| Holberg Eiendom AS | Real estate | 1966 |
| Holøyen AS | Wholesale & retail | 2012 |
| Hommelvik Sjøside AS | Real estate | 2007 |
| Hommelvik Sjøside Bolig AS | Real estate | 2006 |
| Hommelvik Sjøside Moan AS | Real estate | 2013 |
| Hommelvik Sjøside Næring AS | Real estate | 2011 |
| Hos Marit AS | Other services | 2007 |
| Hougen Invest AS | | 2001 |
| Hre Holding AS | Financial services | 2005 |
| Hsse Eiendom AS | Real estate | 2011 |
| Hudlegekontoret Steinkjer AS | Health & social care | 2022 |
| Hugin Eiendomsutvikling AS | Real estate | 1997 |
| Hus Og Sånt AS | Real estate | 2025 |
| Husby Optikk AS | Wholesale & retail | 1990 |
| Husbygg Steinkjer AS | Construction | 2016 |
| Husfliden AS | Wholesale & retail | 1980 |
| Huvhpie AS | Real estate | 2012 |
| HW Utvikling AS | Health & social care | 2011 |
| Håkkagata Eiendom AS | Real estate | 2006 |
| Håkkågata 1 AS | Real estate | 2005 |
| Hårgalleriet Saxo AS | Other services | 1997 |
| Hårsentret AS | Other services | 1991 |
| Håvard Belbo AS | Real estate | 2014 |
| Høvdinggården AS | Real estate | 2003 |
| Høvdinggården Gym Og Fysioterapi AS | Arts & recreation | 2015 |
| Høvdinggården Legekontor AS | Health & social care | 2010 |
| Høy & Rodum Eiendom AS | Real estate | 1956 |
| I. J. Regnskap AS | Professional & scientific | 2013 |
| Icepack Norway AS | Wholesale & retail | 2016 |
| Ichiban AS | Financial services | 2004 |
| Ida's Gravstell Da | Other services | 2021 |
| IDE-HJØRNET HOBBY OG SYSTUE DA Solfrid Bratberg Holan og Vigdis Vesterdal Lillemark | Manufacturing | 1989 |
| Illern AS | | 2006 |
| Inderøy Taxi AS | Transport & logistics | 2018 |
| Informatiker AS | Information & communication | 2019 |
| Infrascan AS | Professional & scientific | 2026 |
| Inge Krokstad Invest AS | | 2024 |
| Ingmar Holding AS | Professional & scientific | 2010 |
| Inn På Homnes Tun AS | Health & social care | 2022 |
| Inn På Tunet Trøndelag SA | Other services | 2006 |
| Innfrakt AS | Transport & logistics | 2024 |
| Innherred Førstehjelp Da | Education | 2015 |
| Innherred Landbrukstjenester SA | Agriculture & fishing | 1982 |
| Innherred Prosjekt AS | Professional & scientific | 2026 |
| Innocamp AS | Real estate | 1987 |
| Innohub AS | Real estate | 2018 |
| Innovation & Design Technology AS | Manufacturing | 2015 |
| Inntre Eiendom AS | Real estate | 2003 |
| Inntre Energi AS | Energy | 1950 |
| Inntre Energi Holding AS | Real estate | 2013 |
| Inntre Energi Steinkjer AS | Energy | 2013 |
| Inntre Holding AS | Manufacturing | 2003 |
| Inntre Kjeldstad AS | Manufacturing | 2003 |
| Inntrøndelag Antikk Og Auksjon AS | Wholesale & retail | 2018 |
| Intakt Bilskade Steinkjer AS | Other services | 1997 |
| Interactive Training Company Ans | Education | 2003 |
| Interaktiv Markedsføring AS | Professional & scientific | 2023 |
| IT Team Ans | Information & communication | 2001 |
| IVE9 AS | Real estate | 2014 |
| J & R Invest AS | Real estate | 2022 |
| Jaggu AS | Construction | 2024 |
| Jakt Og Fangstbua Ans | Wholesale & retail | 1994 |
| Jakt Og Fangstbua AS | Wholesale & retail | 2001 |
| Jamt AS | | 2025 |
| Jan Olav Haugbotn Holding AS | Financial services | 2016 |
| Jardin Holding AS | | 2022 |
| Jeanettes Holding AS | Other services | 2020 |
| Jeanor AS | Construction | 2005 |
| Jens Kvernmo AS | Information & communication | 2021 |
| Jens Ole & Tonje Holdco AS | | 2024 |
| Jenshus Eiendom AS | Real estate | 1998 |
| Jenssen Og Pedersen AS | Transport & logistics | 2023 |
| Jenssen Transport AS | Transport & logistics | 2018 |
| Jevig Holding AS | | 2023 |
| Jimsa Holding AS | Financial services | 2014 |
| JL All Lakk & Reparasjon AS | Other services | 2018 |
| JM Hansen Midt AS | Construction | 2007 |
| JM Trana Eiendom AS | Real estate | 2021 |
| JM Trana Holding AS | Real estate | 2005 |
| JMT Bygg AS | Construction | 2019 |
| Jofe Holding AS | Construction | 2021 |
| Joker Kontor & Data AS | Wholesale & retail | 1995 |
| Jonsrud Invest AS | Real estate | 2012 |
| Jordbærpikene Steinkjer AS | Hospitality | 2008 |
| JS Import AS | Wholesale & retail | 2006 |
| Just Store AS | Transport & logistics | 2022 |
| Jæktskippergata 8 AS | Real estate | 2007 |
| Jæktskippergata Eiendom AS | Real estate | 2004 |
| Jæktsmedgata 4 AS | Real estate | 2020 |
| Jæktsmedgata Eiendom AS | Real estate | 2015 |
| Jørum Kompetanse AS | Administrative & support | 2022 |
| Jægtvolden A/S | Real estate | 1983 |
| K&K Service AS | Construction | 2022 |
| K. Nikolaisen AS | Wholesale & retail | 2020 |
| K.A Kapital AS | | 2025 |
| K.J.R. Holding AS | Mining & quarrying | 2005 |
| K8 Cocktailbar AS | Hospitality | 2024 |
| K8 Holding AS | Transport & logistics | 2020 |
| Kakskiv AS | Manufacturing | 2024 |
| Kame Eiendom AS | Real estate | 2022 |