| MP-Silmu Oy | Health & social care | 2012 |
| MPP Holding Oy | Financial services | 2007 |
| MPR Service Oy | Other services | 2009 |
| MPS-Motors oy | Wholesale & retail | 2011 |
| MPT Capital Oy | Real estate | 1991 |
| MR-Rengas Kommandiittiyhtiö | Wholesale & retail | 1982 |
| MR-Tekniikka Oy | Professional & scientific | 2020 |
| MRM Consulting Oy | Administrative & support | 2019 |
| MRP-Yhtiö Oy | Construction | 1985 |
| MRT Infra Oy | Construction | 1998 |
| MT Food avoin yhtiö | Wholesale & retail | 2007 |
| MTA SUOMI Oy | Administrative & support | 2021 |
| MVa Invest Oy | Real estate | 2018 |
| MaRa Ventures Oy | Arts & recreation | 2024 |
| Maailma Halal Kauppa Oy | Wholesale & retail | 2022 |
| Maajukka Oy | Construction | 2019 |
| Maakunnan Asunnot Oy | Real estate | 1992 |
| Maalaus Katainen Oy | Construction | 2024 |
| Maalausliike Hämeenkorpi Ky | Construction | 2004 |
| Maalausliike JKL Oy | Construction | 2025 |
| Maalausliike Pekkarinen Oy | Construction | 1982 |
| Maalausliike Sävysuora Oy | Construction | 1998 |
| Maalausliike Valko Oy | Construction | 2020 |
| Maanikkarit Oy | Construction | 1985 |
| Maansiirto E. Lahdenvesi Oy | Construction | 1983 |
| Maansiirto Harry Mäkelä Oy | Construction | 1990 |
| Maansiirtoliike Koivunen Oy | Construction | 2007 |
| Maasärmä Oy | Construction | 2001 |
| Maatalous Priima Oy | Agriculture & fishing | 2022 |
| Mad & Beauty Oy | Other services | 2023 |
| MadDog Invest Oy | Professional & scientific | 2022 |
| Magister Solutions Oy | Professional & scientific | 2005 |
| Magistro Oy | Professional & scientific | 2026 |
| Mahdollisuuksien Kodit Oy | Real estate | 2025 |
| Mahtava Group Oy | Wholesale & retail | 2024 |
| Mahtavat Experience Factory Oy | Wholesale & retail | 2018 |
| Mahtisonni Oy | Professional & scientific | 2024 |
| Maijatuuli Kommandiittiyhtiö | Manufacturing | 1999 |
| Mainers Oy | Financial services | 2021 |
| Maino Osk | Professional & scientific | 2011 |
| Mainos Jane Oy | Professional & scientific | 2000 |
| Mainospalvelu A. Laitinen Ky | Professional & scientific | 1996 |
| Mainostoimisto Halminen Oy | Information & communication | 2025 |
| Mainostoimisto Sitrusmedia Oy | Professional & scientific | 2019 |
| Mainostyö ja Kirjapaino Eloy Oy | Information & communication | 1995 |
| Major Staffing Oy | Administrative & support | 2021 |
| Make Style Ky, Markku Pirhonen | Wholesale & retail | 1980 |
| MakeeCo Oy | Professional & scientific | 2025 |
| Makenture Oy | Financial services | 2026 |
| Maksimivipu Holding Oy | Financial services | 2023 |
| Maku Wok Oy | Hospitality | 2023 |
| Malinen Yhtiöt Oy | Transport & logistics | 2017 |
| Malisko Oy | Real estate | 2017 |
| Maljonen Consulting Oy | Professional & scientific | 2024 |
| Mallakodit Oy | Real estate | 2025 |
| Mama Bear Capital Oy | Financial services | 2026 |
| Manage Applications Kommandiittiyhtiö | Information & communication | 1986 |
| Manalanpaja Oy | Arts & recreation | 2015 |
| Mango House Asian Restaurant Ab | Hospitality | 2013 |
| Manrami Oy | Administrative & support | 2015 |
| Mansion Travellers Oy | Administrative & support | 2016 |
| Manycures Oy | Health & social care | 2009 |
| Maptrans Oy | Education | 2009 |
| Mar-Len Mini-Laukku Oy | Wholesale & retail | 1989 |
| Mari-Ravintolat Oy | Hospitality | 2015 |
| Marika Kandell Oy | Health & social care | 2020 |
| Marika Mäkelä Oy | Construction | 1989 |
| Maritan Cafe Ky | Hospitality | 2013 |
| Maritimus Holding Oy | Financial services | 2020 |
| Marja- ja Vihannesmestarit Oy | Wholesale & retail | 2012 |
| Mark-Tilat Oy | Real estate | 1990 |
| Markkanen Sport Management Oy | Arts & recreation | 2017 |
| Markkinointi A.Honkonen Oy | Wholesale & retail | 2015 |
| Markkinointitoimisto Hyvähenki Oy | Professional & scientific | 2019 |
| Markkinointitoimisto TEKO Oy | Professional & scientific | 2012 |
| Markkinointiviestintä Pitenius Oy | Professional & scientific | 2020 |
| Markku Loukko Oy | Real estate | 1996 |
| Markus Tarkkala Oy | Information & communication | 2023 |
| Marmotail Oy | Real estate | 2007 |
| Marsh Education Design Oy | Professional & scientific | 2022 |
| Martin Tools Oy | Wholesale & retail | 2021 |
| Martti Murtola Ky | | 1989 |
| Masentia Oy | Wholesale & retail | 2015 |
| Masticap Oy | Professional & scientific | 1995 |
| Mathilde Holding Oy | Financial services | 2025 |
| Matias Kotilainen Oy | Agriculture & fishing | 2026 |
| Matias Trans Oy | Transport & logistics | 2015 |
| Matin Marjat Oy | Wholesale & retail | 2011 |
| Matlas Oy | Construction | 2025 |
| Matpeko Oy | Real estate | 1974 |
| Matsund Oy | Professional & scientific | 2024 |
| Mattec Oy | Construction | 2025 |
| Mattilanniemen Hotelli Oy | Hospitality | 1994 |
| Mattokymppi Oy | Wholesale & retail | 1994 |
| Mattopesula Pesumestarit Oy | Other services | 2014 |
| Maunonen group Oy | Real estate | 1994 |
| Mavapro Services Oy | Administrative & support | 2017 |
| Max Capital Oy | Professional & scientific | 2021 |
| Maya Lifestyle Oy | Other services | 2016 |
| Mce Invest Oy | Financial services | 2020 |