| LVI-Liukku Ky | Construction | 1996 |
| LVI-Markkula R. Ky | Construction | 1971 |
| LVIS-Projektit Oy Imatra | Construction | 2018 |
| LVImatra Oy | Construction | 2018 |
| Laatu - Valinta Oy | Wholesale & retail | 2024 |
| Labaz Package Oy | Transport & logistics | 2023 |
| LadyMak Oy | Wholesale & retail | 1985 |
| Laipri Oy | Financial services | 1985 |
| Lakitoimisto Olli Ruokonen Ky | Professional & scientific | 1974 |
| Lammassaaren Veneveistämö Oy | Manufacturing | 1991 |
| Lammassaaren veneosuuskunta | Real estate | 1999 |
| Lapp-Impex Oy | Wholesale & retail | 2017 |
| Lappeenrannan Arvo-kiinteistöt Oy | Real estate | 2012 |
| Lares Finland Oy | Manufacturing | 2022 |
| Laskalmas Oy | Real estate | 1990 |
| Lecator Oy | Administrative & support | 2015 |
| Leino yhtiöt Oy | Other services | 2013 |
| Leontev Oy | Professional & scientific | 2020 |
| Lexlux Oy | Health & social care | 1998 |
| Lexpertiisi Asianajotoimisto Oy | Professional & scientific | 2015 |
| LiekinKieli Oy | Arts & recreation | 2024 |
| Life & Work Service Oy | Administrative & support | 2019 |
| LifeBreeze Oy | Mining & quarrying | 2024 |
| Liikunta- ja hyvinvointikeskus Voima Oy | Arts & recreation | 2015 |
| Liisanpuiston Lämpö Oy | Energy | 1978 |
| Liito-Oravat Oy | Health & social care | 2022 |
| Lingvo-centro Oy | Professional & scientific | 2017 |
| Linnansuon Leipomo Oy | Manufacturing | 2026 |
| Liusushi Oy | Hospitality | 2016 |
| LogoTex Oy | Wholesale & retail | 2004 |
| Lomakolmoset II Oy | Real estate | 1988 |
| Lomakolmoset III Oy | Real estate | 1988 |
| Lomasalkku Oy | Real estate | 2026 |
| Louhi Kivitasot Oy | Manufacturing | 1994 |
| Lounari Sushi Oy | Hospitality | 2021 |
| Lounaskahvila Kahvikatti Ky | Hospitality | 2017 |
| Lubava Oy | Hospitality | 2019 |
| Luonnonvalo Oy | Administrative & support | 2011 |
| Luontaistuote Apila Avoin yhtiö | Wholesale & retail | 1990 |
| Lure of Saimaa Oy | Administrative & support | 2025 |
| Luvamaa Oy | Wholesale & retail | 2019 |
| Lääkäripalvelu Satu Ojalainen Oy | Health & social care | 2004 |
| M&P Halinen Oy | Real estate | 1990 |
| M-Lift Kiinteistöt Oy | Real estate | 2019 |
| M-Lift Oy | Transport & logistics | 2008 |
| MA Kiinteistöasiantuntijat Oy | Real estate | 2022 |
| MB Arts Oy | Arts & recreation | 2020 |
| MCR One Oy | Information & communication | 2025 |
| MD-Koneistus Oy | Manufacturing | 2020 |
| MDI Service Oy | Other services | 2019 |
| MJ Oinonen Oy | Financial services | 1986 |
| MK-Leipomot Oy | Manufacturing | 2022 |
| MSH Adventures Oy | Education | 2024 |
| MT RaceTech Oy | Other services | 2024 |
| MVK Service Oy | Administrative & support | 2013 |
| Maalausliike E. Heiskanen Oy | Construction | 2004 |
| Maalausliike V. Lääperi Oy | Construction | 1982 |
| Maansiirto Backman Oy | Construction | 1984 |
| Maansiirto Pakkanen Oy | Construction | 1995 |
| Maansiirto Sakari Paukku Kommandiittiyhtiö | Construction | 1986 |
| Maansiirtoliike Ikävalko Oy | Construction | 1980 |
| Maansiirtoliike K ja V Anttonen Oy | Construction | 1986 |
| Maatila Hallikas Oy | Agriculture & fishing | 2026 |
| Mainostoimisto Dominus Oy | Professional & scientific | 2019 |
| Makes Stone Ky | Construction | 2012 |
| Makuu Eco Solutions Oy | Wholesale & retail | 2024 |
| Manerus Oy | Professional & scientific | 1992 |
| Maniserox Oy | Real estate | 2022 |
| Manlahden Metalli Oy | Manufacturing | 2000 |
| Mansikkalan Aikatimantti Helena Pulliainen Ky | Wholesale & retail | 1990 |
| Mansikkalan Kiinteistöhuolto Oy | Real estate | 1976 |
| Mansikkalan Makeat Oy | Wholesale & retail | 2025 |
| Mansikkalan Pullapuoti Ky | Wholesale & retail | 1986 |
| Mansikkalan toimitilat Oy | Real estate | 2017 |
| Marine & Consulting Piili Oy | Real estate | 1991 |
| Marja-Liisa Hallikas Ky | Wholesale & retail | 1991 |
| Marjut Kuvaja Oy | Other services | 2010 |
| Markkinointi Amoroso Oy | Professional & scientific | 2002 |
| Markmap Oy | Professional & scientific | 2008 |
| Marko ja Sirpa Tujula Ky | Wholesale & retail | 1994 |
| Marlon Movies Oy | Information & communication | 1989 |
| Mauri Manninen Ky | Professional & scientific | 1991 |
| Mecafin Oy | Wholesale & retail | 1996 |
| Media Star Oy | Information & communication | 2018 |
| MeilläOnOikeus Oy | Professional & scientific | 2021 |
| Meioma Oy | Administrative & support | 2026 |
| Memoria Oy | Other services | 1991 |
| MenoKumi Oy | Wholesale & retail | 2021 |
| Menoauto Oy | Wholesale & retail | 2017 |
| Menorengas Ky | Wholesale & retail | 1990 |
| Metalliproff Oy | Wholesale & retail | 2022 |
| Metsäkampa Oy | Agriculture & fishing | 2025 |
| Metsätyö ja Koneurakointi Moisio Kommandiittiyhtiö | Agriculture & fishing | 2007 |
| Mevia Oy | Construction | 2025 |
| Midell Oy | Wholesale & retail | 2008 |
| Miesperä A ja K Oy | Real estate | 2022 |
| Mikrotuki Hellman Oy | Information & communication | 1996 |
| Miksa-Tili Oy | Professional & scientific | 1993 |
| Mimoto Ky | Wholesale & retail | 2003 |
| MiniSampo Oy | Real estate | 2014 |