| Jernbanegata Eiendomsutvikling AS | Real estate | 2019 |
| Jernbanegaten 6 Kongsvinger AS | Real estate | 2002 |
| Jernbanetorget 2 AS | Real estate | 2011 |
| Jernbanetorget 2 Da | Real estate | 1992 |
| Jernbanetorget 4 AS | Real estate | 2013 |
| Jernbaneveien 1 AS | Real estate | 2021 |
| Jernbaneveien 11 Utvikling AS | Real estate | 2021 |
| Jernbaneveien 1A AS | Real estate | 2014 |
| Jernbaneveien 24 AS | Real estate | 2017 |
| Jernbaneveien 27 AS | Real estate | 2006 |
| Jernbaneveien Eiendom AS | Real estate | 2019 |
| Jernbaneveien Utvikling AS | Real estate | 2018 |
| Jernberg-Hauge AS | Financial services | 2018 |
| Jernimport AS | Financial services | 2007 |
| Jernkroken 18 AS | Real estate | 2023 |
| Jernkroken Næringsbygg AS | Real estate | 2006 |
| Jerntomta AS | Real estate | 2016 |
| Jerntomta Holding AS | Real estate | 2016 |
| Jerntomta Holding II AS | | 2025 |
| Jerntomta Holding III AS | | 2025 |
| Jerntomta Holding IV AS | | 2025 |
| Jero Holding AS | Information & communication | 2005 |
| Jerome Lacoste AS | Hospitality | 2019 |
| Jerp Holding AS | | 2021 |
| Jerpefaret 12 AS | Real estate | 2021 |
| Jerss Sena Jern Og Metall AS | Wholesale & retail | 2022 |
| Jerveskar AS | Financial services | 2005 |
| Jes-Jm Holding AS | | 2020 |
| Jesel Da | Wholesale & retail | 1991 |
| Jeshua AS | Administrative & support | 2024 |
| Jesper Invest AS | | 2020 |
| Jesper T. Knutsen Trafikkskole AS | Education | 2024 |
| Jessheim B4.1 Utvikling AS | Real estate | 2022 |
| Jessheim B6.5 AS | Real estate | 2019 |
| Jessheim B6.5 Holding AS | Real estate | 2023 |
| Jessheim Bil Holding AS | Real estate | 2016 |
| Jessheim Eiendom AS | Real estate | 2015 |
| Jessheim Eiendomsutvikling AS | Real estate | 2014 |
| Jessheim Forretningseiendom Ans | Real estate | 2002 |
| Jessheim II AS | Real estate | 2017 |
| Jessheim Kolonial Og Trim AS | Real estate | 2025 |
| Jessheim Live AS | Arts & recreation | 2025 |
| Jessheim Living Holding AS | | 2024 |
| Jessheim Nord AS | Real estate | 2017 |
| Jessheim Næringspark AS | Real estate | 2016 |
| Jessheim Næringspark Invest AS | Real estate | 2021 |
| Jessheim Sentrum AS | Real estate | 2017 |
| Jessheim Sentrum Invest AS | Real estate | 2014 |
| Jessheim Sentrumseiendom AS | Real estate | 2021 |
| Jessheim Storhandel AS | Real estate | 2024 |
| Jessheim Storsenter AS | Real estate | 1998 |
| Jessheim Sør Næring AS | Real estate | 2017 |
| Jessheim Utvikling AS | Real estate | 2017 |
| Jessheim Vann Og Brød AS | Real estate | 2002 |
| Jessnesvegen 656 AS | Real estate | 2021 |
| Jesting Eiendomsservice AS | Construction | 2006 |
| Jesting Sport AS | Wholesale & retail | 1967 |
| Jesus People AS | Other services | 2022 |
| Jetas AS | | 1964 |
| Jetfly AS | | 2007 |
| Jetfrig AS | Financial services | 2012 |
| Jethart AS | Wholesale & retail | 2010 |
| Jeton AS | Professional & scientific | 2019 |
| Jetor AS | Real estate | 2018 |
| Jets Invest AS | | 2019 |
| Jetset Go AS | Wholesale & retail | 2025 |
| Jett Holding AS | | 2026 |
| Jette Invest AS | | 2021 |
| Jetties Advisory AS | Professional & scientific | 2025 |
| Jev Invest AS | | 2006 |
| Jevanord AS | Wholesale & retail | 1923 |
| Jevebo Garasjelag 1 SA | Real estate | 1997 |
| Jevebo Garasjelag 2 SA | Real estate | 1968 |
| Jevi Holding AS | | 2021 |
| Jevne Invest AS | | 2024 |
| Jewel AS | Hospitality | 2022 |
| Jewel Invest AS | Real estate | 2009 |
| Jewel of India AS | Hospitality | 2005 |
| Jewelmade AS | Arts & recreation | 2025 |
| Jewl Invest AS | | 2026 |
| Jezet Seating NV | Manufacturing | 2012 |
| JF Capital AS | | 2025 |
| Jf-K AS | Professional & scientific | 2010 |
| Jfbg AS | Financial services | 2008 |
| JFD Økonomi AS | Professional & scientific | 2013 |
| Jfeh Holding AS | | 2022 |
| JFG Eiendom AS | Real estate | 2016 |
| JFG Holding AS | | 2024 |
| JFH Invest 1 AS | | 2021 |
| JFH Invest 2 AS | | 2021 |
| JFH Invest 3 AS | | 2021 |
| Jfi Eiendom Og Vedlikehold AS | Real estate | 2018 |
| JFK Invest AS | Financial services | 2017 |
| JFL Holding AS | Wholesale & retail | 2016 |
| JFL Kapital AS | | 2025 |
| JFL VR AS | Information & communication | 2025 |
| JFM Holding AS | | 2021 |
| JFP III AS | Wholesale & retail | 2008 |
| JFP Invest AS | Professional & scientific | 2013 |
| JFP Invest II AS | | 2018 |