 |
| Johan Sandberg Eiendom AS | Real estate | 1994 |
| Johan Vinje AS | Real estate | 1990 |
| Johan Vinje Eiendom A/S | Real estate | 1942 |
| Johan Vinje Stål AS | Real estate | 1988 |
| Johanna Invest AS | Financial services | 2006 |
| Johansen Bygg & Rehabilitering AS | Construction | 2016 |
| Johansen Og Brå Invest AS | Financial services | 2016 |
| Johansson Consult AS | Professional & scientific | 2004 |
| Johjoh Holding AS | Financial services | 2016 |
| John Amundsen.Bygg AS | Construction | 2019 |
| John Olav Krogstad AS | Financial services | 2005 |
| Johnhou AS | | 2020 |
| Johnkanon Holding AS | Real estate | 2018 |
| Johnny Love AS | Manufacturing | 2008 |
| Johnsen-Holding AS | Financial services | 2014 |
| Johu Invest AS | Financial services | 2013 |
| Jokkmokk Invest AS | | 2021 |
| Jom AS | Administrative & support | 2010 |
| Jomfrugata 5 AS | Real estate | 2021 |
| Jomfrugt 4 Ans | Real estate | 2005 |
| Jomorgod AS | | 2005 |
| Jon AS | Transport & logistics | 1994 |
| Jon Raudesgate 8 AS | Real estate | 2006 |
| Jonas Follesø AS | Information & communication | 2017 |
| Jonas Paulsen Holding AS | | 2024 |
| Jons Holding AS | | 2022 |
| Jonsvannsv 64 AS | Real estate | 2017 |
| Jonsvannsveien 1 AS | Real estate | 2024 |
| Jonsvannsveien 429 AS | Real estate | 2019 |
| Jonsvannsveien 82 Eiendom AS | Real estate | 2001 |
| Jonsvannsveien AS | Real estate | 2017 |
| Jonsvatnet Grunneierlag SA | Real estate | 2010 |
| Jonsvollskvartalet AS | Real estate | 2001 |
| Jordbærpikene Byhaven AS | Hospitality | 1998 |
| Jordbærpikene Drift AS | Administrative & support | 1998 |
| Jordbærpikene Lade AS | Hospitality | 2013 |
| Jordbærpikene Leangen AS | Hospitality | 2008 |
| Jordbærpikene Solsiden AS | Hospitality | 2000 |
| Jordbærpikene Torget AS | Hospitality | 2004 |
| Jordens Vann Ans | Wholesale & retail | 2002 |
| Jorlo AS | Professional & scientific | 2025 |
| Jormas AS | | 2023 |
| Josef Akademi AS | Education | 2015 |
| Josephsen Holding AS | | 2021 |
| Jostein Bjørkøy Holding AS | Information & communication | 2024 |
| Jotla AS | | 2021 |
| Jotunheimen AS | Arts & recreation | 2020 |
| Jotunheimen Systems AS | Information & communication | 2019 |
| Jotunheimen Trondheim AS | Hospitality | 2021 |
| Journalhjelp AS | Information & communication | 2026 |
| Journalmaler AS | Administrative & support | 2025 |
| Joval AS | | 2026 |
| Jovero AS | Professional & scientific | 2025 |
| Jovien AS | Real estate | 2005 |
| Jovika AS | | 2022 |
| Joyrides AS | Administrative & support | 2012 |