| Kisteholmen AS | Financial services | 2005 |
| Kit and Caboodle AS | | 2019 |
| Kit AS | Wholesale & retail | 2007 |
| Kit Consult AS | Information & communication | 2024 |
| Kitagawa/Helle Produksjoner Da | Arts & recreation | 2023 |
| Kitani Bygg AS | Construction | 2025 |
| Kitchen Afrique AS | Hospitality | 2024 |
| Kitchlift AS | Professional & scientific | 2013 |
| Kite Da | Arts & recreation | 2009 |
| Kite Safari Da | Arts & recreation | 2021 |
| Kitfai Da | Information & communication | 2024 |
| Kits Beach AS | Financial services | 2016 |
| Kitsune Arkitekter AS | Professional & scientific | 2015 |
| Kitsune AS | Information & communication | 2011 |
| Kittelsen Eiendom AS | Professional & scientific | 2005 |
| Kitty AS | Wholesale & retail | 2009 |
| Kitty Og Cato Invest AS | Professional & scientific | 2005 |
| Kiva Infrastructure AS | Information & communication | 2026 |
| Kive AS | Professional & scientific | 2016 |
| Kivikoski AS | Professional & scientific | 2012 |
| Kivo AS | Information & communication | 2025 |
| Kiwa AS | Professional & scientific | 1996 |
| Kiwa Holding AS | Professional & scientific | 1987 |
| Kiwa Kompetanse AS | Professional & scientific | 2020 |
| Kiwano AS | Hospitality | 2025 |
| Kiwegians AS | Health & social care | 2025 |
| Kiwt Holding AS | | 2024 |
| Kixari AS | Professional & scientific | 2021 |
| Kizuna AS | Wholesale & retail | 2019 |
| Kiær Eiendom AS | | 2015 |
| Kiøsterudgården AS | Wholesale & retail | 2019 |
| KJ Haarr AS | | 2025 |
| KJ Prosjekt AS | Construction | 2021 |
| Kj-Data Kristensen Johansen Ans | Wholesale & retail | 1990 |
| Kjapp AS | Information & communication | 2021 |
| Kjappere Enn Kjappest AS | | 2019 |
| Kjarr AS | | 2019 |
| KJD Holding AS | | 2019 |
| Kjeckham AS | Real estate | 2005 |
| Kjedeutvikling AS | | 2022 |
| Kjegle AS | | 2026 |
| Kjehe Invest AS | | 2026 |
| Kjeiseren AS | | 2021 |
| Kjeks Holding AS | | 2020 |
| Kjeksen AS | | 2021 |
| Kjeksrud Eiendom AS | | 2026 |
| Kjeksrud Invest AS | | 2024 |
| Kjekt TV AS | Information & communication | 2022 |
| Kjeldalselva Kraft AS | Energy | 2011 |
| Kjeldgaard Assuranse AS | Financial services | 2018 |
| Kjeldsberg AS | | 2024 |
| Kjell & Company AS | Financial services | 2006 |
| Kjell a Østnes AS | Wholesale & retail | 1993 |
| Kjell B Hellum Holding AS | | 2005 |
| Kjell Høy-P AS | Professional & scientific | 2017 |
| Kjell Kristoffersen AS | Real estate | 2000 |
| Kjell Olsen Maskinforretning AS | Wholesale & retail | 2021 |
| Kjell Pop Holding AS | Real estate | 2012 |
| Kjell Svela Holding AS | | 2020 |
| Kjell Tores Mat AS | Education | 2002 |
| Kjelland, M. Nymo AS | | 2020 |
| Kjeller B3/B7 AS | Real estate | 2016 |
| Kjeller B7 Utvikling AS | Real estate | 2025 |
| Kjeller Eiendomsinvest AS | Financial services | 2021 |
| Kjeller Næringseiendom AS | Real estate | 2008 |
| Kjeller Vest 1-3 AS | Real estate | 2019 |
| Kjeller Vest 6 AS | Real estate | 2008 |
| Kjeller Vest 6 KS | Real estate | 2008 |
| Kjeller Vest 6 Newco AS | Real estate | 2026 |
| Kjeller Vest 7 AS | Real estate | 2005 |
| Kjellerholen 7 AS | Real estate | 2016 |
| Kjellerholen 9 AS | Real estate | 2016 |
| Kjellerstua Ans | Wholesale & retail | 1989 |
| Kjelleråsen Bolig AS | Real estate | 2020 |
| Kjellevold Holm Invest AS | | 2021 |
| Kjellmann Office AS | Wholesale & retail | 2024 |
| Kjells Kapell Da | Information & communication | 2014 |
| Kjellsby Holding AS | Professional & scientific | 2018 |
| Kjellsen Og Kullblikk Da | Construction | 1999 |
| Kjellstad Næringspark AS | Real estate | 2014 |
| Kjellstrand Panorama AS | Real estate | 2007 |
| Kjelsrud Eiendom AS | Real estate | 2011 |
| Kjelsrud Holding AS | Real estate | 2011 |
| Kjelstad Invest AS | | 2020 |
| Kjelsås Bilverksted AS | Other services | 2001 |
| Kjelsås Byggservice AS | Professional & scientific | 2023 |
| Kjelsås Elektro AS | Construction | 1994 |
| Kjelsås Folkets Hus SA | Real estate | 1914 |
| Kjelsås Invest AS | Real estate | 2005 |
| Kjelsås Legesenter AS | Health & social care | 2001 |
| Kjelsåsfotografen AS | Professional & scientific | 2020 |
| Kjelsåsmyra Legesenter AS | Health & social care | 2023 |
| Kjelsåsveien 130 Næring AS | Real estate | 2015 |
| Kjelsåsveien 142 AS | Real estate | 2014 |
| Kjelsåsveien 161 AS | Real estate | 2014 |
| Kjelsåsveien 170 AS | Construction | 2015 |
| Kjelsåsveien 174 AS | Real estate | 1994 |
| Kjelsåsveien 28 B AS | Households | 1950 |
| Kjelsåsveien 32 a AS | Real estate | 2012 |
| Kjelsåsveien Holding AS | Real estate | 2014 |