| Lysnes AS | Professional & scientific | 2015 |
| Lysnes Personelltjenester AS | Administrative & support | 2005 |
| Lundhs Labradoreksport A/S | Real estate | 1966 |
| Lågaveien 10 AS | Real estate | 2008 |
| Lågen Bolig AS | Real estate | 1996 |
| Låsesmeden Larvik AS | Wholesale & retail | 1998 |
| Lærerguiden Da | Professional & scientific | 2000 |
| Lærerskoleveien 35 Notodden AS | Real estate | 2010 |
| Løbergs Trafikkskole AS | Education | 2011 |
| Lødingen Holding AS | Real estate | 2017 |
| Løkka 15 AS | Real estate | 2020 |
| Løkka 17 AS | Real estate | 2014 |
| Løkka Farge AS | Wholesale & retail | 2018 |
| Løkka Tomt AS | Real estate | 2023 |
| Løveskogen Utvikling AS | Real estate | 2016 |
| Løvås Invest AS | Hospitality | 2020 |
| Løwe AS | Construction | 2015 |
| M Lund Holding AS | Real estate | 2006 |
| M&E Food AS | Wholesale & retail | 2023 |
| M.Åsbø Holding AS | | 2025 |
| M2 Eiendom AS | Real estate | 2009 |
| M2 Invest AS | Real estate | 2004 |
| Mace Investment AS | Financial services | 2014 |
| Magika AS | Real estate | 2006 |
| Magnificent Beautyspa AS | Other services | 2023 |
| Magnolic AS | Administrative & support | 2026 |
| Mahlks AS | Education | 2020 |
| Mahlt Eiendom AS | Real estate | 2006 |
| Mahlt Holding AS | Wholesale & retail | 2005 |
| Majas Bakeri AS | Manufacturing | 1993 |
| Majas Surdeigsbakeri AS | Manufacturing | 2010 |
| Maks Holding AS | Real estate | 2006 |
| Makulai AS | Wholesale & retail | 2018 |
| Malerfirma Marco Glöckner AS | Construction | 2026 |
| Malerhåndverk AS | Construction | 2026 |
| Malermester Skalleberg AS | Construction | 2012 |
| Malmøya Holding AS | | 2020 |
| Malmøya Va AS | Water & waste | 2015 |
| Malmøybrygga SA | Real estate | 1996 |
| Malot Invest AS | Construction | 2005 |
| Mama Holding AS | Financial services | 2005 |
| Managon Invest AS | Financial services | 2005 |
| Mangelrød Regnskap AS | Professional & scientific | 2023 |
| Manuelt Håndverk AS | Construction | 2018 |
| Marcussen Holding AS | | 1990 |
| Marie Gruppen AS | Information & communication | 2017 |
| Marine Montering AS | Manufacturing | 2010 |
| Marius Micula AS | Construction | 2023 |
| Marleen Holding AS | | 2023 |
| Marnic Rose AS | Real estate | 2020 |
| Martineåsen Eiendom AS | Real estate | 2014 |
| Maskin & Asfalt AS | Construction | 2008 |
| Matheo AS | Transport & logistics | 2023 |
| Mathias Olaf Nome Thorvaldsen AS | Health & social care | 2026 |
| Mathisen Hus & Hytteservice AS | Construction | 2020 |
| Mathisen Og Edvardsen Da | Arts & recreation | 1993 |
| Matss AS | | 2020 |
| Matteglød AS | Education | 2020 |
| Maya AS | Professional & scientific | 2024 |
| Mbsl Holding AS | Real estate | 2019 |
| Mcpherson Holding AS | | 2020 |
| Mcpm Europe AS | Wholesale & retail | 2020 |
| MD Zalloukh AS | Hospitality | 2026 |
| Meadows AS | Financial services | 2016 |
| Mechtech Auto AS | Other services | 2025 |
| Mechtech Caravan AS | Wholesale & retail | 2025 |
| Medcom AS | Information & communication | 2025 |
| Media Og Næringsliv AS | Professional & scientific | 2023 |
| Media Stars AS | Arts & recreation | 2020 |
| Media System AS | Wholesale & retail | 1993 |
| Media System Holding AS | Wholesale & retail | 2015 |
| Mediahuset Eiendom AS | Real estate | 1999 |
| Mediaunit AS | Information & communication | 2003 |
| Medica Curans AS | Health & social care | 2025 |
| Medicine Invest AS | Professional & scientific | 2018 |
| Mediekommunikasjon AS | Professional & scientific | 2014 |
| Megaflis Larvik AS | Wholesale & retail | 2014 |
| Meglerbyrået Ans | | 1988 |
| Meglerhuset Leinæs AS | Real estate | 1998 |
| Meierigården Eiendom AS | Real estate | 1997 |
| Meierigården Eiendom Vest AS | Real estate | 2017 |
| Mela Stein AS | Mining & quarrying | 1989 |
| Melau Pettersen AS | Professional & scientific | 2025 |
| Mellom Bøkeligate 7 AS | Real estate | 2023 |
| Mellomhagen 3 AS | Real estate | 2022 |
| Mellomholding AS | | 2026 |
| Melsomvikveien Eiendom AS | Real estate | 2015 |
| Meløstranda Ferie Og Fritid AS | Hospitality | 2016 |
| Mendo Group AS | Information & communication | 2018 |
| Merico AS | Wholesale & retail | 1998 |
| Merkantilteam AS | Professional & scientific | 1993 |
| Mesterconsult AS | Real estate | 2021 |
| Mestern Skreppestadveien 26 AS | Real estate | 2019 |
| Metall Og Skrotgutta AS | Wholesale & retail | 2025 |
| Metallco Larvik AS | Wholesale & retail | 1958 |
| Mezzala AS | Information & communication | 2026 |
| Mfo Holding AS | | 2020 |
| MHC Holding AS | | 2019 |
| Michael R Productions AS | Information & communication | 2007 |
| Microfabrikk AS | Manufacturing | 2016 |