| Kongsberg Tynnplate AS | Manufacturing | 2004 |
| Konnerudgata 73 AS | Real estate | 2025 |
| Kopstad Og Haugen Eiendom AS | Real estate | 2014 |
| Kornelia Hydro-Servis AS | Construction | 2021 |
| Kortkiosken AS | | 2026 |
| Kowalczyk Snekkerservice AS | Construction | 2023 |
| KR Larsen Maskinentreprenør AS | Construction | 2003 |
| Kraften Store AS | Wholesale & retail | 2023 |
| Kreative Perspektives AS | Professional & scientific | 2019 |
| Krekling AS | | 2005 |
| Kressen Holding AS | Real estate | 2021 |
| Krislo Holding AS | Financial services | 2015 |
| Kristma AS | Real estate | 2017 |
| Kristoffersen AS | Construction | 2016 |
| KST 1 Holding AS | Professional & scientific | 2024 |
| KST Logistikk AS | Transport & logistics | 2024 |
| KST Materiell AS | Administrative & support | 2024 |
| Kunnskapsparken Eiker AS | Real estate | 2007 |
| Kåre & Svein Rønningen AS | Construction | 1995 |
| Lady & Landstrykeren Barneklær AS | Wholesale & retail | 2010 |
| Lahelleveien 5 Eiendom AS | Real estate | 2014 |
| Landsbylege Stine AS | Health & social care | 2024 |
| Landskapsentreprenørene Øst AS | Administrative & support | 2026 |
| Langebru Gjestegård AS | Hospitality | 1993 |
| Langerud AS | Real estate | 2021 |
| Langerud Eiendom Da | Real estate | 2002 |
| Lapatio AS | Wholesale & retail | 2018 |
| Larsen Og Nilsen Eiendom AS | Real estate | 2013 |
| Lauvtjernveien 4 AS | Real estate | 2021 |
| Legehuset AS | Health & social care | 2001 |
| Leif Roar Og Jarle Johansen Da | Real estate | 2011 |
| Leonberg AS | Financial services | 2015 |
| Lerberg Eiendom AS | Real estate | 1997 |
| Letmolie Invest AS | Financial services | 2014 |
| Liaåsen Holding AS | Construction | 2012 |
| Libera Invest AS | Real estate | 2007 |
| Lie & Solum Graveservice Ans | Construction | 1989 |
| Liegården AS | Real estate | 2016 |
| Lilleås Holding AS | | 2019 |
| Limano AS | Financial services | 2015 |
| Lire Holding AS | | 2024 |
| LMC Holdings AS | Professional & scientific | 2018 |
| Lny AS | | 2022 |
| Loe Bruk 13 AS | Real estate | 2015 |
| Loe Bruk 14 AS | Construction | 1987 |
| Loe Bruk AS | Real estate | 2010 |
| Loe Bruk Tomt 1 AS | Real estate | 2014 |
| Loe Elementmontasje AS | Construction | 2011 |
| Loe Rørprodukter AS | Manufacturing | 1997 |
| Loesmoen Eiendom AS | Real estate | 2006 |
| Loselva AS | Energy | 2010 |
| Lumina Helse AS | Health & social care | 2022 |
| Lumtech AS | Professional & scientific | 2025 |
| Lundheim Invest AS | | 2024 |
| Luza AS | Real estate | 2016 |
| Lykkespill AS | Arts & recreation | 2015 |
| Lysaker Byggprosjekt Og Bad A/S | Construction | 2022 |
| Lø Invest AS | Financial services | 2007 |
| M E Consulting AS | Real estate | 2019 |
| M. Pedersen Kuldeteknikk AS | Construction | 2016 |
| Mabels AS | Wholesale & retail | 2010 |
| Mad River AS | Wholesale & retail | 2022 |
| Magne Og Jan Berget Anleggsdrift AS | Construction | 1983 |
| Maheni AS | | 2017 |
| Maheto AS | Real estate | 2013 |
| Manometeren AS | Real estate | 2015 |
| Marianne AS | Wholesale & retail | 1970 |
| Markalabben AS | Administrative & support | 2023 |
| Marry Juliet AS | Wholesale & retail | 2018 |
| Marryjuliet Da | Wholesale & retail | 2018 |
| Maskin & Veidrift AS | Construction | 2022 |
| Matbua AS | Wholesale & retail | 1991 |
| Mays Fotklinikk AS | Health & social care | 2021 |
| MBB Holding AS | | 2021 |
| MCH Graving AS | Construction | 2022 |
| Metin AS | | 2024 |
| Midtun Prosjekt AS | Professional & scientific | 2000 |
| Milele AS | Information & communication | 2026 |
| Mili AS | Real estate | 2018 |
| Millefiori AS | Wholesale & retail | 2016 |
| Miras LT Nuf | Professional & scientific | 2015 |
| Mirawa House AS | Hospitality | 2016 |
| MKS1 AS | | 2022 |
| MKS2 AS | | 2022 |
| MKS3 AS | | 2022 |
| Mobcast AS | Information & communication | 2000 |
| Mobile Eiendom AS | Real estate | 2004 |
| Mobile Hokksund AS | Wholesale & retail | 2007 |
| Mobile Invest AS | Wholesale & retail | 2025 |
| Mobilegroup AS | Wholesale & retail | 2005 |
| Mobilezentrum AS | Wholesale & retail | 2010 |
| Mobilezervice AS | Other services | 2007 |
| Modul Master AS | Professional & scientific | 2021 |
| Modulent AS | Real estate | 2018 |
| Morad AS | Transport & logistics | 2020 |
| Morten Borgan AS | | 1998 |
| Morten Lie Holding AS | | 2013 |
| MR D Invest AS | | 2023 |
| MS Market AS | Wholesale & retail | 2026 |
| MSB Entreprenør AS | Professional & scientific | 2012 |