| KotiKukkolat Oy | Transport & logistics | 2021 |
| Koy Kauppatontti | Real estate | 2021 |
| Krouppi Oy | Real estate | 2022 |
| Kukka- ja hautauspalvelu Laurila Oy | Other services | 2025 |
| Kuljetus Hakala Ky | Transport & logistics | 1992 |
| Kuljetus Harri Mattila Avoin yhtiö | Transport & logistics | 2014 |
| Kuljetus Juurusoja Oy | Transport & logistics | 2010 |
| Kuljetus Jyrkinen Ky | Transport & logistics | 1987 |
| Kuljetusliike T. J. Nuutinen ky | Transport & logistics | 1980 |
| Kultapilven Markkinointi Oy | Wholesale & retail | 2011 |
| Kulttuurikaista Oy | Education | 2022 |
| Kumera Machinery Oy | Manufacturing | 1993 |
| Kuntoaskel Oy | Arts & recreation | 1997 |
| Kuohuja Oy | Wholesale & retail | 2020 |
| Kurkisaari Oy | Manufacturing | 2001 |
| Kuusisto & Partners Oy | Professional & scientific | 2017 |
| Kuusjoen tila oy | Agriculture & fishing | 2025 |
| Kylmis Oy | Arts & recreation | 2024 |
| Kylmäkosken Aseman Vesiosuuskunta | Water & waste | 1995 |
| Kylmäkosken Erikoismoottori Oy | Manufacturing | 1989 |
| Kylmäkosken Jauhemaalaus Oy | Manufacturing | 2008 |
| Kylmäkosken Koskipirtti Avoin yhtiö | Hospitality | 1994 |
| Kylmälaite Laakkonen Oy | Construction | 2013 |
| Kymppi-Kiinteistöt, Toijala Oy | Real estate | 1999 |
| Kymppi-Maukkaat Oy | Manufacturing | 1999 |
| Kyrölä Kuljetus Oy | Transport & logistics | 2013 |
| LVI - TOIJALA Oy | Construction | 2008 |
| LVI Hakonen Oy | Construction | 2021 |
| LVI-Ropa Oy | Construction | 2022 |
| LVI-Talli Oy | Construction | 2014 |
| LVI-Tohtori Oy | Construction | 2019 |
| LVI-toimisto Akair Oy | Professional & scientific | 1990 |
| Laamec Ky | Manufacturing | 1987 |
| LaatuJOPI Oy | Construction | 2015 |
| Laatupalkinto Virtanen Oy | Wholesale & retail | 2010 |
| Lampén Company Oy | Information & communication | 2002 |
| Lastech Automation Oy | Professional & scientific | 2018 |
| Lato Caravan Oy | Hospitality | 2024 |
| Laukeelan Väri ja Rauta Ky | Wholesale & retail | 1977 |
| Lavola Consulting Oy | Professional & scientific | 2025 |
| Lecas Asiantuntijapalvelut Oy | Professional & scientific | 2021 |
| Lehtia Oy | Real estate | 2021 |
| Leifinn Oy | Manufacturing | 1988 |
| Leinonen Investment Holding Oy | Financial services | 2020 |
| Leipomo Niemipelto Avoin yhtiö | Wholesale & retail | 2000 |
| Lemberg Aviation Oy | Administrative & support | 2008 |
| Lempi & Aukusti Oy | Hospitality | 2011 |
| Lento Consulting Oy | Professional & scientific | 2018 |
| Leomuovi Oy | Manufacturing | 2001 |
| Levitac Oy | Other services | 2025 |
| Levokas Oy | Administrative & support | 2018 |
| Liikehtivä Oy | Transport & logistics | 2008 |
| Liukkosen Ruoppauspalvelu Oy | Construction | 2003 |
| Lkv Kiinteistötoimisto T. Pirilä Ky | Real estate | 1987 |
| Logistiikkalinkki STM Oy | Transport & logistics | 2008 |
| Lokoloma Oy | Hospitality | 1992 |
| Los Tapahtumos Oy | Professional & scientific | 2000 |
| Lounas-Leidit Ky | Hospitality | 1998 |
| Lounaspirtin Pitoplikat Oy | Hospitality | 2021 |
| Lovena Oy | Health & social care | 2006 |
| Loveta Oy | Information & communication | 2025 |
| Luoverso Oy | Education | 2026 |
| Luukkanen & Myllymäki | Wholesale & retail | 2020 |
| Lämpöpumppupalvelu Porttikivi Oy | Construction | 2018 |
| M Keinonen Oy | Professional & scientific | 2022 |
| M&M Curry 510 Oy | Hospitality | 2022 |
| M.A saneeraus Oy | Construction | 2024 |
| M/S Kimalle Oy | Hospitality | 2026 |
| MB-varaosat ja huolto Venetmäki Oy | Other services | 1986 |
| MK-taitorakenne Oy | Construction | 2026 |
| MN Composites Oy | Manufacturing | 2026 |
| Moitek Ky | Wholesale & retail | 1997 |
| MR-myynti Oy | Wholesale & retail | 2016 |
| MV Energy Balance Oy | Other services | 2021 |
| MW Group Oy | Wholesale & retail | 2023 |
| Maa- ja Viherrakennus Rämö Oy | Construction | 1990 |
| Maalaus ja saneeraus LH Oy | Construction | 2023 |
| Maanrakennus Karirinne Ky | Construction | 2000 |
| Maanrakennus Lännenpoika Oy | Construction | 2016 |
| Maanrakennus M. Lajusuo Oy | Construction | 2021 |
| Maanrakennus Passi Oy | Administrative & support | 1995 |
| Maansiirto Knuutila Oy | Construction | 1991 |
| Maansiirtoliike Holma Oy | Construction | 2014 |
| Mahlawood Oy | Agriculture & fishing | 2026 |
| Maileritalot Oy | Wholesale & retail | 1978 |
| Mainosmesta Ky | Manufacturing | 1991 |
| Malo Ky | Manufacturing | 1973 |
| Malokiinnike Oy | Manufacturing | 2020 |
| Malotalo Oy | Real estate | 1988 |
| Mana Platforms Oy | Information & communication | 2025 |
| Marina Belle vue Oy | Real estate | 2017 |
| Markkinointi Kiiskinen Oy | Wholesale & retail | 1988 |
| Markkinointitoimisto Liike Oy | Professional & scientific | 2004 |
| Masila Oy | Real estate | 2007 |
| Mattila-Yhtymä Lehmus ja Kumpp. | Wholesale & retail | 1959 |
| Mecanor Oy | Professional & scientific | 1992 |
| Mescon Oy | Real estate | 2021 |
| Metallityö E. Mattila Oy | Manufacturing | 1996 |
| Metelmo Oy | Professional & scientific | 2010 |
| Metsäkunkku Oy | Agriculture & fishing | 2022 |