| Hwox AS | | 2025 |
| Hydema AS | Manufacturing | 1977 |
| Hydroclean AS | Water & waste | 2011 |
| Hydroclean Vilda AS | Real estate | 2016 |
| Hyfe Wind 2 AS | Energy | 2015 |
| Hyfe Wind 4 AS | Professional & scientific | 2017 |
| Hyllemor AS | Construction | 2023 |
| HZ Agentur AS | Wholesale & retail | 2013 |
| Hamax AS | Wholesale & retail | 1958 |
| Håndverker Hansen AS | Construction | 2011 |
| Håndverksenteret AS | Real estate | 2002 |
| Hårkunst AS | Other services | 2025 |
| Hårologi of Sweden AB Nuf | Wholesale & retail | 1995 |
| Högbergs Service AS | Information & communication | 2024 |
| Høiden Bilpleie AS | | 2013 |
| Høiden Bilverksted AS | Other services | 1993 |
| Høienhald Invest AS | Real estate | 2006 |
| Høienhaldgata 4 AS | Real estate | 2008 |
| Høst Tattoo AS | Other services | 2021 |
| Høyden Hår Og Skjønnhetspleie AS | Wholesale & retail | 2013 |
| Høyt Nivå AS | Administrative & support | 2020 |
| I All Enkelhet Formidling AS | Health & social care | 2018 |
| I&D Maler AS | Construction | 2016 |
| I&J Holding AS | Information & communication | 2016 |
| I.E.H. Holding AS | Wholesale & retail | 2023 |
| Iag Business Solutions AS | Professional & scientific | 2025 |
| Iag Holding AS | Wholesale & retail | 2018 |
| Ibs Security AS | Wholesale & retail | 1986 |
| Icogito AS | | 2020 |
| Icon Events Da | Administrative & support | 2017 |
| Ideco AS | Real estate | 2006 |
| Ideco Bygg AS | Construction | 2020 |
| Ideco Invest AS | | 2020 |
| Idrettsservice AS | Other services | 2026 |
| Iflow AS | Information & communication | 2022 |
| Ihc Networks AB | Information & communication | 2010 |
| Iin Holding AS | Wholesale & retail | 2025 |
| Ikon Ideea Nuf | Manufacturing | 2024 |
| Ila Alle 48 AS | Real estate | 2019 |
| Ilaria AS | Wholesale & retail | 2022 |
| Ille AS | Hospitality | 2013 |
| Imena Holding AS | | 2025 |
| In Situ AS | Professional & scientific | 2008 |
| In-Bo Haug AS | Wholesale & retail | 1971 |
| Indent AS | Information & communication | 2022 |
| Industrikonsulenten Moss AS | Financial services | 2006 |
| Inneklimateknikk AS | Wholesale & retail | 1990 |
| Innovative Gaming Solutions AS | Information & communication | 2009 |
| Innovent 1 AS | Real estate | 2024 |
| Innovision AS | Real estate | 2003 |
| Inor Invest AS | Information & communication | 2018 |
| Intactor AS | Professional & scientific | 2015 |
| Inter Trade Nor Safe-Tec AS | Wholesale & retail | 1998 |
| Interaction Development AS | Education | 1998 |
| Inventuro Holding AS | | 2019 |
| Investorprosjekt Lxvi AS | Financial services | 2007 |
| Invita AS | Professional & scientific | 2013 |
| Iqbal Svinndal AS | Hospitality | 2011 |
| Iranor Holding AS | | 2026 |
| Iris Syn AS | Health & social care | 2025 |
| Isac Capital AS | | 2025 |
| Isak Eiendom AS | Real estate | 2016 |
| Isazi Consulting AS | Professional & scientific | 2005 |
| Isegran Invest AS | | 2021 |
| Ishall I Moss AS | Arts & recreation | 2005 |
| Iskilt AS | Professional & scientific | 2024 |
| Islandspesialisten AS | Administrative & support | 2011 |
| Isopartner AS | Wholesale & retail | 1991 |
| Istanbul Restaurant Moss AS | Hospitality | 2024 |
| IT Cloud AS | Information & communication | 2020 |
| IT Development AS | Information & communication | 2012 |
| IT Kopiteknikk AS | Wholesale & retail | 2025 |
| Itd Eiendom AS | Real estate | 2016 |
| Itd Holding AS | Wholesale & retail | 1994 |
| Ivar Nilsen Eiendom AS | Real estate | 2003 |
| Ivar Nilsen Entreprenør AS | Construction | 1996 |
| J & W Venture AS | | 2026 |
| J a Magnussen Drift AS | Wholesale & retail | 1995 |
| J a Magnussen Engros AS | Wholesale & retail | 1985 |
| J Hult Byggnadsfirma | Construction | 2002 |
| J Island Wine AS | Wholesale & retail | 2017 |
| J Lykke T Invest AS | | 2025 |
| J-Boats Norge AS | Wholesale & retail | 2018 |
| J28 Holding AS | Real estate | 2019 |
| Ja Hodl AS | Information & communication | 2024 |
| Jac Holding AS | Construction | 2017 |
| Jacobsen Group AS | | 2023 |
| Jagu Eienom Da | Real estate | 2005 |
| Jak J Alveberg AS | Wholesale & retail | 1967 |
| Jakita Holding AS | Real estate | 2006 |
| Jalund Holding AS | Other services | 2022 |
| Jan E. Fjell Flis Og Mur AS | Construction | 2014 |
| Jan Ellefsen Consulting AS | | 2020 |
| Janson Bridging Norway AS | Administrative & support | 2014 |
| Jansson Invest AS | | 2023 |
| Jape Produkter AS | Professional & scientific | 2022 |
| Jarle Groth Invest AS | Financial services | 2005 |
| Jarle Unnerud AS | Construction | 1988 |
| Jas Worldwide Norway AS | Transport & logistics | 1980 |
| JBF Holding AS | Financial services | 2015 |