| Infosørbygget AS | His | 1999 |
| Infotakst AS | Kristiansand S | 2026 |
| Infoteam AS | Oslo | 1982 |
| Infotrend Estate AS | Trondheim | 1999 |
| Infra Eiendom AS | Stavanger | 2025 |
| Infraheim AS | Oslo | 2018 |
| Infraheim Eldre AS | Oslo | 2025 |
| Infraheim Enebolig AS | Oslo | 2021 |
| Infranett AS | Molde | 2005 |
| Infranode AB | Oslo | 2018 |
| Infraparken AS | Tvedestrand | 2019 |
| Infrastrukturfond Eggedal SA | Eggedal | 2021 |
| Infront Utvikling AS | Tromsdalen | 2019 |
| Infuturo Forvaltning AS | Ålgård | 2019 |
| Infuturo Invest AS | Ålgård | 2021 |
| Ing Kjell a Sletten AS | Skien | 1994 |
| Ing Norsted AS | Halden | 1997 |
| Ing Rybergsgate 48 AS | Drammen | 2015 |
| Ing S Lindeberg AS | Lillesand | 1975 |
| Ing. a Magnussen Invest AS | Kabelvåg | 2011 |
| Ing. Arve Eid Ans | Oslo | 2005 |
| Ing. G Holte AS | Oslo | 2004 |
| Ing. Geir Kilmark AS | Tromsø | 2007 |
| Ing. Hvassing AS | Bodø | 2009 |
| Ing. Jan N. Endresen AS | Røyksund | 2005 |
| Ing. Ludvigsens GT. 24 AS | Drammen | 2016 |
| Ing. Pål-H Degnes AS | Sarpsborg | 2021 |
| Ing. Rybergsgate 102 AS | Drammen | 2012 |
| Ing. Rybergsgt. 56 AS | Nesbru | 2005 |
| Ing. Øyvind Isaksen AS | Skjervøy | 2008 |
| Inga Scheitz Holding AS | Oslo | 2023 |
| Ingalill Høstmælingen Eiendom Ans | Gullaug | 2003 |
| Ingar Dalen AS | Ål | 2002 |
| Ingarsteinsland Holding AS | Sperrebotn | 2005 |
| Ingasset AS | Paradis | 2005 |
| Inge Andreassen Investering AS | Hellvik | 2005 |
| Inge Blomsø AS | Bjugn | 2005 |
| Inge Fyllingsnes Holding AS | Eikangervåg | 2005 |
| Inge Krokanns Veg 14 AS | Trondheim | 2013 |
| Inge Nilsen Boligutleie AS | Myre | 2020 |
| Inge Overland AS | Brattvåg | 2022 |
| Ingeberg Utvikling AS | Furnes | 2020 |
| Ingeberglia Eiendomsutvikling AS | Hamar | 2020 |
| Ingebjørg Hansen AS | Stathelle | 2012 |
| Ingeborg Aas Vei 1 AS | Trondheim | 2017 |
| Ingeborg Aas Vei 4 Eiendom AS | Oslo | 1971 |
| Ingebret Storkaas AS | Gvarv | 1982 |
| Ingebretsen Eiendom AS | Vikersund | 1996 |
| Ingebrigt Eiendom Da | Rognan | 2005 |
| Ingebrigtsen & Sønn Eiendom AS | Narvik | 2025 |
| Ingebrigtsen Eiendom AS | Stavanger | 2024 |
| Ingebrigtsen Næringseiendom AS | Mosjøen | 2016 |
| Ingelsrud Invest AS | Hakadal | 2019 |
| Ingelsrudhagen AS | Vang På Hedmarken | 2021 |
| Ingema Holding AS | Hafrsfjord | 2015 |
| Ingenier-Proyect World Limited | Oslo | 2021 |
| Ingeniør a Hamstad AS | Flatåsen | 1968 |
| Ingeniør Arve Hågensen AS | Flatåsen | 2012 |
| Ingeniør Bjørn R Bolstad AS | Oslo | 1994 |
| Ingeniør Christen Smith & Co AS | Oslo | 2025 |
| Ingeniør Compagniet Eiendom AS | Hokksund | 2000 |
| Ingeniør L Brinchmann Mek Verksted AS | Oslo | 1961 |
| Ingeniør Og Takstmann Thomas a. Haugan AS | Drøbak | 2011 |
| Ingeniør Og Tømrermester Faye AS | Oslo | 2015 |
| Ingeniør Per Fossum AS | Oslo | 1986 |
| Ingeniør Rybergs Gate 44 AS | Oslo | 2019 |
| Ingeniør Terje Melleberg AS | Oslo | 2005 |
| Ingeniørcompagniet AS | Spikkestad | 1999 |
| Ingeniørenes Hus AS | Bergen | 1993 |
| Ingeniørenes Serviceselskap AS | Oslo | 1929 |
| Ingeniørfirma Bjørn Krutå AS | Tynset | 1983 |
| Ingeniørfirma N. Sontum AS | Bergen | 1998 |
| Ingeniørfirmaet Stensrud AS | Oslo | 1983 |
| Ingeniørgutane AS | Eidfjord | 2015 |
| Ingeniørgården AS | Levanger | 2012 |
| Ingeniørgården Bodø AS | Bodø | 2006 |
| Ingeniørhuset AS | Brumunddal | 1998 |
| Inger Aarum Werner AS | Rasta | 1992 |
| Inger Anne Ulleberg AS | Ålesund | 2000 |
| Inger Bang Lunds Vei 10-16 AS | Bergen | 1994 |
| Inger Flood Eiendom AS | Notodden | 2021 |
| Ingerfjellveien AS | Halden | 2008 |
| Ingers Hus AS | Drammen | 2025 |
| Ingert AS | Kristiansand S | 2007 |
| Ingerø Investment AS | Oslo | 2003 |
| Ingier Intrapreneur AS | Aurskog | 2008 |
| Ingierveien 6 Eiendom AS | Halden | 1997 |
| Ingkim AS | Leknes | 2021 |
| Inglis Invest AS | Tønsberg | 2005 |
| Ingo Eigendom AS | Årland | 2001 |
| Ingo Utvikling AS | Oslo | 2017 |
| Ingolf Myhre & Co Ans | Måløy | 1954 |
| Ingolf Ruuds Vei 8 AS | Oslo | 2006 |
| Ingrasso AS | Trondheim | 1999 |
| Ingridtjønna Eiendom AS | Selbu | 2017 |
| Ingulstad Feltet Nord AS | Fredrikstad | 2019 |
| Ingus AS | Oslo | 1996 |
| Inguz AS | Fornebu | 2021 |
| Ingv Ludvigsensgt 14 Ans | Drammen | 1988 |
| Ingvald Ystgaards Veg 13B AS | Trondheim | 1985 |