| Kesälahden Koneasennus Oy | Other services | 2016 |
| Kiinteistö Oy Iso Kylätie 47 | Real estate | 2007 |
| Kiinteistö Oy Nilsiän Koivulantie 1 | Real estate | 2001 |
| Kiinteistö Oy Pornaisten Moreenitie | Real estate | 2009 |
| Kiinteistö Oy Porvoon Nesteentie | Health & social care | 2017 |
| Kiinteistö Oy Pyhän Sigfridintie 13 | Real estate | 1997 |
| Kiinteistö Oy Sommarhaga | Real estate | 1989 |
| Kiinteistö Oy Westerhaga | Real estate | 1989 |
| Kiinteistöhuolto Toivonen Oy | Administrative & support | 1995 |
| Kiinteistöosakeyhtiö Sipoon Jussaksentie 14 | Real estate | 2015 |
| Kiinteistöosakeyhtiö Sipoon Jussaksentie 18 | Real estate | 2015 |
| Kilpakumppanit Oy | Professional & scientific | 2016 |
| KirpunKoti Oy | Arts & recreation | 2018 |
| Kitek oy | Construction | 2022 |
| Kivityö Brosman Ky | Construction | 2004 |
| Koivutek Oy | Administrative & support | 2016 |
| Kolme Cosmetics Oy | Manufacturing | 2018 |
| Kone ja kiinteistö M.Borg Oy | Professional & scientific | 2021 |
| Konepalvelu D. Ingman Oy | Construction | 1994 |
| Kontel OY | Wholesale & retail | 2021 |
| Kotiapu Hemma Bäst Oy | Health & social care | 2021 |
| Kratai Oy | Hospitality | 2013 |
| Krizia Oy Helena Hagman | Wholesale & retail | 1980 |
| Kukkatarha Skogberg Oy Ab | Agriculture & fishing | 2025 |
| Kuljetus Oy Turpeinen | Transport & logistics | 1994 |
| Kuljetus S. Wiik Oy | Transport & logistics | 2002 |
| Kuljetusliike Jouni Laine Avoin yhtiö | Transport & logistics | 2002 |
| Kuljetusliike Stig Skogster Ky Kb | Transport & logistics | 1992 |
| Kuljetusliike Veikko S. Rahkonen Ky | Transport & logistics | 1960 |
| Kulkuset oy | Transport & logistics | 2020 |
| Kunnon pohja Oy | Real estate | 2023 |
| Kylmäkonehuolto J. Varis Oy | Other services | 1989 |
| Kyyveden Matkailu Oy | Hospitality | 2025 |
| L-Palvelut Oy | Construction | 1998 |
| LD Tuotantoyhtiö Oy | Information & communication | 2026 |
| LM Kattosaneeraus Oy | Construction | 2019 |
| LVI-Ala Kemppainen Oy | Construction | 1995 |
| LVI-Lehto Oy | Construction | 2011 |
| Lakeside Ventures Oy | Construction | 2023 |
| Lakiasiaintoimisto Knuuti Ky | Professional & scientific | 2002 |
| Lauri Losio Oy | Transport & logistics | 2001 |
| Leaders' Studio Company oy | Professional & scientific | 2024 |
| Learning Media Finland Oy | Education | 2017 |
| Leiex Oy | Financial services | 2000 |
| Lift Crew Oy | Manufacturing | 2020 |
| Liljåås Oy/Ab | Arts & recreation | 2014 |
| Lippu ja Nuppi Oy | Construction | 2025 |
| Logegården Ab | Real estate | 1985 |
| Logista Oy | Manufacturing | 2022 |
| Lotworn Oy | Information & communication | 2025 |
| Lunki Ankka Holding Oy | Financial services | 2021 |
| Luodent Oy | Health & social care | 2013 |
| Lähimaalaus Oy - Närmåleri AB | Construction | 2005 |
| Lähisalit Kerava Oy | Arts & recreation | 2024 |
| Lämpöpumppupiste Suomi Oy | Construction | 2012 |
| M&K Spin Oy | Administrative & support | 2025 |
| MAI Invest Oy | Professional & scientific | 2012 |
| MK Steel Oy | Manufacturing | 2008 |
| ML Invest & Finance Oy | Financial services | 2013 |
| MLC Kuljetus Oy | Transport & logistics | 2024 |
| MLH Group Oy | Construction | 2026 |
| MOKH.RQ.PALVELU Oy | Transport & logistics | 2026 |
| MPK-myynti Oy | Professional & scientific | 2024 |
| MR Urheilu Oy | Financial services | 2024 |
| Mtm-Autoparts OY | Wholesale & retail | 2020 |
| Maa ja metsäpalvelu Lindqvist Oy | Wholesale & retail | 2024 |
| MaaKarrit Oy | Real estate | 2022 |
| Maailmanparannustoimisto Oy | Professional & scientific | 2020 |
| Maan Lämpö Oy | Construction | 2008 |
| Maanrakennus A. Sallinen Oy | Construction | 1999 |
| Maanrakennus JoSi Oy | Construction | 2021 |
| Maanrakennus Wiik Oy Ab | Construction | 2009 |
| Mac Set Ladontapalvelut Oy | Manufacturing | 1993 |
| Magnus Wikström Media Ab | Information & communication | 2023 |
| Majahaka Oy | Real estate | 2026 |
| Malmin Tietotaito Oy | Professional & scientific | 1987 |
| Managementum Oy | Professional & scientific | 2007 |
| Manhelp Oy | Professional & scientific | 1996 |
| Mannocon Oy | Professional & scientific | 2024 |
| Marcante Oy | Hospitality | 2002 |
| Marcatell Oy | Administrative & support | 2022 |
| Marco Dahlstedt-Arjen Sankari oy | Administrative & support | 2024 |
| Marikan Puutarhapalvelut Perenna & Penkki Oy | Administrative & support | 2023 |
| Marine Survey & Superintendency Services Oy | Professional & scientific | 2017 |
| Martinkylän kuljetus Oy | Transport & logistics | 2003 |
| Master Leader Academy Oy | Education | 2024 |
| Master Sweet Oy | Manufacturing | 2026 |
| Matbacka Capital Oy | Financial services | 2018 |
| Merclean Oy | Administrative & support | 2025 |
| Merivar Oy | Manufacturing | 2023 |
| Mervin Consulting Oy | Professional & scientific | 2015 |
| Metsä Matikainen Oy | Agriculture & fishing | 2015 |
| Mikromar Oy | Construction | 2008 |
| Moderno e Elegante pl Oy | Wholesale & retail | 1997 |
| Moen Consulting Ab | Professional & scientific | 2007 |
| Monikkonur Oy | Administrative & support | 2022 |
| Mother's Milk Beverages Oy | Wholesale & retail | 2013 |
| Musiikkituotanto Eat This Music Oy | Information & communication | 1998 |
| Männynhavu Oy | Administrative & support | 2025 |
| Männynhavu Palvelut Oy | Wholesale & retail | 2011 |