| Jaegert Holding AS | | 2025 |
| Jaer Holding AS | | 2025 |
| Jaer Invest AS | | 2025 |
| Jafe Invest AS | Health & social care | 2005 |
| Jaff Gruppen AS | Administrative & support | 2016 |
| Jag Assistanse AS | Health & social care | 2010 |
| Jaga Jazzist AS | Arts & recreation | 2000 |
| Jagger Burger Oslo AS | Hospitality | 2024 |
| Jagger Junk Oslo AS | Hospitality | 2022 |
| Jagima Eiendom AS | Real estate | 2012 |
| Jagima Gruppen AS | Real estate | 2012 |
| Jagoda AS | Real estate | 2001 |
| Jaguar Capital AS | | 2022 |
| Jah AS | Real estate | 2008 |
| Jah Consult & Invest AS | Information & communication | 2022 |
| Jaha Capital AS | Financial services | 2013 |
| Jaha Holding AS | Real estate | 2013 |
| Jahalst AS | Professional & scientific | 2015 |
| Jahan Islam Invest AS | | 2024 |
| Jahbility AS | | 2019 |
| Jaholmen AS | | 2021 |
| Jahr & Døtre AS | | 2022 |
| Jahr & Sønner Ans | Real estate | 1989 |
| Jahr & Sønner AS | Real estate | 2022 |
| Jahr Eiendomsselskap AS | Real estate | 2022 |
| Jahr Finans AS | Real estate | 2018 |
| Jahr Gruppen AS | Real estate | 2018 |
| Jahr Invest AS | Real estate | 2017 |
| Jahr Næringseiendom AS | Real estate | 2018 |
| Jahr Omsorgsbolig AS | Real estate | 2025 |
| Jahre Eiendom AS | Real estate | 2005 |
| Jahren Holding AS | Real estate | 2007 |
| Jahren Invest AS | Financial services | 2014 |
| Jahrmann AS | Financial services | 2005 |
| Jai AS | | 2021 |
| Jai Holding AS | | 2024 |
| Jaja Architects Nuf | Professional & scientific | 2023 |
| Jaja Holding AS | | 2024 |
| Jaja Invest AS | | 2019 |
| Jajaja AS | Hospitality | 2013 |
| Jaje Holding AS | | 2020 |
| Jajim AS | | 2019 |
| Jajo AS | Transport & logistics | 2007 |
| Jajo Holding AS | | 2019 |
| Jajoin AS | Financial services | 2012 |
| Jak AS | Professional & scientific | 2016 |
| Jak Invest AS | | 2018 |
| Jakam AS | Real estate | 2020 |
| Jakbr Holding AS | | 2024 |
| Jakfa Invest AS | Real estate | 2013 |
| Jakin Invest AS | Financial services | 2006 |
| Jako AS | Wholesale & retail | 1949 |
| Jakob AS | Professional & scientific | 1996 |
| Jakob Håkon AS | Professional & scientific | 2023 |
| Jakobgm AS | | 2022 |
| Jakobsen Frukt & Grønt AS | Professional & scientific | 2020 |
| Jakobsen Insulting AS | | 2023 |
| Jakobsen Tunez AS | Information & communication | 2025 |
| Jakobsliveien 57 AS | Real estate | 2020 |
| Jakobsliveien 59 A/B AS | Real estate | 2020 |
| Jakra AS | Real estate | 2019 |
| Jakro AS | Wholesale & retail | 2024 |
| Jakslandåsen AS | Real estate | 2017 |
| Jakslandåsen Boligutvikling AS | Real estate | 2020 |
| Jakt & Fiske Holdco AS | Professional & scientific | 2022 |
| Jaktlia 19 Eiendom AS | Real estate | 2023 |
| Jaktlia Utvikling AS | Real estate | 2022 |
| Jaktutvalget AS | Education | 2021 |
| Jakvi AS | Real estate | 1994 |
| Jal AS | Professional & scientific | 2019 |
| Jal II AS | | 2021 |
| Jalborgs Gode Greier AS | Information & communication | 2021 |
| Jalil AS | Information & communication | 2020 |
| Jalmaus Invest AS | Real estate | 2011 |
| Jalomi AS | Agriculture & fishing | 2005 |
| Jalqan Fashion Shop AS | Wholesale & retail | 2025 |
| Jalse Holding AS | Financial services | 2005 |
| Jalut Holdings AS | | 2023 |
| Jalvad AS | Wholesale & retail | 1973 |
| Jam AS | Health & social care | 2007 |
| Jam Egnatia AS | | 2025 |
| Jama AS | Hospitality | 1995 |
| Jama Holding AS | Real estate | 2005 |
| Jamami Invest AS | Financial services | 2005 |
| Jaman AS | Financial services | 2005 |
| Jamar Holding AS | | 2026 |
| Jamar Prosjekt AS | Professional & scientific | 2026 |
| Jamatito Invest AS | Financial services | 2005 |
| Jambo Eiendom AS | Real estate | 2003 |
| James a AS | | 2018 |
| James Andersen Invest Ltd Nuf | Real estate | 2007 |
| James Grønn Investering AS | | 2022 |
| James Larsen Invest AS | Financial services | 2016 |
| James Walker Norge AS | Manufacturing | 1999 |
| Jamlet AS | | 2025 |
| Jampe AS | Financial services | 2005 |
| Jan & Terjes Verksted Da | Other services | 1993 |
| Jan Ballangrud Pensjons- Og Forsikringsrådgivning AS | Professional & scientific | 2024 |
| Jan Barbershop AS | Other services | 2023 |
| Jan Egil Krefting AS | Financial services | 2016 |