| Igland Storgaten 8 AS | Real estate | 2009 |
| Ikm Preservation AS | Wholesale & retail | 1994 |
| Ikotak AS | Wholesale & retail | 2025 |
| Im Systems AS | Information & communication | 2012 |
| Imer Eiendom AS | Real estate | 2023 |
| Inbuca AS | Professional & scientific | 2010 |
| Industritre AS | Manufacturing | 1999 |
| Industriveien 15 Grimstad AS | Real estate | 2017 |
| Industriveien 36 Ans | Real estate | 1992 |
| Industrivn 17 AS | Real estate | 2020 |
| Innomedic AS | Information & communication | 2022 |
| Innovateur AS | Information & communication | 2020 |
| Innoveide Holding AS | | 2024 |
| Inshare AS | Professional & scientific | 2013 |
| Intechs AS | Professional & scientific | 2013 |
| Interiør-Gården AS | Real estate | 2001 |
| Interlink AS | Wholesale & retail | 1991 |
| Irg Holding AS | | 2019 |
| Isitec AS | Manufacturing | 2015 |
| Isør Prosjekt AS | Professional & scientific | 2020 |
| IT Eiendomsutvikling AS | Real estate | 2011 |
| Itiliti AS | Information & communication | 2016 |
| Ivar Eskedal AS | Real estate | 2018 |
| Iverskjær Ans | Agriculture & fishing | 2016 |
| J - Eiendom AS | Real estate | 2005 |
| J J Ugland AS | Real estate | 1989 |
| J J Ugland Eiendom AS | Real estate | 2024 |
| J J Ugland Holding AS | Transport & logistics | 1987 |
| J P Fysioterapi AS | Health & social care | 2017 |
| J P T Eiendom AS | Real estate | 2008 |
| J P Thygesen AS | Other services | 2001 |
| J-Holding AS | Real estate | 2022 |
| J. B. Ugland Eiendomsforvaltning AS | Real estate | 2012 |
| J. B. Ugland Eiendomsutvikling | Real estate | 2012 |
| J. B. Ugland Holding AS | Construction | 2006 |
| J. B. Ugland Venture AS | Construction | 2001 |
| J. M. Eiendom AS | Real estate | 2003 |
| J.B. Ugland Eiendom AS | Real estate | 2001 |
| J.B. Ugland Eiendom Invest AS | | 2024 |
| J.B. Ugland Entreprenør AS | Construction | 2011 |
| J.B. Ugland Fornybar Energi AS | Energy | 2001 |
| J.B.Ugland AS | Manufacturing | 2006 |
| J.M. Ugland & Co. AS | Real estate | 2005 |
| Jagima Drift AS | Construction | 2012 |
| Jagima Invest Limited Nuf | | 2008 |
| Jagima Norway Ltd Nuf | Real estate | 2008 |
| JB Holding AS | Real estate | 2016 |
| Jbu Grimstad AS | Real estate | 2004 |
| Jbu Kanalbyen AS | Real estate | 2013 |
| Jein AS | Real estate | 2014 |
| Jeine AS | Real estate | 2008 |
| Jer Investeringer AS | Real estate | 2015 |
| Jernbaneveien 221 AS | Real estate | 2026 |
| Jetro AS | Professional & scientific | 1987 |
| Jetro Invest AS | Professional & scientific | 2000 |
| Jfbk Holding AS | Real estate | 2005 |
| Jfloftet AS | Hospitality | 2021 |
| JGL Agro AS | Professional & scientific | 2024 |
| JGS Investment AS | | 2025 |
| JL Eiendom AS | Real estate | 2022 |
| JL Eiendom Holding AS | | 2026 |
| JM Horisont AS | Real estate | 2023 |
| JM Knutsen AS | Information & communication | 2005 |
| JMH Drift AS | Other services | 2026 |
| Joda Industrier AS | Manufacturing | 1986 |
| Joh Gundersen AS | Wholesale & retail | 2003 |
| Johannes Skar AS | | 2024 |
| John Nilsen AS | Real estate | 2007 |
| John Rasmussen Invest AS | Real estate | 2008 |
| Johna Holding AS | | 2021 |
| Johnsen Konsulenttjenester AS | Professional & scientific | 2016 |
| Joj Service AS | Administrative & support | 2025 |
| Joja AS | Financial services | 2005 |
| Jojo Invest AS | Real estate | 2011 |
| Jon Lilletuns Vei 1 AS | Real estate | 2012 |
| Jon Lilletuns Vei 3 AS | Real estate | 2012 |
| Jon Lilletuns Vei 5 AS | Real estate | 2018 |
| Jon Lilletuns Vei 7 AS | Real estate | 2021 |
| Jon Lilletuns Vei 9 AS | Real estate | 2012 |
| Jon Lilletunsvei 3B AS | Real estate | 2020 |
| JTS Consults AS | Administrative & support | 2025 |
| Judo AS | Information & communication | 2025 |
| Junami Invest AS | | 2008 |
| Jørgen Bangsgate 7 AS | Real estate | 2006 |
| Jørgensen Malerservice Grimstad AS | Construction | 2020 |
| K G Puntervold AS | Manufacturing | 1976 |
| K. a. Dyvik A/S | Professional & scientific | 2016 |
| K.Andersson AS | Professional & scientific | 2021 |
| K.E. Montasje AS | Real estate | 2013 |
| K2 Gründerlab AS | Professional & scientific | 1998 |
| Kaldvellfjorden Eiendom AS | Real estate | 2015 |
| Kamp Capital AS | | 2025 |
| Kanaan AS | Real estate | 1991 |
| Karlsen Og Co Holding AS | Construction | 2023 |
| Karrierevei Kurs AS | Wholesale & retail | 2016 |
| Kaup Invest AS | | 2024 |
| Kerlic Holding AS | Financial services | 2017 |
| KGH Eiendom Og Drift AS | Real estate | 2024 |
| KGH Helse AS | Health & social care | 2024 |
| KGH Holding AS | Real estate | 2023 |