| Kotirintama ky | Administrative & support | 2006 |
| Kotiroka Foods Oy | Hospitality | 2025 |
| Kotiso Oy | Administrative & support | 2024 |
| Kotisoundi Oy | Real estate | 2022 |
| Kotivara Oy | Manufacturing | 1943 |
| Kotivara Yhtiöt Oy | Real estate | 1986 |
| Kotocode Oy | Information & communication | 2026 |
| Kotokas Oy | Real estate | 2024 |
| Kototek Oy | Hospitality | 2012 |
| Kotovaara Consulting Oy | Education | 2021 |
| Koukkuplus Suomi Oy | Other services | 2025 |
| Koulukadun Hammaslääkärit Oy | Health & social care | 1999 |
| Koulutus Excellence Oy | Education | 2024 |
| Koulutus- ja työnohjaus Ubuntu Oy | Education | 2022 |
| Koura Labs Oy | Information & communication | 2018 |
| Kourutek Oy | Construction | 2016 |
| Kouta Oulu Oy | Professional & scientific | 2016 |
| Koutsi Kakarinen Oy | Arts & recreation | 2025 |
| Koutsi hoitaa Oy | Financial services | 2021 |
| Kovalainen & Suni Osakeyhtiö | Professional & scientific | 1991 |
| Kovalauta Oy | Real estate | 2023 |
| Kovaporaus Oy | Construction | 2025 |
| Kovesu Oy | Financial services | 2009 |
| Kovinvest Oy | Professional & scientific | 2021 |
| Kovito Oy | Real estate | 2015 |
| Koy Hiukan Piha | Real estate | 2020 |
| Koy Inarin Korpituli | Real estate | 2019 |
| Koy Rukan tiira | Real estate | 2024 |
| Koy Urkintie | Real estate | 2021 |
| Kraaseli-Kiinteistöt Oy | Construction | 2024 |
| Kranbelts Oy | Manufacturing | 2023 |
| Kranu Oy | Information & communication | 2018 |
| Kraton Chemical Oy | Wholesale & retail | 2007 |
| Kreema Oy | Hospitality | 2015 |
| Krementor Oy | Professional & scientific | 2020 |
| Kristian Kuoksa Oy | Arts & recreation | 2022 |
| Kristiinan Klinikka Oy | Health & social care | 2013 |
| Krona Kapital Oy | Administrative & support | 2017 |
| Kuhako Oy | Professional & scientific | 2023 |
| Kuittirumba Oy | Professional & scientific | 2019 |
| Kuiva Telakka Oy | Real estate | 2024 |
| Kuiva ukko Oy | Professional & scientific | 2022 |
| Kuivaksen Leipomo Oy | Manufacturing | 1998 |
| Kuivas Kiinteistöt Oy | Real estate | 2007 |
| Kuivasjärven Kauppa Erkki Suvanto Ky | Wholesale & retail | 1982 |
| Kuivasjärven Ratsastuskoulu Oy | Arts & recreation | 2019 |
| Kuju Oy | Professional & scientific | 2024 |
| Kukka-Maaria Ky | Wholesale & retail | 1982 |
| Kukkakauppa Kanerva Ky | Wholesale & retail | 1993 |
| Kukkakauppa Mia-Maria Oy | Wholesale & retail | 2017 |
| Kukkakauppa Minna Ekdahl oy | Wholesale & retail | 2021 |
| Kukkapalvelu Ruusuliike Oy | Wholesale & retail | 2016 |
| KukkoLasse Oy | Administrative & support | 2019 |
| Kukkohovi Palvelut Oy | Administrative & support | 2010 |
| Kuljetin ja Hihnahuolto J. Tuominen Ky | Manufacturing | 2017 |
| Kuljetus Alaluusua Oy | Transport & logistics | 2023 |
| Kuljetus Arponen Ky | Transport & logistics | 1975 |
| Kuljetus H. Manninen Oy | Transport & logistics | 2026 |
| Kuljetus Jaakko Ikonen Ky | Transport & logistics | 2015 |
| Kuljetus Jap Oy | Transport & logistics | 2005 |
| Kuljetus Jukka Lämsä Oy | Transport & logistics | 2017 |
| Kuljetus Kaikkonen Ky | Transport & logistics | 1991 |
| Kuljetus Ketopojat Oy | Transport & logistics | 2021 |
| Kuljetus Liupek Ky | Transport & logistics | 2013 |
| Kuljetus M Koskela Oy | Transport & logistics | 2024 |
| Kuljetus M. Veikkola Oy | Transport & logistics | 2000 |
| Kuljetus Metsätähti Ky | Transport & logistics | 1995 |
| Kuljetus Niko Penttilä Oy | Transport & logistics | 2019 |
| Kuljetus Oulap Oy | Transport & logistics | 2000 |
| Kuljetus Rein Oy | Transport & logistics | 1997 |
| Kuljetus Romppainen Oy | Transport & logistics | 1997 |
| Kuljetus T. Iinatti Oy | Transport & logistics | 2013 |
| Kuljetus Tapojärvi Ky | Mining & quarrying | 1985 |
| Kuljetus Torvinen Oy | Transport & logistics | 2016 |
| Kuljetus Uutinen Oy | Transport & logistics | 1991 |
| Kuljetus ykkönen Oy | Transport & logistics | 2022 |
| Kuljetuskopla Ky | Transport & logistics | 1994 |
| Kuljetusliike E. Lepistö Oy | Transport & logistics | 1982 |
| Kuljetusliike Erkki Tolvanen kommandiittiyhtiö | Transport & logistics | 1980 |
| Kuljetusliike J. Pääaho Oy | Transport & logistics | 2013 |
| Kuljetusliike Jaakko Karhu Oy | Transport & logistics | 1981 |
| Kuljetusliike Jari Karjalainen Oy | Transport & logistics | 1996 |
| Kuljetusliike Kinnunen Oy | Transport & logistics | 1987 |
| Kuljetusliike Koivikko Ky | Transport & logistics | 2001 |
| Kuljetusliike M. ja R. Karjalainen Oy | Transport & logistics | 1979 |
| Kuljetusliike O. Pelkonen Oy | Transport & logistics | 1986 |
| Kuljetusliike Pelkoset Ky | Transport & logistics | 2000 |
| Kuljetusliike S. Keskitalo, Kommandiittiyhtiö | Transport & logistics | 1976 |
| Kuljetusliike S. Mustonen ky | Transport & logistics | 2003 |
| Kuljetusliike Tapio Posio Ky | Transport & logistics | 2007 |
| Kuljetusliike Veijo Lempinen Ky | Transport & logistics | 1998 |
| Kuljetuspalvelu H.Jaakola Ky | Transport & logistics | 2018 |
| Kuljetuspalvelu Heikkilä Oy | Transport & logistics | 2021 |
| Kuljetuspalvelu R. Pennanen Ky | Transport & logistics | 2013 |
| Kuljetuspolar Oy | Construction | 1964 |
| Kuljetusruutu Oy | Transport & logistics | 1994 |
| Kultainen Mallas Oy | Manufacturing | 2019 |
| Kultakamari Oy | Wholesale & retail | 2020 |
| Kultatie Holding Oy | Mining & quarrying | 2017 |
| Kultatie Oy | Mining & quarrying | 2017 |