| Katt Regnskap Og Økonomi AS | Professional & scientific | 2022 |
| KBF Invest AS | Real estate | 2021 |
| Kevo AS | Construction | 2014 |
| KH Holding AS | | 2005 |
| Kjeller Aero Senter AS | Other services | 2003 |
| Kjeller Autoservice AS | Other services | 2023 |
| Kjeller Bil AS | Real estate | 1969 |
| Kjeller Gård Drift AS | Real estate | 2015 |
| Kjeller Herrefrisør, Også for Damer Nuf | Other services | 2011 |
| Kjeller Tannhelse AS | Health & social care | 2022 |
| Kjellerholen Bilverksted AS | Other services | 2017 |
| KLB Montering AS | Construction | 2025 |
| Klubbstøtte AS | Wholesale & retail | 2024 |
| Kolb Invest AS | | 2025 |
| Kongsberg Aviation Maintenance Services AS | Manufacturing | 2016 |
| Konnect Service AS | Transport & logistics | 2024 |
| Kontek AS | Administrative & support | 2020 |
| Kontorfellesskapet ROV28 AS | Real estate | 2021 |
| Kristin Wickstrøm AS | Professional & scientific | 2025 |
| Kunpro AS | Professional & scientific | 2026 |
| Kvalitronix AS | Professional & scientific | 2014 |
| Laidback Holding AS | Wholesale & retail | 2005 |
| Laksmi Eiendom AS | Administrative & support | 2023 |
| Larissa Consulting Nuf | Administrative & support | 2013 |
| LCL Holding AS | | 2019 |
| Lead Event AS | Administrative & support | 2018 |
| Lead Gruppen AS | Administrative & support | 2019 |
| Leipziger Leuchten Nordic AS | Wholesale & retail | 2025 |
| Level-It AS | Information & communication | 2015 |
| Liban Abdi Holding AS | | 2025 |
| Liden Holding AS | | 2023 |
| Liham Medics AS | Health & social care | 2022 |
| Lillestrøm Badstue AS | Other services | 2026 |
| Lillestrøm Byggteknikk AS | Professional & scientific | 2022 |
| Lillestrøm Hudlegesenter AS | Health & social care | 2024 |
| Lillestrøm Invest AS | | 2022 |
| Lillestrøm Legesenter AS | Health & social care | 2018 |
| Lillestrøm Pizzadrift AS | Hospitality | 2025 |
| Lillestrøm Storhusholdning AS | Wholesale & retail | 2018 |
| Lsk-Hallen AS | Arts & recreation | 2002 |
| Lukas Betong AS | Construction | 2019 |
| Lukas Drift Og Utleie AS | Real estate | 2024 |
| Lysgård & Steensnæs Eiendom AS | Real estate | 2019 |
| Løkenåsen Boligutvikling AS | Construction | 2019 |
| Lørenskog Autosenter AS | Administrative & support | 2002 |
| M.S. Holding AS | | 2019 |
| M40 Eiendom AS | Real estate | 1976 |
| Madame S AS | Other services | 2024 |
| Make Estate AS | | 2022 |
| Makeover Bolig AS | Construction | 2026 |
| Makeover Property AS | Real estate | 2022 |
| Malermester Ragnar Torp AS | Construction | 1984 |
| Malta Holding AS | Real estate | 2019 |
| Maroma Eiendom AS | Real estate | 1990 |
| Maximize Living AS | Professional & scientific | 2025 |
| Mbtr Holding AS | | 2023 |
| MCJ Holding AS | | 2024 |
| MDH Holding AS | | 2020 |
| Meadow Holding AS | | 2020 |
| Meglerhuset Romerike AS | Real estate | 2025 |
| Mek Holding AS | | 2019 |
| Melk Invest AS | Professional & scientific | 2006 |
| Mest AS | | 2022 |
| Mileo Invest AS | Professional & scientific | 2019 |
| Mitt Dekkhotell Lillestrøm AS | Transport & logistics | 2022 |
| Mo Auto AS | Wholesale & retail | 2024 |
| Moamo AS | Financial services | 2014 |
| Mobile Kjeller AS | Wholesale & retail | 2011 |
| Moki Norge AS | Transport & logistics | 2012 |
| Molander Entreprenør AS | Real estate | 2025 |
| Molar AS | Health & social care | 1989 |
| Moore & Sons AS | Professional & scientific | 2016 |
| Motor Forum AS | Wholesale & retail | 1985 |
| Mozmo Invest AS | | 2020 |
| MP Tech AS | | 2025 |
| Muri Holding AS | Real estate | 2005 |
| Mza Invest AS | Health & social care | 2014 |
| Nael Holding AS | Health & social care | 2022 |
| Nakken Holding AS | | 2024 |
| NB Transport & Service AS | Transport & logistics | 2021 |
| Nellemann Machinery AS | Wholesale & retail | 1991 |
| Newtalent AS | Professional & scientific | 2019 |
| Nexrør AS | Construction | 2024 |
| Niit Holding AS | Professional & scientific | 2024 |
| Noe Fishy AS | Wholesale & retail | 2025 |
| Nor-Alb Eiendom AS | | 2009 |
| Norab AS | Wholesale & retail | 2019 |
| Nordic Kapital AS | | 2025 |
| Nordic One AS | Transport & logistics | 2022 |
| Nordic Season Products AS | Wholesale & retail | 2005 |
| Norfax AS | Wholesale & retail | 1995 |
| Norsar Innovation AS | Information & communication | 2005 |
| Norsk Naturstein AS | Manufacturing | 2001 |
| Norsk Turnetransport AS | Transport & logistics | 1990 |
| Norway Offshore Racing Team AS | Professional & scientific | 2020 |
| Nova Nordics AS | Wholesale & retail | 2026 |
| Novus Systems AS | Administrative & support | 2020 |
| Nstar AS | Professional & scientific | 2012 |
| Numan Holding Limited AS | Construction | 2022 |
| NVV2-4 AS | Real estate | 2025 |