| MP-Taipale Kommandiittiyhtiö | Other services | 1987 |
| MP-Teollisuus Oy | Financial services | 1993 |
| MP-Yhtymä Oy | Financial services | 2010 |
| MPH Racing Oy | Arts & recreation | 2019 |
| MPK-Asennus Oy | Other services | 2009 |
| MPM-Musiikki avoin yhtiö | Arts & recreation | 2002 |
| MPO Kiinteistöt Oy | Real estate | 1994 |
| MPO-Yhtiöt Oy | Financial services | 1998 |
| MPR Properties Oy | Financial services | 2018 |
| MPS Holding Oy | Professional & scientific | 1994 |
| MPS-Infra Oy | Construction | 2004 |
| MPT-Tools Avoin yhtiö | Wholesale & retail | 2007 |
| MPT-Trading Oy | Wholesale & retail | 2011 |
| MQ Group Oy | Administrative & support | 2021 |
| MR Consult&Holdings oy | Wholesale & retail | 2020 |
| MR Marketing & Business Consulting Oy | Financial services | 2019 |
| MRK Restaurants Oy | Hospitality | 2025 |
| MRT Engineering Oy | Manufacturing | 2019 |
| MS Customs Oy | Manufacturing | 2023 |
| MS Medi Oy | Health & social care | 2026 |
| MS Porras Oy | Professional & scientific | 2008 |
| MS-Invest Oy | Construction | 2017 |
| MSH Group Oy | Administrative & support | 2008 |
| MSH Tekniikka Oy | Manufacturing | 2024 |
| MSM Finland Oy | Construction | 2019 |
| MSRH Invest Oy | Professional & scientific | 2020 |
| MSc Control Oy | Administrative & support | 1987 |
| MSc Traction Oy | Professional & scientific | 1996 |
| MSc electronics Oy | Professional & scientific | 1985 |
| MT Audio Oy | Information & communication | 1991 |
| MT Business Coaching Oy | Professional & scientific | 2020 |
| MT Housing Oy | Real estate | 2010 |
| MT Industries Oy | Wholesale & retail | 2013 |
| MT Koulutus ja terapia Oy | Health & social care | 1994 |
| MT-kuljetus Oy | Transport & logistics | 2025 |
| MTB Aurora Oy | Arts & recreation | 2026 |
| MTL Crafts Oy | Information & communication | 2025 |
| MTL Suunnittelu Oy | Professional & scientific | 2019 |
| MTM Asennuspalvelu Oy | Construction | 2012 |
| MTM Kiinteistö Oy | Real estate | 1992 |
| Mtp-Konepaja OY | Manufacturing | 2009 |
| MTS-Group Oy | Construction | 2012 |
| MTT-Yhtiö Oy | Administrative & support | 1994 |
| Mttran OY | Hospitality | 2024 |
| MUKA VA Oy Visual Pleasure Ltd. | Professional & scientific | 2003 |
| MVGA Holding Oy | Financial services | 2025 |
| MVI Apparel Oy | Wholesale & retail | 2020 |
| MVP Ravintolat Oy | Hospitality | 2018 |
| Mvr-Yhtiöt OY | Financial services | 2023 |
| MVS-Supervision Oy | Professional & scientific | 2025 |
| MW Storage Nokia Oy | Energy | 2024 |
| MW Storage Nordic Oy | Energy | 2021 |
| MW Storage Nordic THREE Oy | Energy | 2024 |
| MW Storage Nordic TWO Oy | Energy | 2023 |
| My Elle OY | Hospitality | 2014 |
| MYOB Oy | Wholesale & retail | 2022 |
| MYYNTITULI Oy | Professional & scientific | 2018 |
| MaH Holding Oy | Financial services | 2021 |
| MaKa Trading Oy | Administrative & support | 2025 |
| MaLaTek Oy | Other services | 2026 |
| Maa Collective Oy | Manufacturing | 2021 |
| Maakunnan Notariaatti Oy | Real estate | 2008 |
| Maalari-Jyri Oy | Construction | 2021 |
| Maalarium Oy | Other services | 2022 |
| Maalaus J. Pääsky Ky | Construction | 1989 |
| Maalaus Sutina Oy | Construction | 2020 |
| Maalausliike Partanen Oy | Construction | 1993 |
| Maalausliike Pitävä Avoin yhtiö | Construction | 2024 |
| Maalausliike Tanhuanpää Oy | Construction | 1979 |
| Maalausliike Vainiomäki Oy | Construction | 1961 |
| Maalausliike Varion Oy | Construction | 2022 |
| Maalauspalvelu Forsman Oy | Real estate | 2022 |
| Maalauspalvelu Kotimaalaus Oy | Construction | 2024 |
| Maalauspalvelu Olli Hietanen Oy | Construction | 1989 |
| Maalikauppa Väritupa Oy | Wholesale & retail | 2006 |
| Maanoja Oy | Transport & logistics | 1983 |
| Maanrakennus Eero From Oy | Construction | 1996 |
| Maanrakennus Kamarjanskij Oy | Construction | 2018 |
| Maanrakennus Lasse Toikka Oy | Construction | 2019 |
| Maanrakennus Moreeni Oy | Construction | 1994 |
| Maanrakennus Rontu Oy | Construction | 2024 |
| Maanrakennus Terho Virtanen Oy | Construction | 1994 |
| Maarakennus Jari Takanen Oy | Construction | 1984 |
| Maarakennus Keko Oy | Construction | 2022 |
| Mabema holding Oy | Financial services | 2019 |
| Mabi Mobility Oy | Administrative & support | 2012 |
| Mac Mat Finland Oy | Wholesale & retail | 1993 |
| Macasiini Oy | Arts & recreation | 1992 |
| Machinery Acoustics Oy | Professional & scientific | 2009 |
| Macho Brothers Oy | Information & communication | 2016 |
| Macro Rocket Ltd. Oy | Financial services | 2023 |
| Macua Oy | Manufacturing | 2018 |
| Mad Finn Oy | Manufacturing | 2020 |
| Mad Professor Amplification Oy | Other services | 2006 |
| Madelaine Secondhand Shop, Anne-Elina Palonen Kommandiittiyhtiö | Wholesale & retail | 1997 |
| Maehold Oy | Financial services | 2024 |
| Maenae Oy | Professional & scientific | 2023 |
| MagStar Mining Oy | Professional & scientific | 2020 |
| Magentia Viestintä Oy | Professional & scientific | 2015 |
| Magia Music & Media Oy | Information & communication | 2015 |