| Inpernova AB | Se-451 75 Uddevalla | 2016 |
| Inphase Solutions AS | Trondheim | 2019 |
| Inplena AS | Nesodden | 2017 |
| Inpoint Da | Oslo | 2010 |
| Inprocess Project Consulting AS | Asker | 2019 |
| Inpublic AS | Gjøvik | 2017 |
| Inquire AS | Asker | 2010 |
| Inquire Holding AS | Asker | 2010 |
| Inregnico AS | Etnedal | 2017 |
| Inrigo AS | Heimdal | 2018 |
| Inrigo Holding AS | Heimdal | 2018 |
| Inrs AS | Snarøya | 2025 |
| Insa Advokater AS | Oslo | 2019 |
| Insala AS | Nesoddtangen | 2020 |
| Insam AS | Drammen | 2006 |
| Insane Architects AS | Hamar | 2023 |
| Inscan AS | Greåker | 2023 |
| Insea Quality Services AS | Skage I Namdalen | 1992 |
| Insel Engineering AS | Hyggen | 1991 |
| Insenti AS | Oslo | 2010 |
| Insenti Holding AS | Oslo | 2014 |
| Insenti Samferdsel AS | Oslo | 2015 |
| Inseo AS | Fyllingsdalen | 2025 |
| Insert Solution AS | Lier | 2002 |
| Inservio AS | Ulsteinvik | 2013 |
| Insha AS | Hundvåg | 2022 |
| Inshare AS | Grimstad | 2013 |
| Insi AS | Kvaløysletta | 2007 |
| Inside Design AS | Oslo | 2025 |
| Inside Out Consulting AS | Snarøya | 2019 |
| Inside Sport AS | Mysen | 2013 |
| Insight Advisors AS | Oslo | 2024 |
| Insight AS | Flekkerøy | 2018 |
| Insight Consulting AS | Fana | 2016 |
| Insight Group Da | Kurland | 1999 |
| Insight Management AS | Stavanger | 2025 |
| Insight NDT Ike Nuf | Gr-18452 Nikea | 2024 |
| Insight Regnskap AS | Oslo | 2014 |
| Insight Sales AS | Trondheim | 2015 |
| Insightone Nordic AS | Oslo | 1992 |
| Insightsoftware Norway AS | Oslo | 2004 |
| Insignis AS | Oslo | 2016 |
| Insigto AS | Oslo | 2018 |
| Insikta AS | Årnes | 2011 |
| Insilent AS | Oslo | 2019 |
| Insitor AS | Bergen | 2017 |
| Insola AB | Oslo | 2011 |
| Insolidum AS | Drammen | 2015 |
| Insourcing Services AS | Fetsund | 2008 |
| Inspe Consulting AS | Oslo | 2021 |
| Inspect AS | Drammen | 2021 |
| Inspect Elektro AS | Tønsberg | 2020 |
| Inspect Energi AS | Drammen | 2023 |
| Inspect Innbo AS | Drammen | 2012 |
| Inspect Legal AS | Drammen | 2023 |
| Inspecterra Norway AS | Sandnes | 2019 |
| Inspectia AS | Sandnes | 2017 |
| Inspection AS | Leksvik | 2020 |
| Inspection Subsea Ltd | Blairgowrie Ph11 8Bg Scotland | 2019 |
| Inspection Works AS | Fornebu | 2022 |
| Inspectmar AS | Molde | 2014 |
| Inspekt Alfatest AB Nuf | Se-261 51 Landskrona | 2018 |
| Inspekt Molab AS | Mosjøen | 2023 |
| Inspekt Norway AS | Mosjøen | 2023 |
| Inspekt Welding Partner Nordic AB | Se-695 32 Laxå | 2025 |
| Inspektion-Tjenester AS | Risør | 2021 |
| Insperia AS | Nøtterøy | 2004 |
| Inspira Interiørkontor AS | Horten | 2020 |
| Inspirante AS | Oslo | 2018 |
| Inspirasail AS | Kristiansund N | 2018 |
| Inspire (Structures) Ltd Nuf | Yo13 9Ae North Yorkshire | 2021 |
| Inspire AS | Høvik | 2000 |
| Inspire Energy Solutions AS | Høvik | 2024 |
| Inspire Invest AS | Høvik | 1990 |
| Inspire Life AS | Fagerstrand | 2025 |
| Inspire Nordic AS | Søgne | 2026 |
| Inspirica AS | Vikersund | 2017 |
| Inspirida Consulting AS | Rygge | 2019 |
| Inspirit Da | Bardufoss | 2002 |
| Inspo Interiør AS | Drammen | 2022 |
| Inst-Strum Limited | Stockton-On-Tees Ts23 3Ud | 2024 |
| Instabox Group AB Nuf | Se-113 43 Stockholm | 2023 |
| Instal-Filter Industrial Air Protection Systems | Pl-64-000 Koscian | 2024 |
| Instalco Norge AS | Hvalstad | 2024 |
| Installasjon & Driftsteknikk AS | Oslo | 2012 |
| Instanes AS Rådgivende Ingeniører | Nesttun | 1983 |
| Instant Iris AS | Bergen | 2023 |
| Instant Memory AS | Stabekk | 2023 |
| Instaraising AS | Åsgårdstrand | 2024 |
| Instat AS | Trondheim | 1989 |
| Instatera AS | Skreia | 2021 |
| Inste Kneppen AS | Oslo | 2005 |
| Instel AS | Tyssedal | 2018 |
| Institut DR. Foerster GmbH & Co. KG | De-72766 Reutlingen | 2021 |
| Institut Francais De Norvege | Oslo | 1995 |
| Institute of Computer Science | Cz-182 00 Prague 8 | 2025 |
| Institute of Nordic Mediation AS | Oslo | 2025 |
| Institutt for Bedriftssikring AS | Kristiansand S | 1996 |
| Institutt for Handelsanalyser AS | Oslo | 1992 |
| Institutt for Ledelse Og Administrasjon AS | Hjellestad | 1987 |