| MTO Industries Oy | Construction | 2017 |
| MTO-Sähkö Oy | Professional & scientific | 2006 |
| MVP Laatusaneeraus Oy | Construction | 2009 |
| MVP Metalli Oy | Manufacturing | 2026 |
| Maalaus & Sisustus Pekka Martimo Oy | Construction | 1998 |
| Maalaus Syri avoin yhtiö | Construction | 2014 |
| Maalausliike Kalliosalmi Oy | Construction | 2015 |
| Maanrakennus Alamäki Oy | Administrative & support | 1993 |
| Maanrakennus Ari Tapo Oy | Administrative & support | 2000 |
| Maanrakennus J. Pränni Oy | Construction | 2021 |
| Maanrakennus J.Koskela Oy | Real estate | 2018 |
| Maanrakennus Kari ja Tommi Pietikäinen Ay | Construction | 2005 |
| Maanrakennus Kinnunen Oy | Construction | 2025 |
| Maanrakennus Kvist Oy | Construction | 1991 |
| Maanrakennusliike Tuomo Lahdenperä ky | Construction | 1990 |
| Maansiirto Mykkälä Oy | Construction | 2015 |
| Maansiirtoliike Kyösti Kaihu Oy | Construction | 1991 |
| Maarakennus Veljekset Lehto Oy | Construction | 1999 |
| Maatalousurakointipalvelut Raimo Koli Ky | Transport & logistics | 2010 |
| Mainos & Kuva Hyvärinen Oy | Professional & scientific | 2022 |
| Mainostoimisto Crea Oy | Professional & scientific | 2009 |
| MaitoSten Oy | Agriculture & fishing | 2019 |
| Majedy Invest Oy | Administrative & support | 2023 |
| MakeCHL Oy | Wholesale & retail | 2020 |
| Malatya Avoin Yhtiö | Hospitality | 2012 |
| Malla Marketing Oy | Financial services | 2020 |
| Manga LNG Oy | Mining & quarrying | 2014 |
| Manga Terminal Oy | Wholesale & retail | 2014 |
| Marin Pirtti Ky | | 1989 |
| Maritiina Oy | Construction | 1989 |
| Markkinointipalvelu Koivurova Oy | Wholesale & retail | 1997 |
| Markku Pallastie Oy | Transport & logistics | 1995 |
| Marsakari Oy | Manufacturing | 1995 |
| Martinniemen Kierrätys Oy | Wholesale & retail | 2025 |
| Martti ja Kaarina Junttari | Wholesale & retail | 1982 |
| Matti Alaviuhkola Ky | Other services | 2011 |
| Matto ja Maalaus J.Nikula Ky | Construction | 2009 |
| Medialect Oy | Professional & scientific | 1999 |
| Medibacka Oy | Health & social care | 2024 |
| Medica Borealis Oy | Health & social care | 2026 |
| Meerin Grilli Oy | Hospitality | 2018 |
| Meet The North Oy | Arts & recreation | 2026 |
| Mefs Oy | Professional & scientific | 2020 |
| Mellan Maito Oy | Agriculture & fishing | 2018 |
| Meri-Lapin Apupojat Oy | Administrative & support | 2021 |
| Meri-Lapin Autohuolto Ky | Other services | 2008 |
| Meri-Lapin Fysiovalmennus Oy | Arts & recreation | 2020 |
| Meri-Lapin Golfhalli Oy | Arts & recreation | 2014 |
| Meri-Lapin Hevospalvelu Oy | Arts & recreation | 2023 |
| Meri-Lapin Maanrakennus Ky | Construction | 2014 |
| Meri-Lapin Remonttipalvelu Ky | Construction | 2006 |
| Meri-Lapin Saha Oy | Manufacturing | 1991 |
| Meri-Lapin Sosiaalipalvelut Oy | Health & social care | 2014 |
| Meri-Lapin Taksit Oy | Transport & logistics | 1976 |
| Meri-Lapin Terveyspalvelut Oy | Health & social care | 2007 |
| Meri-Lapin Vakuutuspalvelut Oy | Financial services | 2021 |
| Meri-Lapin kaihdin palvelut Oy | Wholesale & retail | 2026 |
| Merilapin Auto Oy | Wholesale & retail | 1996 |
| Merilapin Laskenta Oy | Professional & scientific | 2013 |
| Mervi ja Seppo Väinämö Oy | Financial services | 1979 |
| MesPal Oy | Information & communication | 2008 |
| Mesopotamia Rantamaa Oy | Hospitality | 2005 |
| Mestaripesu Oy | Administrative & support | 1975 |
| Metallirakenne Heikki Häkkinen Ky | Manufacturing | 1982 |
| Metaru Oy | Construction | 2019 |
| Metor Avoin yhtiö | Construction | 2005 |
| Metsä Pirttimaa Oy | Agriculture & fishing | 1995 |
| Metsäpalvelu Kaikkonen Oy | Agriculture & fishing | 2014 |
| Metsäpalvelu Karjalainen Oy | Agriculture & fishing | 2024 |
| Metsäpalvelu Keskitalo Oy | Agriculture & fishing | 2024 |
| Metsäpalvelu Tervahauta Pertti Ky | Agriculture & fishing | 2010 |
| Metsäpalvelut Lohiniva Oy | Agriculture & fishing | 2020 |
| Meän Taksi Oy | Transport & logistics | 2024 |
| Meän tekniikka Oy | Wholesale & retail | 2018 |
| Mika Jussila Oy | Real estate | 2021 |
| Mika Kurtti Oy | Professional & scientific | 2022 |
| Mika Numminen Oy | Wholesale & retail | 1994 |
| Miknia invest oy | Real estate | 2021 |
| Miknia rakennus oy | Construction | 2021 |
| Milamet Ky | Manufacturing | 1979 |
| Mind Body Yoga Oy | Arts & recreation | 2017 |
| Mindovi Oy | Information & communication | 2026 |
| MiraSolutions Oy | Administrative & support | 2022 |
| Miroma Oy | Construction | 2006 |
| Miukin Kone Oy | Wholesale & retail | 2016 |
| Miviko Oy | Professional & scientific | 2008 |
| Modeon Oy | Professional & scientific | 2019 |
| Monax Consulting Oy | Hospitality | 2013 |
| Moonshine Safaris avoin yhtiö | Administrative & support | 1997 |
| Mopux Oy | Administrative & support | 1992 |
| MultiLocal Oy | Wholesale & retail | 2020 |
| Murskausliike Ossi Höynälä, kommandiittiyhtiö | | 1980 |
| Mustakumpu Oy | Agriculture & fishing | 2025 |
| Muuraus ja Laattatyö E. Lappalainen Kommandiittiyhtiö | Construction | 1983 |
| MySystems Ky | Information & communication | 2010 |
| Myllylahti Ky Autokoulu | Education | 1980 |
| MäkiJuntti Oy | Agriculture & fishing | 2020 |
| Mäkimaan Pyörä Oy | Wholesale & retail | 1980 |
| Mänty Coaching Oy | Arts & recreation | 2022 |
| NGR- Palvelu Oy | Transport & logistics | 2024 |