| Kollektivet Ans | Professional & scientific | 2023 |
| Kollektivtrafikkens Personellservice SA | Other services | 1995 |
| Kollensvevet AS | Arts & recreation | 2015 |
| Kollerøs Holding AS | | 2024 |
| Kollingen AS | Real estate | 1990 |
| Kolltveit AS | Real estate | 2023 |
| Kollvest AS | | 2021 |
| Kolofon Forlag AS | Information & communication | 2005 |
| Kolon Arkitektur AS | Professional & scientific | 2018 |
| Kolonihagen AS | Wholesale & retail | 2012 |
| Kolonihagen Bakeri AS | Manufacturing | 2009 |
| Kolonihagen Frogner AS | Hospitality | 2009 |
| Kolonihaven Studio AS | Professional & scientific | 1994 |
| Kolor Da | Wholesale & retail | 2006 |
| Kolours Jewelry AS | Wholesale & retail | 2015 |
| Kolrud Eiendom AS | Real estate | 2021 |
| Kols Capital AS | Real estate | 2018 |
| Kolsaker AS | | 2021 |
| Kolset Holding AS | | 2021 |
| Kolseth Invest Holding AS | Real estate | 2024 |
| Kolskogheiane Næringspark AS | Real estate | 2015 |
| Kolsrud AS | Households | 1955 |
| Kolsrud Group AS | Transport & logistics | 2016 |
| Kolsrud Invest AS | Real estate | 2014 |
| Kolsrud Living AS | | 2022 |
| Kolsrud Services AS | Transport & logistics | 2017 |
| Kolstad Erdal Holding AS | | 2026 |
| Kolstadgata 1 Eiendom AS | Real estate | 2007 |
| Kolstadgata 20 AS | Real estate | 2015 |
| Kolstadgata 20 Holding AS | | 2026 |
| Kolstadgaten 18 AS | Wholesale & retail | 2010 |
| Kolsås Holding AS | | 2022 |
| Kolsåstoppen AS | Financial services | 2005 |
| Kolsåstoppen Invest AS | Real estate | 2005 |
| Kolsø Invest AS | Construction | 2024 |
| Koltorpneset Vann Og Avløp SA | Water & waste | 2006 |
| Koluder AS | | 2023 |
| Kolvani AS | | 2025 |
| Kolvereid Eiendom AS | Real estate | 2007 |
| Kolås AS | | 2019 |
| Kolåsbakken Barnehage SA | Education | 1998 |
| Kom Invest AS | Real estate | 2004 |
| KOM24 AS | Administrative & support | 2021 |
| Komane AS | Information & communication | 2013 |
| Kombi Oslo AS | Real estate | 2025 |
| Kombibygg AS | Real estate | 2016 |
| Kombieiendom Østlandet AS | Real estate | 2014 |
| Koment Explorer AS | Administrative & support | 1998 |
| Komet Film AS | Information & communication | 2013 |
| Komfort Design AS | Construction | 2016 |
| Komijn AS | | 2018 |
| Komissar AS | Professional & scientific | 2025 |
| Komite AS | Other services | 2010 |
| Komma Frisør AS | Other services | 1989 |
| Komma.No AS | Information & communication | 2013 |
| Kommando AS | Information & communication | 2017 |
| Kommando Holding AS | Information & communication | 2017 |
| Kommerst Rådgivning AS | Professional & scientific | 2026 |
| Kommfrem AS | Professional & scientific | 2014 |
| Kommunal Landspensjonskasse Gjensidig Forsikringsselskap | Financial services | 1949 |
| Kommunalbanken AS | Financial services | 1999 |
| Kommunekompetanse AS | Professional & scientific | 2008 |
| Kommunekonsult AS | Professional & scientific | 2002 |
| Kommunekraft AS | Energy | 1993 |
| Kommunenes Hus AS | Real estate | 1983 |
| Kommuneoverlegene AS | Health & social care | 2025 |
| Kommunika AS | Professional & scientific | 2025 |
| Kommunikasjon AS | Professional & scientific | 2023 |
| Kommunikasjonshuset Holding AS | Real estate | 2001 |
| Kommunikasjonshuset Involve! AS | Professional & scientific | 2022 |
| Komnorge AS | Education | 2021 |
| Komodo AS | Real estate | 2020 |
| Komodo Holding AS | Real estate | 2020 |
| Komodo Kommunikasjon Da | Professional & scientific | 2010 |
| Komon AS | Administrative & support | 1996 |
| Komon Eiendom Og Invest AS | Administrative & support | 2005 |
| Komon Publishing AS | Information & communication | 2017 |
| Komorebi Arkitekter AS | Professional & scientific | 2025 |
| Kompa AS | Professional & scientific | 2017 |
| Kompaktbygg AS | Wholesale & retail | 2000 |
| Kompan AS | Information & communication | 2014 |
| Kompani Baluba SA | Arts & recreation | 2024 |
| Kompani Kaktus Da | Arts & recreation | 2009 |
| Kompani Mellom Ans | Arts & recreation | 2025 |
| Kompani Venus Ans | Arts & recreation | 2023 |
| Kompanito - Da | Arts & recreation | 2015 |
| Kompanjongene AS | Professional & scientific | 2016 |
| Kompany AS | Information & communication | 2023 |
| Kompass Havvind AS | Energy | 2020 |
| Kompass Karriere AS | Education | 2018 |
| Kompass Norge AS | Information & communication | 1969 |
| Kompass Oslo AS | Real estate | 2012 |
| Kompasskurs AS | Education | 2018 |
| Kompat Consult AS | Information & communication | 2013 |
| Kompatibel AS | Professional & scientific | 2005 |
| Kompetanse Gruppen AS | Education | 2020 |
| Kompetansebanken AS | Administrative & support | 2007 |
| Kompetansebedriften AS | Education | 2015 |
| Kompetansehuset Neo AS | Education | 2016 |
| Kompetansetorget AS | Professional & scientific | 2009 |