| Inovativ Bygg AS | Construction | 2023 |
| Inovera AS | Education | 2015 |
| Insta Auto AS | Wholesale & retail | 2022 |
| Intakt Bilskade Mo I Rana AS | Other services | 1995 |
| Interiør & Innredning AS | Wholesale & retail | 2011 |
| Intracloud AS | Information & communication | 1995 |
| Inur AS | Health & social care | 2022 |
| Iras Holding AS | | 2024 |
| Irish Red Invest AS | Real estate | 2010 |
| Ironic Invest AS | | 2021 |
| Isaxa Frisør AS | Other services | 2005 |
| Isority AS | | 2024 |
| It-Smurfan AS | Information & communication | 2023 |
| J T Brattli Byggservice AS | Construction | 2001 |
| J. Jacobsen Transport AS | Transport & logistics | 2012 |
| J.Børstad Holding AS | | 2026 |
| J.Larsen AS | Administrative & support | 2019 |
| Jamtjord Maskin Og Anlegg AS | Construction | 2015 |
| JBF Eiendom AS | Real estate | 2017 |
| JBF Invest AS | Real estate | 1997 |
| Jean Greim AS | Real estate | 2007 |
| Jern & Maskin AS | Other services | 2011 |
| Jern & Maskin Eiendom AS | Other services | 2011 |
| Jern & Maskin Holding AS | Other services | 2011 |
| Jernbanegata 18 AS | Real estate | 2013 |
| Jim Sandberg AS | | 2012 |
| Jina AS | Health & social care | 2021 |
| JKJ Transport AS | Construction | 2023 |
| Jkrb Holding AS | | 2018 |
| JM Data System AS | Information & communication | 1994 |
| JM Kapital AS | Real estate | 2008 |
| JM Kontor AS | Wholesale & retail | 2014 |
| Jma Bygg AS | Construction | 2026 |
| Jma Eiendom AS | Real estate | 2022 |
| Jma Holding AS | Health & social care | 2021 |
| JMD Eiendom AS | Real estate | 2004 |
| JMD Holding AS | Information & communication | 2005 |
| Joar's Musikkservice AS | Wholesale & retail | 2009 |
| Johansen Og Nicolaisen Ans | Construction | 1996 |
| Johansen Transport AS | Transport & logistics | 1994 |
| Johs. Monsen Holding AS | Real estate | 2005 |
| Jord:Nær Arkitektur AS | Professional & scientific | 2018 |
| Jov Holding AS | | 2020 |
| Juliannes Rammeverksted AS | Manufacturing | 2017 |
| Just Wright AS | | 2023 |
| K Betong AS | Construction | 2024 |
| K J Karlsen Eiendom AS | Real estate | 1979 |
| K J Karlsen AS | Wholesale & retail | 2002 |
| K. Hansen Rørservice AS | Construction | 2019 |
| K2 Mo AS | Real estate | 2014 |
| K2 Mo Bolig AS | Real estate | 2021 |
| Kaialund Eiendom AS | Real estate | 2017 |
| Kaialundveien AS | Real estate | 2020 |
| Kalsarikännit AS | | 2025 |
| Kalvik Holding AS | Real estate | 2017 |
| Kamjo Holding AS | | 2021 |
| Kanaltomta AS | Real estate | 2013 |
| Kapitalforvaltning Nord AS | Financial services | 2014 |
| Kaspersen & Einhaug AS | Administrative & support | 2022 |
| Kasuma AS | Construction | 2015 |
| Kathhama Holding AS | Real estate | 1993 |
| Katrine.I.Nord AS | Wholesale & retail | 2022 |
| KB Rana Eiendom AS | Real estate | 2023 |
| Kbi Holding AS | Financial services | 2012 |
| KE0 Holding AS | | 2021 |
| Kera Invest AS | Financial services | 2024 |
| Ketil Steinbakk Holding AS | Financial services | 2013 |
| Kfsb Holding AS | Administrative & support | 2022 |
| Kfsb Utleie AS | Administrative & support | 2023 |
| Kibsgaard Invest AS | Professional & scientific | 2016 |
| Killi Service AS | Construction | 2015 |
| Kingdom Lifestyle AS | Education | 2015 |
| Kintuck AS | Manufacturing | 2011 |
| Kisveien AS | Real estate | 2020 |
| Kjemphei Naturgrus AS | Construction | 1995 |
| Kjernen Eiendom AS | Real estate | 2019 |
| Kjerrvang Eiendom Ans | Real estate | 1995 |
| Kjøkkendrift No 1 Mo I Rana AS | Wholesale & retail | 2011 |
| KL Property AS | Professional & scientific | 2024 |
| Klaebo Vonstad Holding AS | Professional & scientific | 2019 |
| Klaff AS | Administrative & support | 2012 |
| Klaff Holding AS | Administrative & support | 2017 |
| Kling AS | Information & communication | 2024 |
| Klinikk Helgeland AS | Health & social care | 2012 |
| Klink Invest AS | | 2025 |
| Klosterskogen Hage Og Parkanlegg AS | Agriculture & fishing | 2020 |
| KMD Holding AS | Real estate | 2006 |
| Kobolt AS | Professional & scientific | 2026 |
| Kokfesk Invest AS | | 2025 |
| Koksverksgata 10 AS | Real estate | 2024 |
| Kolstad Økonomistyring AS | Professional & scientific | 2012 |
| Kommune Analyse AS | Professional & scientific | 2026 |
| Kompetanse Holding AS | Financial services | 1993 |
| Kona AS | Real estate | 2018 |
| Kongkav AS | Professional & scientific | 2023 |
| Kongsparken AS | Real estate | 2020 |
| Kooperativen Kjøpesenter AS | Real estate | 2010 |
| Korsnes Liu Holding AS | Hospitality | 2024 |
| KR Svendsen AS | Construction | 1969 |
| Kraft Dansestudio AS | Education | 2015 |