| Kivimäki Invest Oy | Real estate | 2016 |
| Kiviniemi Oy | Real estate | 1930 |
| Kivistön Karhu Oy | Real estate | 2016 |
| Kivistön Kunkku Oy | Hospitality | 2021 |
| Kivistön Putkijäte Oy | Water & waste | 2013 |
| Kivitikki Oy | Construction | 2003 |
| Kivituote Ylitalo Oy | Manufacturing | 2004 |
| Kivityö Tori Oy | Construction | 2024 |
| Kiviä Taskuun Holding Oy | Financial services | 2022 |
| KiyhtMH Ky | Real estate | 2012 |
| Kiyma oy | Wholesale & retail | 2022 |
| Kjellman Capital Ab | Professional & scientific | 2000 |
| Kkm invest Oy | Professional & scientific | 2024 |
| Klamilan Rantapartio Oy | Real estate | 1990 |
| Klamux Oy | Construction | 2025 |
| Klanga Oy | Professional & scientific | 2016 |
| Klastom Oy | Real estate | 2025 |
| Kliin Oy | Other services | 2022 |
| Klipstar Service Management Oy | Transport & logistics | 2026 |
| Klistec Oy | Other services | 2015 |
| Kloku Oy | Wholesale & retail | 2023 |
| Klymene Holding Oy | Financial services | 2026 |
| Knaans Oy | Information & communication | 2022 |
| Knabo Clothing Oy | Manufacturing | 2019 |
| Knief Investment Oy | Professional & scientific | 2010 |
| Knippu Oy | Wholesale & retail | 2017 |
| Knoobus Oy | Construction | 2015 |
| Knorring OY AB | Wholesale & retail | 1954 |
| KoBu Rakennus Oy | Construction | 2019 |
| KoNy Oy | Real estate | 2021 |
| KoTu Oy | Professional & scientific | 2018 |
| Kobutor Oy | Hospitality | 2026 |
| Kodal Oy | Information & communication | 2020 |
| Kodin Laatupiste Oy | Construction | 2016 |
| Kodin Mittakaluste VMK Oy | Wholesale & retail | 1997 |
| Kodin Säde Oy | Health & social care | 2025 |
| Kodin Sähkö Hki Oy | Construction | 2013 |
| Kodin Turvapalvelu-KTP Oy | Administrative & support | 1997 |
| Kodinelektroniikan Käyttöapu Valtonen Oy | Education | 2013 |
| Kodinkonehuolto M. Maristo Ky | Other services | 2004 |
| Kodinkonehuolto V. Toivanen Avoin yhtiö | Other services | 1999 |
| Kodit kunnossa oy | Construction | 2019 |
| Kohdehallinta 24/7 Oy | Real estate | 2026 |
| Koherent Oy | Manufacturing | 2019 |
| Kohkaus Oy | Financial services | 2024 |
| Koho Visuals Oy | Professional & scientific | 2021 |
| Koips Tekonurmi Oy | Real estate | 2012 |
| Koirakeidas Oy | Other services | 2007 |
| Koirametsä Tassula Oy | Arts & recreation | 2021 |
| Koit Consulting Oy | Professional & scientific | 2026 |
| Koitonlinna Oy | Education | 2017 |
| Koivikko Invest Oy | Financial services | 2023 |
| Koivu Isännöinti Oy | Real estate | 2005 |
| Koivu-Yhtiöt Oy | Real estate | 1972 |
| Koivuhaan Autokatsastus Oy | Professional & scientific | 2008 |
| Koivuhaan Kukkakauppa Oy | Wholesale & retail | 2011 |
| Koivuhaan Toimitilat Doro Oy | Real estate | 2025 |
| Koivuhuone Oy | Hospitality | 2001 |
| Koivupuistontie 34 Oy | Real estate | 1991 |
| Kojalait Oy | Transport & logistics | 1991 |
| Kokea Oy | Professional & scientific | 2024 |
| Kokemuskauppa Oy | Wholesale & retail | 2008 |
| Koketti Ky | Wholesale & retail | 1982 |
| Kokko Holding Oy | Financial services | 2023 |
| Kokkonen Cfood Oy | Wholesale & retail | 2013 |
| Kokkonen Holding Oy | Financial services | 2018 |
| Koko-Saneeraus Oy | Construction | 2024 |
| Kokodiili Oy | Construction | 1993 |
| Kokox Oy | Arts & recreation | 2022 |
| Kokvi Oy | Administrative & support | 2013 |
| Kolarikorjaukset T Parviainen Oy | Other services | 2002 |
| Kole Consulting Oy | Arts & recreation | 2026 |
| Koli's grilli & kahvila Oy | Professional & scientific | 2011 |
| Kolin Hotellikiinteistö Oy | Real estate | 2007 |
| Kollifox Oy | Wholesale & retail | 2020 |
| Kolme Vuodenaikaa Oy | Administrative & support | 2001 |
| Kolmen siskon pizza OY | Hospitality | 2024 |
| Kolmiorakenne Oy | Construction | 2004 |
| Kolo ja Kaato Oy | Agriculture & fishing | 2021 |
| Koloni Ky | Transport & logistics | 2012 |
| Koltax Oy | Transport & logistics | 2016 |
| Koltushi Development Oy | Real estate | 2019 |
| Komamedia Oy | Professional & scientific | 2017 |
| Komfovent Oy | Wholesale & retail | 2017 |
| Kommandiittiyhtiö Filmipiste Jyrki Innamaa | Information & communication | 1973 |
| Kompagniet Sales Oy | Wholesale & retail | 2003 |
| Konalanvuoren Lämpö Oy | Real estate | 1962 |
| Konart Oy | Construction | 2018 |
| Kone & Rakennus Mustonen Oy | Construction | 2011 |
| Kone Konkarit Oy | Other services | 2013 |
| Kone-Keskis Oy | Administrative & support | 1999 |
| Konehuolto Timo Suomi Ky | Other services | 1986 |
| Konekauha Oy | Construction | 1960 |
| Konemen Oy | Manufacturing | 2026 |
| Konemonikko Oy | Professional & scientific | 2004 |
| Konepalvelut Tapani Oy | Administrative & support | 2020 |
| Konerinki Oy | Construction | 2005 |
| Konesi oy | Administrative & support | 2011 |
| Konetyö Villikka Oy | Construction | 2021 |
| Koneurakointi Juslin Oy | Construction | 2025 |