| Klinikk Oslo AS | Health & social care | 2009 |
| Klinikk P AS | Other services | 2022 |
| Klinikk Røa AS | Health & social care | 2013 |
| Klinikk Sagene AS | Health & social care | 2024 |
| Klinikk Toppetasjen AS | Health & social care | 2025 |
| Klinikk Vik AS | Other services | 2018 |
| Klinikk Øst AS | Health & social care | 2013 |
| Klinikk.No AS | Health & social care | 2019 |
| Klinikkdrift AS | | 2018 |
| Klink Film Da | Information & communication | 2023 |
| Klink Holding AS | | 2026 |
| Klink Kapital AS | | 2026 |
| Klink Konsulenter AS | Information & communication | 2026 |
| Klink Solutions AS | | 2025 |
| Klink Studio AS | Professional & scientific | 2025 |
| Klinkeren Holding AS | Real estate | 2019 |
| Klipp Klapp Frisør AS | Other services | 2021 |
| Klipp Klapp Holding AS | Other services | 2020 |
| Klippan AS | | 1997 |
| Klippegangen AS | Information & communication | 2014 |
| Klippekompaniet AS | Information & communication | 2012 |
| Klippelise AS | Other services | 2015 |
| Klipper Investments AS | Information & communication | 2015 |
| Klippestad Finnvest AS | | 2024 |
| KLK Invest AS | | 2023 |
| KLL Holding AS | Professional & scientific | 2012 |
| KLM Holding AS | | 2024 |
| KLM Konstruksjon AS | Construction | 2017 |
| KLM-ROYAL DUTCH AIRLINES Filial av utenlandsk foretak. NUF | Transport & logistics | 1995 |
| KLN Global Limited | Real estate | 2021 |
| Klogt AS | Information & communication | 2025 |
| Klok Forvaltning AS | | 2021 |
| Klok Regnskap AS | Professional & scientific | 2024 |
| Kloke Raad AS | Professional & scientific | 2022 |
| Klokk & Co AS | Wholesale & retail | 2016 |
| Klokk Invest AS | | 2021 |
| Klokkarlia 20 Eiendom AS | Real estate | 2021 |
| Klokkergården Omsorg AS | Real estate | 2022 |
| Klondikeband AS | Arts & recreation | 2016 |
| Kloner AS | Information & communication | 2011 |
| Klonkus AS | Information & communication | 2014 |
| Kloppen & Mann AS | Professional & scientific | 2011 |
| Klorofyll AS | Hospitality | 2017 |
| Klossen - Sio Barnehage AS | Education | 2022 |
| Klostech AS | Information & communication | 2022 |
| Kloster AS | Real estate | 2015 |
| Kloster Eiendom AS | Real estate | 2022 |
| Kloster Holding AS | Construction | 2015 |
| Kloster Invest AS | Professional & scientific | 2018 |
| Klosteret AS | Hospitality | 1998 |
| Klostergaarden AS | Professional & scientific | 1999 |
| Klostergata 30 AS | Real estate | 2012 |
| Klosterheimveien 1 AS | Real estate | 1954 |
| Klosterheimveien 1 Invest AS | Real estate | 2017 |
| Klosterkroa Hovedøya AS | Hospitality | 2023 |
| Klosterparken Ans | Real estate | 2002 |
| Kloverveien Capital AS | Wholesale & retail | 2021 |
| Klovn AS | Real estate | 2012 |
| Klovner I Kamp AS | Arts & recreation | 2012 |
| KLP Bergerveien 12 AS | Real estate | 2005 |
| KLP Biskop Gunnerusgate 14B AS | Real estate | 2006 |
| KLP Citypassagen AS | Real estate | 2015 |
| KLP Drammensveien 144 AS | Real estate | 2008 |
| KLP Eiendom AS | Real estate | 2005 |
| KLP Eiendom Holding 3 AS | Real estate | 2019 |
| KLP Eiendom Holding 4 AS | Real estate | 2019 |
| KLP Eiendom Oslo AS | Real estate | 2006 |
| KLP Eiendom Oslo Holding AS | Real estate | 2016 |
| KLP Eiendom Rom AS | Real estate | 2019 |
| KLP Eiendom Spania AS | Real estate | 2008 |
| KLP Eiendomsinvest AS | Real estate | 2005 |
| KLP Eiendomsservice AS | Real estate | 1990 |
| KLP Eufemia AS | Real estate | 2019 |
| KLP Fornebuparken AS | Real estate | 2006 |
| KLP Forsikringsservice AS | Financial services | 1993 |
| KLP Gardermoen Airport Hotel AS | Real estate | 1988 |
| KLP Hansteensgate 2 AS | Real estate | 1938 |
| KLP Huset AS | Real estate | 2006 |
| KLP Ibsenkvartalet AS | Real estate | 2005 |
| KLP Jeksleveien 10 AS | Real estate | 2020 |
| KLP Jeksleveien 100 AS | Real estate | 2018 |
| KLP Jeksleveien 120 AS | Real estate | 2018 |
| KLP Jeksleveien 36 AS | Real estate | 2022 |
| KLP Jeksleveien 47 AS | Real estate | 2025 |
| KLP Jeksleveien 50 AS | Real estate | 2021 |
| KLP Jeksleveien 51 AS | Real estate | 2025 |
| KLP Jeksleveien 55 AS | Real estate | 2025 |
| KLP Jeksleveien 59 AS | Real estate | 2025 |
| KLP Kapitalforvaltning AS | Financial services | 1993 |
| KLP Lindeberg II AS | Real estate | 2016 |
| KLP Lysaker Torg 35 Ans | Real estate | 1995 |
| KLP Lysaker Torg 45 AS | Real estate | 2005 |
| KLP Munkedamsveien 35 AS | Real estate | 2015 |
| KLP Munkedamsveien 62 AS | Real estate | 2015 |
| KLP Nordbyen AS | Real estate | 2012 |
| KLP Norfund Investments AS | Financial services | 2013 |
| KLP Næringsbygg Oslo AS | Real estate | 2006 |
| KLP Regnskapstjenester AS | Professional & scientific | 2013 |
| KLP Schweigaardsgate 17-19 AS | Real estate | 2006 |
| KLP Schweigaardsgate 21 AS | Real estate | 2007 |