| Leirvika Vannverk SA | Water & waste | 2018 |
| Lensmann Havigs Gate Eiendom AS | Real estate | 1999 |
| LG Verge AS | Other services | 2024 |
| LHH Invest AS | Real estate | 2018 |
| Liljefjell Holding AS | | 2022 |
| Line Berre Fotografi AS | Professional & scientific | 2023 |
| Line Borkmo Holding AS | | 2025 |
| LL Utleie AS | Real estate | 2022 |
| Logene I Namsos AS | Real estate | 2006 |
| LOGOPED1 AS | Health & social care | 2021 |
| Longbeach Holding AS | Financial services | 2018 |
| Lunula Velvære Og Interiør AS | Other services | 2012 |
| Lås & Beslagsservice AS | Construction | 2026 |
| Lås & Sikring AS | Construction | 2005 |
| Løvegen 5 AS | Real estate | 2023 |
| Løvegen 8 AS | Real estate | 2021 |
| Løvmo Eiendom Da | Real estate | 1999 |
| Løvsjølia Vestre Hyttevel SA | Other services | 2018 |
| M Aakervik AS | Manufacturing | 1948 |
| M Glømmen Holding AS | | 2024 |
| Ma.Jo Holding AS | | 2024 |
| Madmar Invest AS | | 2025 |
| Magnus Wester AS | Other services | 2012 |
| Malermester Jan Husby AS | Construction | 2014 |
| Mana Sykkel AS | Wholesale & retail | 1997 |
| Maras AS | Transport & logistics | 2012 |
| Mariel Eiendom AS | Real estate | 2023 |
| Marine Seajoy Da | Education | 2025 |
| Marius Aakervik Invest AS | | 2022 |
| Marøyvollen AS | Real estate | 2023 |
| Matanina AS | Other services | 2025 |
| Matkompaniet AS | Wholesale & retail | 2005 |
| Matra AS | Administrative & support | 2017 |
| Medvind Invest Namsos AS | Education | 2016 |
| Megasun Namsos AS | Other services | 2017 |
| Mel's Kitchen & Catering AS | Hospitality | 2020 |
| Merlin Kids Namsos AS | Wholesale & retail | 2005 |
| Mester Bygg AS | Construction | 2016 |
| Metro Frisører AS | Other services | 2003 |
| Midt-Norsk Biovarme AS | Energy | 2021 |
| Midt-Norsk Massivtre AS | Wholesale & retail | 2019 |
| Midtec AS | Construction | 2021 |
| Midtnorsk Eiendom AS | Real estate | 1995 |
| Midvest I AS | Financial services | 2007 |
| Miljø AS | Other services | 2008 |
| Minitjenester AS | Professional & scientific | 2023 |
| Mint Hårstudio AS | Other services | 2022 |
| Mno Invest AS | | 2020 |
| Moe-Invest AS | Real estate | 2020 |
| Moelven Van Severen AS | Manufacturing | 2000 |
| Mohes AS | | 2021 |
| Monjabekkavik AS | Wholesale & retail | 2024 |
| Mossgrowth AS | Professional & scientific | 2024 |
| Mote Invest AS | Wholesale & retail | 2011 |
| Motestrikk AS | Wholesale & retail | 2015 |
| Motor Labs AS | Information & communication | 2021 |
| Movi Invest AS | Financial services | 2007 |
| MP Aar Invest AS | | 2026 |
| Multiservice-Namsos Da | Administrative & support | 2007 |
| Murmester Zielinski AS | Administrative & support | 2024 |
| Mystory Norge AS | Professional & scientific | 2019 |
| Mørk Utleie AS | Real estate | 2021 |
| N Jørgensen Invest AS | Real estate | 1990 |
| Namdal Bil Og Transport AS | Transport & logistics | 2022 |
| Namdal Bilskade AS | Other services | 2006 |
| Namdal Bolig Og Takst AS | Real estate | 1998 |
| Namdal Bygg AS | Construction | 2026 |
| Namdal Catering AS | Hospitality | 2017 |
| Namdal Dyrehelse AS | Agriculture & fishing | 2022 |
| Namdal Eiendom AS | Real estate | 2007 |
| Namdal Fotterapiklinikk AS | Health & social care | 2021 |
| Namdal Glasservice AS | Construction | 1986 |
| Namdal Investor AS | Financial services | 2005 |
| Namdal Multiservice AS | Wholesale & retail | 2021 |
| Namdal Mur Og Flis AS | Construction | 2025 |
| Namdal Ressurs AS | Wholesale & retail | 1991 |
| Namdal Ressurs Holding AS | | 2025 |
| Namdal Snekkerlag AS | Construction | 1994 |
| Namdal Takst Og Byggtjenester AS | Professional & scientific | 2018 |
| Namdal Transport AS | Transport & logistics | 2011 |
| Namdal Transport Drift AS | Transport & logistics | 2025 |
| Namdal Utleie AS | Wholesale & retail | 2018 |
| Namdal Utvikling AS | Professional & scientific | 2026 |
| Namdalgruppen AS | Construction | 2020 |
| Namdalsavisa AS | Information & communication | 1990 |
| Namdalsvegen 80 AS | Real estate | 2026 |
| Namoplastbygget AS | Real estate | 2007 |
| Namsen Eiendomsutvikling AS | Real estate | 2022 |
| Namsen Fjellservice AS | Construction | 2020 |
| Namsen Fjordferie AS | Real estate | 1982 |
| Namsen Holding AS | | 2020 |
| Namsos Audio Senter AS | Manufacturing | 1995 |
| Namsos Bandasje AS | Wholesale & retail | 2003 |
| Namsos Bar Eiendom AS | Real estate | 2017 |
| Namsos Bardrift AS | Hospitality | 2026 |
| Namsos Begravelsesbyrå AS | Other services | 2023 |
| Namsos Bil Og MC Trafikkskole AS | Education | 2010 |
| Namsos Bilberging AS | Transport & logistics | 2023 |
| Namsos Bilteknikk AS | Other services | 2023 |
| Namsos Blomsterhandel AS | Wholesale & retail | 1977 |