| Lekeplaneten Porsgrunn AS | Wholesale & retail | 2017 |
| Lemon AS | Hospitality | 2002 |
| Lena & Jannicke Da | Arts & recreation | 2011 |
| Lenesås AS | Real estate | 2017 |
| Lerin AS | Administrative & support | 2022 |
| Lerøy Eiendom AS | Real estate | 2016 |
| Lerøy Invest AS | Construction | 2016 |
| Lerøy Vedlikehold AS | Construction | 2016 |
| Leyser Holding AS | | 2018 |
| Lgrø Holding AS | | 2023 |
| Liane 2 AS | Education | 1989 |
| Lietorvet Boligutvikling AS | Real estate | 2017 |
| Lift Consulting AS | Professional & scientific | 2026 |
| Liftgruppen AS | Wholesale & retail | 2020 |
| Liftgruppen Holding AS | Wholesale & retail | 2020 |
| Lillealpa AS | Manufacturing | 2022 |
| Lillefjaere Holding AS | | 2024 |
| Lilles Utleie AS | Administrative & support | 2023 |
| Lilly May AS | Hospitality | 2005 |
| Lilly May Med Thai AS | Hospitality | 2025 |
| Limi Boligutleie AS | Real estate | 2026 |
| Limi Utbygging AS | Real estate | 2017 |
| Lindkjenn AS | Construction | 1993 |
| Lindkjenn Eiendom AS | Real estate | 2022 |
| Lindkjenn Holding AS | Construction | 2022 |
| Lindtein AS | Professional & scientific | 2023 |
| Lindum Clairs AS | Professional & scientific | 2024 |
| Lindvall Turbo & Tuning AS | Other services | 2018 |
| Linken Holding AS | Real estate | 2005 |
| Linn Holand AS | Financial services | 2017 |
| Lino Eiendom AS | Real estate | 2005 |
| Lino Trading AS | Wholesale & retail | 1988 |
| Lintrup AS | Health & social care | 2019 |
| Livbra AS | Real estate | 2022 |
| Live Arctic AS | Professional & scientific | 2010 |
| Lk-Hk AS | | 2013 |
| LLL AS | Real estate | 2020 |
| Lotus Total AS | Administrative & support | 2020 |
| LTH1 AS | Real estate | 2016 |
| LTT Property AS | Construction | 2020 |
| Lucky Barber AS | Other services | 2021 |
| Lucky-W Holding AS | Real estate | 2022 |
| Ludmar Invest Da | | 1999 |
| Lufthelse AS | Wholesale & retail | 2021 |
| Lugano Pizzeria Ans | Hospitality | 2017 |
| Luminix AS | Wholesale & retail | 2021 |
| Lun Beauty AS | Other services | 2025 |
| Lundedalen Eiendom AS | Real estate | 2010 |
| Lundedalen Lagertjenester AS | Administrative & support | 2010 |
| Lundedalen Utvikling AS | Real estate | 2023 |
| Lundekroken 10 AS | Real estate | 2013 |
| Lundekroken Eiendom AS | Real estate | 2018 |
| Lundekroken Eiendom Da | Real estate | 2009 |
| Lunderingen 5 AS | Real estate | 2003 |
| Lune Bygg AS | Real estate | 2021 |
| Lune Eiendom AS | Real estate | 2022 |
| Lutespesialisten Ans | Manufacturing | 1989 |
| Lyskompaniet AS | Wholesale & retail | 2021 |
| Låhneveien 42 AS | Real estate | 2026 |
| Lås Og Montering AS | Other services | 2014 |
| Lærum Berg Holding AS | | 2021 |
| Løkkegt. 10-14 AS | Real estate | 2004 |
| Løndstrupp Design AS | Information & communication | 2017 |
| Lønnebakke Eiendom AS | Real estate | 2012 |
| Løpeglad AS | Information & communication | 2021 |
| Løvsjø Toppen AS | Real estate | 2016 |
| M Bolig AS | Real estate | 2022 |
| M Follaug Holding AS | | 2023 |
| M&T Transport AS | Transport & logistics | 2017 |
| M-E Holding AS | | 2024 |
| M. Johansen Holding AS | Construction | 2005 |
| M.Carlson Holding AS | Real estate | 2021 |
| M.L.Transport AS | Transport & logistics | 2018 |
| M3 Maskin AS | Construction | 2024 |
| Madsen Slip Og Service AS | Manufacturing | 2021 |
| Madsen Utleie AS | Administrative & support | 2018 |
| Madspusseropp AS | Information & communication | 2022 |
| Magne Granmar Holding AS | | 2026 |
| Magnesium Consulting AS | Professional & scientific | 2016 |
| Magnus Busk Holding AS | Real estate | 2022 |
| Mahi AS | Real estate | 2025 |
| Maja Holding AS | | 2016 |
| Malerfirma Erik Havenstrøm AS | Construction | 2011 |
| Malermester Aaltvedt AS | Construction | 2023 |
| Malisa AS | Professional & scientific | 2015 |
| Malix Eiendom AS | Real estate | 2025 |
| Malix Invest AS | Transport & logistics | 2024 |
| Malix Transport AS | Transport & logistics | 2024 |
| Malus AS | | 2019 |
| Manana AS | Real estate | 2014 |
| Marev Holding AS | Real estate | 2020 |
| Marianne Tufte Holding AS | | 2025 |
| Mariette AS | Manufacturing | 2013 |
| Markedspatruljen AS | Professional & scientific | 2024 |
| Marlon AS | | 2021 |
| Martin Fremstad AS | Health & social care | 2013 |
| Masentia AS | Wholesale & retail | 2007 |
| Maskin Holding AS | Wholesale & retail | 2021 |
| Maskinia Holding AS | Manufacturing | 2008 |
| Masosa Holding AS | Construction | 2010 |