| Kahvila Mezaia Cafe Oy | Hospitality | 2021 |
| Kahvila-Lounasravintola Belinda Ky | Hospitality | 1991 |
| Kai Laaksonen Oy | Financial services | 1985 |
| Kai Resta Co Oy | Hospitality | 2021 |
| Kaihdin ja Markiisi Lahti Oy | Wholesale & retail | 2010 |
| Kailla Digital Oy | Professional & scientific | 2022 |
| Kainulainen Invest Oy | Real estate | 2020 |
| Kaivola Consulting Oy | Professional & scientific | 2023 |
| Kaivolan Kuljetus Oy | Transport & logistics | 1970 |
| Kaivotek Finland Oy | Construction | 2020 |
| Kajanor Oy | Manufacturing | 1987 |
| Kajklan Oy | Administrative & support | 1991 |
| Kajon Kulma Oy | Real estate | 2021 |
| Kalakuksa Oy | Agriculture & fishing | 2025 |
| Kalevan Kaivajat Oy | Financial services | 2021 |
| Kalkotek oy | Construction | 2025 |
| Kalliokuusi Oy | Construction | 2022 |
| Kalliolan Kaivin Oy | Construction | 2021 |
| Kalliolehto Oy | Education | 2023 |
| Kaltek Ky | Professional & scientific | 2017 |
| Kaluste Sivenius Ky | Manufacturing | 1981 |
| Kaluste-Hannula Oy | Wholesale & retail | 2012 |
| KalusteNet Oy | Wholesale & retail | 2021 |
| Kalustehalli Kallio Oy | Wholesale & retail | 1979 |
| Kalusteliike Ora Oy | Wholesale & retail | 2024 |
| Kalusterinki Oy | Professional & scientific | 2013 |
| Kameravarustelu JK Oy | Other services | 2022 |
| Kamlem Oy | Information & communication | 2020 |
| Kamppani Oy | Professional & scientific | 2008 |
| Kana & Smash Oy | Hospitality | 2026 |
| Kanavan Lasimestari Oy | Wholesale & retail | 2019 |
| KanttiKulmala Oy | Financial services | 2026 |
| Kanttis Oy | Wholesale & retail | 2014 |
| Kapanala Sisustusarkkitehdit Oy | Professional & scientific | 2013 |
| Kapata Oy | Financial services | 1997 |
| Kapustapuu Oy | Construction | 2024 |
| Karavaanipaja Lahti Oy | Other services | 2022 |
| Karavaanitaivas Oy | Other services | 2023 |
| Karen Oy | Construction | 1993 |
| Kari Karjalainen Music Oy | Information & communication | 2017 |
| Kari Rilasmaa Ky | Wholesale & retail | 1986 |
| Kari T Räsänen Ky | Transport & logistics | 1996 |
| Kari-Finn Oy | Manufacturing | 2008 |
| Kariniemen grilli oy | Hospitality | 2014 |
| Karirakenne Oy Rkl | Construction | 2004 |
| Kariston Pesula Ay | Other services | 2016 |
| Karjalan Karhu Oy | Administrative & support | 2024 |
| Karuselli Ravintolat Oy | Hospitality | 2023 |
| Kaseikko Oy | Agriculture & fishing | 2020 |
| Kasi-Biljardi Oy | Hospitality | 1990 |
| Kasins Oy | Manufacturing | 1995 |
| Kasno OY | Professional & scientific | 2015 |
| Kastanja-Kiinteistöt Oy | Real estate | 1987 |
| Kasvun kehä Oy | Health & social care | 2023 |
| Kasvunpaikka Oy | Professional & scientific | 1987 |
| Kasvuraketti Oy | Professional & scientific | 2002 |
| Kasvuverstas Oy | Professional & scientific | 2019 |
| Katajakunnas Oy | Health & social care | 1998 |
| Katasalo Oy | Wholesale & retail | 2003 |
| Katto Kuntoon Jukka Rämö Oy | Construction | 2009 |
| KattoCenter Pirkanmaa Oy | Construction | 2025 |
| Kattokorento Oy | Construction | 2025 |
| Kauhakulma Oy | Real estate | 2006 |
| Kauneushoitola Sirkka Aitala Oy | Other services | 2016 |
| Kauneuskeskus The Place Oy | Other services | 2022 |
| Kauneuskeskus UusLook Oy | Other services | 2026 |
| Kauneuspalvelu TJKJ Oy | Other services | 2022 |
| Kauppakeskus Grand Oy | Real estate | 2005 |
| Kauppayrjö Oy | Manufacturing | 1997 |
| Kauppias Somervaara Oy | Wholesale & retail | 2021 |
| Kaurapulssi Ky | Manufacturing | 2017 |
| Kausti Invest Oy | Financial services | 2026 |
| Kavako Oy | Professional & scientific | 2023 |
| Kehityshyppy Oy | Professional & scientific | 2008 |
| Keikkamies Ky | Construction | 2003 |
| Keikkaseppä Weckman Oy | Manufacturing | 1985 |
| Keinäsen Kuljetusliike Oy | Transport & logistics | 1996 |
| Keisarin Posliini OY | Wholesale & retail | 2006 |
| Keittiöasennus Kare Oy | Construction | 1995 |
| Keittiösuunnittelu ja -asennus O. Timonen Oy | Construction | 2013 |
| Kelo-Marketing Oy | Professional & scientific | 1983 |
| Kempiiri Oy | Wholesale & retail | 1977 |
| Kempinvest Oy | Professional & scientific | 2005 |
| Kempower International Oy | Administrative & support | 2023 |
| Kempower Oyj | Manufacturing | 2017 |
| Kemppi Group Oy | Manufacturing | 2011 |
| Kemppi Oy | Manufacturing | 2006 |
| Kemppitalli Oy | Arts & recreation | 1983 |
| Kemptron Oy | Manufacturing | 2024 |
| Kenkä-Opaali Oy | Wholesale & retail | 1992 |
| Kepakko Oy | Information & communication | 1990 |
| Kerinkallion pienryhmäkoti Oy | Health & social care | 2021 |
| Keski-Luopa Konsultointi Oy | Health & social care | 1992 |
| Keski-Suomen Henkilöstöapu Oy | Administrative & support | 2023 |
| Keskusmusiikki Lahti Oy | Wholesale & retail | 2000 |
| Keskustaravintolat H&G Oy | Hospitality | 1989 |
| Kesäpurje Oy | Arts & recreation | 2008 |
| KetRak Oy | Construction | 2020 |
| Ketomaan Kuusi Oy | Wholesale & retail | 2025 |
| Kexa Oy | Real estate | 1987 |