| Mademoiselle Oy | Wholesale & retail | 2021 |
| Magenta Racing Oy | Arts & recreation | 2014 |
| Mainosteam Ky Apiainen | Professional & scientific | 1990 |
| MaisoNetti Oy | Wholesale & retail | 2017 |
| Majalahti consulting Oy | Other services | 2023 |
| Majava Group Oy | Manufacturing | 2008 |
| Majory Ky | Construction | 2013 |
| Makader Ky | Construction | 2007 |
| Malvanojan Lämpö Oy | Energy | 1977 |
| Maqqe Services Oy | Education | 2021 |
| Marketeo Oy | Professional & scientific | 2025 |
| Martti Montonen Oy | Financial services | 1989 |
| Mat-Sit Oy | Financial services | 2022 |
| Matima Oy | Health & social care | 1990 |
| MatkaPaletti Oy | Administrative & support | 2004 |
| Matroskin Oy | Professional & scientific | 2016 |
| Mattili Oy | Professional & scientific | 2023 |
| Mauton Talli Oy | Wholesale & retail | 2017 |
| Mavu-Rakenne Ky | Construction | 1999 |
| Me Tuomelat oy | Administrative & support | 2017 |
| Medi-Uosso Oy | Real estate | 2025 |
| Mediatoimisto Dorimedia Oy | Professional & scientific | 2010 |
| Mehumäki Oy | Professional & scientific | 1980 |
| Meidänboksi Oy | Arts & recreation | 2019 |
| Merika Oy | Health & social care | 2005 |
| Merikarvian Meriranta Oy | Real estate | 1996 |
| MetSävi Oy | Agriculture & fishing | 2020 |
| Metallikoneistamo VMS Oy | Manufacturing | 1987 |
| Metallinkeräys Romutiimi Oy | Water & waste | 2019 |
| Metallipalvelu Koskinen Oy | Manufacturing | 2012 |
| Metle Oy | Manufacturing | 2022 |
| Metsäkoneurakointi Rauva & Rauva Oy | Agriculture & fishing | 1995 |
| Metsäkoneurakointi Tapani Männistö Ky | Agriculture & fishing | 1988 |
| Metsäkuljetus Kranni Oy | Agriculture & fishing | 1987 |
| Metsärahti Mikkola Oy | Transport & logistics | 2019 |
| Metsätilat.fi Palvelut Oy | Administrative & support | 2020 |
| Mettäperä Oy | Construction | 2005 |
| Metwell Oy | Manufacturing | 2016 |
| Micmedi Oy | Wholesale & retail | 2007 |
| Miekkaojan Murske Ky | Mining & quarrying | 1994 |
| Miina-N Oy | Hospitality | 2020 |
| Mika Myllymaa Oy | Wholesale & retail | 1992 |
| Mikä O Oy | Real estate | 2020 |
| Minding My Own Business Oy | Arts & recreation | 2011 |
| Minttumanteli om. Sointu ja Timo Mikael Kiikala | Wholesale & retail | 1981 |
| Mirak Oy | Hospitality | 2005 |
| Missä kuitti Oy | Transport & logistics | 2023 |
| Monomeeri Oy | Manufacturing | 2004 |
| Mosquito Biker Oy | Wholesale & retail | 2000 |
| Motivox Terapiapalvelut avoin yhtiö | Health & social care | 2003 |
| Motofin Oy | Health & social care | 2019 |
| Mouhi Invest Oy | Professional & scientific | 2023 |
| Mouhijärven Asunnot Oy | Real estate | 1999 |
| Mouhijärven Betoni Oy | Manufacturing | 1985 |
| Mouhijärven Hoitokoti Vanha-Pappila Oy | Health & social care | 2000 |
| Mouhijärven KJ-Halli Oy | Real estate | 1989 |
| Mouhijärven Kiinteistönhoito Oy | Administrative & support | 2018 |
| Mouhijärven Koneasema Oy | Agriculture & fishing | 2019 |
| Mouhijärven Kukkasidonta ja Lahja Oy | Wholesale & retail | 2004 |
| Mouhijärven Kumikorjaamo Ky | Wholesale & retail | 1980 |
| Mouhijärven Osuuspankki | Financial services | 1923 |
| Mouhijärven Sijoitus Oy | Professional & scientific | 1987 |
| Mouhijärven Tili ja Isännöinti Oy | Professional & scientific | 1984 |
| Multiparts Oy | Wholesale & retail | 2020 |
| Murtoo Oy | Real estate | 2026 |
| Musatilit Oy | Administrative & support | 2015 |
| Mustajärven alueen vesihuolto-osuuskunta | Water & waste | 2007 |
| Mutsis Oy | Administrative & support | 2017 |
| Myllypuu, Avoin yhtiö | Wholesale & retail | 1981 |
| Mymmeliini Oy | Health & social care | 2025 |
| Myyntivoima Partnerit Oy | Administrative & support | 2002 |
| Mäki Design Oy | Construction | 2001 |
| Mäki-Soinin Kauppahuone Oy | Professional & scientific | 2026 |
| Mäntyniemen Puu Oy | Manufacturing | 2013 |
| NH-Koneistus Oy | Manufacturing | 1986 |
| NI-PE Oy | Transport & logistics | 2002 |
| NK Forest OY | Agriculture & fishing | 2021 |
| NK-Yhtymä Oy | Wholesale & retail | 2003 |
| NL Kone ja Metalli Oy | Construction | 2022 |
| Nummihirsi Ky | Construction | 2000 |
| Nahkatuote Donna Avoin Yhtiö | Manufacturing | 1996 |
| Naku Naturals Oy | Manufacturing | 2025 |
| Nandel Ventures Oy Ab | Financial services | 2008 |
| Narte Oy | Real estate | 2009 |
| Nasko oy | Other services | 2026 |
| Naval Valves Oy | Manufacturing | 2017 |
| Netland Oy | Information & communication | 1996 |
| Nevidera Oy | Information & communication | 2026 |
| Niemen Kiinteistöt Oy | Real estate | 1989 |
| Niemen Talkkuna Ky | Manufacturing | 1983 |
| Niemen Tehtaat Finland Oy | Manufacturing | 2023 |
| Niemen Tehtaat Oy | Manufacturing | 1945 |
| Niemi Steel Oy | Manufacturing | 1965 |
| Niilex Oy | Real estate | 2001 |
| Niirasuomi Ky | Manufacturing | 1987 |
| Niittymäki Yhtiöt Oy | Construction | 2000 |
| Nira Pumps Oy | Manufacturing | 2013 |
| Niura Oy | Agriculture & fishing | 2020 |
| No Fake Oy | Information & communication | 2024 |
| Nokian Kauppahuone Hanna Marja Ky | Wholesale & retail | 2004 |