| Mini Kart Service Ky | Wholesale & retail | 1989 |
| Mini-Bar Pisa Ky | Wholesale & retail | 1994 |
| Miras Pizza Group Oy | Hospitality | 2021 |
| Mitara Oy | Other services | 2013 |
| Mitrade Oy | Professional & scientific | 1988 |
| Mixuri Oy | Manufacturing | 2013 |
| Moision Nostovoima Oy | Construction | 2006 |
| Moments Industry Oy | Information & communication | 2024 |
| Monday Road Oy | Professional & scientific | 2022 |
| Monitoimirengas Oy | Wholesale & retail | 2006 |
| Movemeko Oy | Other services | 2019 |
| MunjaSun Oy | Financial services | 2024 |
| Muovihaka Oy | Manufacturing | 1989 |
| My Luck Oy | Real estate | 2023 |
| Myyntialho Oy | Health & social care | 1980 |
| Mäkinen & Harju avoin yhtiö | Wholesale & retail | 2015 |
| N.O. Service Oy | Construction | 2011 |
| NFLogistics Oy | Transport & logistics | 2021 |
| NH-Koneet Oy | Wholesale & retail | 2007 |
| NSP-Sähköpalvelu Oy | Construction | 1993 |
| NV Nostot ja Palvelut Oy | Construction | 2021 |
| Nalleva Oy | Real estate | 2025 |
| Neea Music Oy | Professional & scientific | 2013 |
| Nerphy Oy | Health & social care | 2023 |
| Nestructive Entertainment Oy | Arts & recreation | 2021 |
| Nevacom Oy | Wholesale & retail | 2005 |
| NiNi Invest Oy | Real estate | 2025 |
| NicLa Oy | Wholesale & retail | 2015 |
| Nicekauppias Oy | Wholesale & retail | 2022 |
| Niiniteam Oy | Real estate | 1991 |
| Niksa Invest Oy | Professional & scientific | 2024 |
| Nipanapauttaja Oy | Financial services | 2024 |
| Noise House Oy | Professional & scientific | 1998 |
| NordVista Rakennus Oy | Construction | 2026 |
| Nordqvist Oy | Wholesale & retail | 1987 |
| Nordstock Ltd. Oy | Wholesale & retail | 2025 |
| Norsa Oy | Manufacturing | 2013 |
| North69 Ky | Education | 2018 |
| Northern Light Training Oy | Information & communication | 2026 |
| Nosturi ässä Oy | Professional & scientific | 2021 |
| Nova Innovations Oy | Information & communication | 2007 |
| Nugen Halli Oy | Real estate | 1992 |
| Nurcon Oy | Construction | 2022 |
| Nurmijärven Automyynti Oy | Wholesale & retail | 2019 |
| Nurmijärven Betoni Oy | Manufacturing | 1989 |
| Nurmijärven Fysioterapia Oy | Health & social care | 1995 |
| Nurmijärven Hammaslääkäriasema Oy | Health & social care | 2005 |
| Nurmijärven Kivi Oy | Real estate | 1991 |
| Nurmijärven Kodit Oy | Real estate | 1989 |
| Nurmijärven Kotiapu Oy | Health & social care | 1998 |
| Nurmijärven Laatuauto Oy | Wholesale & retail | 2006 |
| Nurmijärven Lasitalo Oy | Construction | 1981 |
| Nurmijärven Linja Oy | Transport & logistics | 1935 |
| Nurmijärven Metsäpuisto Oy | Real estate | 1983 |
| Nurmijärven Momex Oy | Professional & scientific | 1998 |
| Nurmijärven Mosaiikkituote Oy | Manufacturing | 1992 |
| Nurmijärven PK-Tilipalvelu Oy | Professional & scientific | 1989 |
| Nurmijärven Peltityö Koskinen Oy | Manufacturing | 1974 |
| Nurmijärven Puutekniikka Ky | Construction | 2001 |
| Nurmijärven Rakennushuolto Oy | Administrative & support | 1991 |
| Nurmijärven Rauta L. Käyhkö Ky | Wholesale & retail | 1990 |
| Nurmijärven Sähkö Oy | Energy | 1993 |
| Nurmijärven Sähköautohuolto Oy | Other services | 2024 |
| Nurmijärven Sähköverkko Oy | Energy | 2010 |
| Nurmijärven Teräskone Oy | Manufacturing | 2005 |
| Nurmijärven Timanttiporaus Oy | Construction | 2003 |
| Nurmijärven Vienti Oy | Administrative & support | 2020 |
| Nurmijärven Värisuora Oy | Financial services | 2001 |
| Nurmijärven laatukuljetus Oy | Transport & logistics | 2023 |
| Nurmitapetti Oy | Wholesale & retail | 1976 |
| Nuvotek Oy | Construction | 2026 |
| OBO Bettermann Oy | Wholesale & retail | 2000 |
| OLOWOYO LOGISTICS avoin yhtiö | Transport & logistics | 2020 |
| OT-Louhinta Oy | Construction | 2023 |
| Ollonqvistin Näyttämötekniikka Oy | Arts & recreation | 1994 |
| Omarakentaja Oy | Construction | 2020 |
| Omaremix Oy | Real estate | 2020 |
| Onganranta Oy | Information & communication | 2014 |
| Onni Food Oy | Manufacturing | 2024 |
| Onni Pro Oy | Construction | 2016 |
| Optima Finland Oy | Administrative & support | 2004 |
| Optivest Oy | Financial services | 2024 |
| Oridos Oy | Construction | 1998 |
| OsumaTech Oy | Information & communication | 2025 |
| Osuuskunta Eco-One | Professional & scientific | 1995 |
| Osuuskunta Puuvitonen | Arts & recreation | 1990 |
| Outi Gyldén Communications Oy | Information & communication | 2023 |
| Oy Arco Transport Ab | Transport & logistics | 2014 |
| Oy Cronimo Ab | Wholesale & retail | 1981 |
| Oy Digi Sewer Productions Ltd | Professional & scientific | 2003 |
| Oy Ecu-Kapital Ab | Professional & scientific | 1993 |
| Oy Ferox Tube Ab | Wholesale & retail | 2000 |
| Oy NK Yhtiöt Ab | Construction | 1989 |
| Oy Viherprojektit - Greenprojects Ab | Administrative & support | 1979 |
| Oy Vip-Oil Ltd. | Real estate | 1997 |
| PD Group Oy | Education | 2023 |
| PJL Consulting Oy | Professional & scientific | 2019 |
| PLC Sales Ky | Wholesale & retail | 2024 |
| PMK-Kaivuu Oy | Construction | 2008 |
| PS-Rakenne Pasi Sutelainen Oy | Construction | 2006 |