| Karlstedt Consulting Oy | Professional & scientific | 2023 |
| Karttuma Group Oy | Real estate | 2025 |
| Kaski Works Oy | Construction | 2019 |
| Kiinteistö Oy Erkki Linkinen | Real estate | 1985 |
| Kiinteistö Oy Jänkhäjussit | Real estate | 1989 |
| Kiinteistö Oy Kaarinan Krossinkaari | Real estate | 2012 |
| Kiinteistö Oy Keskiläntie 7 | Real estate | 2021 |
| Kiinteistö Oy Krossinmutka | Real estate | 2016 |
| Kiinteistö Oy Liedon Kulkuripellontie 6 | Real estate | 2018 |
| Kiinteistö Oy Liedonristeys | Real estate | 2017 |
| Kiinteistö Oy Ohitustie | Real estate | 2024 |
| Kiinteistö Oy Otsonkatu 20 | Real estate | 1994 |
| Kiinteistö Oy Rasmella | Administrative & support | 1989 |
| Kiinteistö Oy Viitajärven Pyyntimiehet | Real estate | 1999 |
| Kiinteistöhuolto Savikko Oy | Administrative & support | 2019 |
| Kirsi Selovuo Oy | Health & social care | 2025 |
| Kirvestyö Rainio Oy | Construction | 1992 |
| Kone ja Autosähkö Hörkkö Oy | Other services | 2025 |
| Konekomppania Oy | Wholesale & retail | 2024 |
| Koneurakointi Jako Oy | Administrative & support | 2020 |
| Koneurakointi Lehto Oy | Construction | 2021 |
| Koneurakointi R & T Koivisto Oy | Construction | 2013 |
| Konsultointi Matti Telkki Oy | Information & communication | 1989 |
| Korte Audit Oy | Professional & scientific | 2021 |
| Kotiapu Loiste Oy | Real estate | 2009 |
| Kotimäen Huolto Oy | Administrative & support | 1980 |
| Kotimäen Tallit Oy | Agriculture & fishing | 1993 |
| Kotisiivous Pihlaja Oy | Administrative & support | 2013 |
| Kouvonen Yhtiöt Oy | Real estate | 2024 |
| Koy Michailowinkatu 5 | Real estate | 2015 |
| Koy Michailowinkatu 9 | Real estate | 2015 |
| Kratia Oy | Professional & scientific | 2020 |
| Kuja Engineering Oy | Information & communication | 2022 |
| Kuljetus Myntt Oy | Transport & logistics | 2025 |
| Kuljetusliike E. Mäki Oy | Transport & logistics | 1997 |
| Kultaseppä Kivikoski Ky | Manufacturing | 1973 |
| Kuvastaja Oy | Arts & recreation | 2002 |
| Kärkineliöt Oy | Real estate | 1989 |
| LS-Kiinteistöt Varsinais-Suomi Oy | Administrative & support | 2024 |
| LTI Holding Oy | Real estate | 2010 |
| LVI-Allu Oy | Construction | 2021 |
| LVI-Suunnittelu Mäkelä Oy | Professional & scientific | 2020 |
| LVI-asennus Jukka Kuusisto Oy | Construction | 1993 |
| LWM Consulting Oy | Financial services | 2023 |
| Laattahomma Oy | Construction | 2018 |
| Lalun Paja Oy | Professional & scientific | 2012 |
| Laskenta Vataja Oy | Professional & scientific | 2018 |
| Lauas Oy | Financial services | 2020 |
| Lauren Sales Oy | Financial services | 2020 |
| Leijona Maalaus Oy | Construction | 2022 |
| Leipurinne Oy | Professional & scientific | 1956 |
| Leppähaara Oy | Financial services | 2023 |
| Levin Revontuli Oy | Hospitality | 1987 |
| Liedon Kalliosora oy | Mining & quarrying | 2013 |
| Liedon Metalli ja Putkiasennus Oy | Construction | 1999 |
| Liedon Ravintola Oy | Hospitality | 2010 |
| Liedon henkilöstönvuokraus Oy | Manufacturing | 2021 |
| LinerSol Oy | Manufacturing | 2017 |
| LionArch Capital Advisors Oy | Financial services | 2019 |
| Litsan Autopalvelu Oy | Manufacturing | 2021 |
| LittRAK Oy | Professional & scientific | 2022 |
| LittoisLine Oy | Wholesale & retail | 2018 |
| Littoisten Autohuolto OY | Other services | 2014 |
| Littoisten Fysioterapia Ky | Health & social care | 1989 |
| Littoisten Liike Oy | Administrative & support | 2017 |
| Littoisten Polttopuu ja Monitoimi Oy | Manufacturing | 2017 |
| Littoisten Talotekniikka OY | Wholesale & retail | 2015 |
| Litu Oy | Real estate | 2014 |
| Liukas Medical Service Oy | Health & social care | 2018 |
| Lohja AAC Oy | Real estate | 2019 |
| Lokiko Horse Company Oy | Wholesale & retail | 2020 |
| Lootus-Puutarha Oy | Agriculture & fishing | 2014 |
| Lost Partners Oy | Information & communication | 2003 |
| Lounaskahvila Reivi Oy | Hospitality | 2017 |
| Lumil Oy | Manufacturing | 2021 |
| Lumo avoin yhtiö | Arts & recreation | 1993 |
| Luntaco Oy | Administrative & support | 2009 |
| Lyndon Oy | Information & communication | 2000 |
| Lämpö Nurmi Oy | Construction | 2006 |
| Lämpökallio Oy | Construction | 1992 |
| Länsi-Suomen Import & Export Oy | Wholesale & retail | 2021 |
| Länsi-Suomen Pikkubussit Oy | Transport & logistics | 2005 |
| Lääkäripalvelut Laine Oy | Health & social care | 2021 |
| MEP Software Consulting Oy | Information & communication | 2024 |
| MH-Toimi Oy | Wholesale & retail | 1996 |
| MJL Konsultointi Oy | Arts & recreation | 2023 |
| ML Ravintolat Oy | Hospitality | 2026 |
| MR Marine Oy | Construction | 1998 |
| MR-Motorsport Oy | Administrative & support | 2018 |
| Maalaus ja Rappaus Kiljander Oy | Construction | 2016 |
| Magua Oy | Financial services | 2007 |
| Makeis-Timppa Oy | Wholesale & retail | 1993 |
| Malobe Oy | Financial services | 2016 |
| Mariachi Holding Oy | Professional & scientific | 2020 |
| Mariachi Oy | Manufacturing | 2008 |
| Markkinointi Lempinen Oy | Wholesale & retail | 2002 |
| MatSulution Oy | Professional & scientific | 2025 |
| Matikainen Transport Oy | Transport & logistics | 2017 |
| Matti Katajainen Oy | Transport & logistics | 2010 |
| Mauri Lind Oy | Transport & logistics | 1994 |