| Kahvila Kiikku Oy | Hospitality | 2023 |
| Kahvila-konditoria Kakun Aika Ky | Hospitality | 2013 |
| Kai Ilkka Oy | Health & social care | 2000 |
| Kaicer Oy | Wholesale & retail | 2008 |
| Kaihdin Selkämaa Ky | Wholesale & retail | 2018 |
| Kaihdinliike Oulu Oy | Construction | 2024 |
| Kaihlasen Kaluste Avoin yhtiö | | 1982 |
| Kaijon Rohdos Oy | Wholesale & retail | 2014 |
| Kaijonharjun Pikkeri Kommandiittiyhtiö | | 1987 |
| Kaijonharjun fysioterapia Oy | Health & social care | 2020 |
| KaikuArt Oy | Arts & recreation | 2021 |
| Kailamed Oy | Wholesale & retail | 2018 |
| Kailatec Oy | Wholesale & retail | 2008 |
| Kaira Clothing Avoin Yhtiö | Wholesale & retail | 2014 |
| Kaira Digital Oy | Professional & scientific | 2023 |
| Kairan Kulkurit Oy | Wholesale & retail | 2011 |
| Kaismo Oy | Financial services | 2000 |
| Kaita fi Oy | Professional & scientific | 2008 |
| Kaitotek Oy | Information & communication | 2017 |
| Kajaste Oy | Information & communication | 2004 |
| Kajava Group Oy | Financial services | 2024 |
| Kaju Capital Oy | Financial services | 2026 |
| Kakkutalo.com Ky | Wholesale & retail | 2011 |
| Kaksin Meri-Lappi Oy | Health & social care | 2025 |
| Kaksin Nuorisopalvelut Oy | Health & social care | 2020 |
| Kaksin Oy | Health & social care | 2014 |
| Kaksin Pohjois-Pohjanmaa Oy | Other services | 2020 |
| Kaksin Varsinais-Suomi Oy | Health & social care | 2025 |
| Kakskutonen OY | Financial services | 2023 |
| Kaksois-Elokuvat Oy | Information & communication | 2025 |
| KalFys Oy | Health & social care | 2026 |
| KalaMafia Oy | Wholesale & retail | 2023 |
| Kalajoen Valko- ja Kem. Pesula Määttänen Ky | | 1978 |
| Kalaliike Jussi Haanpää Oy | Wholesale & retail | 2008 |
| Kaleva Media Oy | Information & communication | 2015 |
| Kaleva Oy | Information & communication | 1907 |
| Kalevan Autohuolto Ky | Other services | 2010 |
| Kalhut Oy | Wholesale & retail | 2020 |
| Kalimen Lehtopirtti Oy | Other services | 1998 |
| Kalivest Oy | Financial services | 2020 |
| Kallan Matkailu Oy | Transport & logistics | 1980 |
| Kalle Erkoma Ky | Other services | 2000 |
| Kalle Räisänen Oy | Mining & quarrying | 2021 |
| Kallen Kaluste Oy | Wholesale & retail | 2002 |
| Kallen Kalustetalo Oy | Real estate | 1971 |
| Kallen Pizzat Oy | Hospitality | 2024 |
| Kallen grilli Avoin yhtiö | Hospitality | 2003 |
| Kallio&Pulkkinen Oy | Health & social care | 2022 |
| Kallio-Kokko Capital Oy | Other services | 2025 |
| Kallion Komrex Oy | Construction | 2013 |
| Kallunki Holding Oy | Financial services | 2017 |
| Kalmec Oy | Wholesale & retail | 1999 |
| Kalne Oy | Professional & scientific | 2025 |
| Kalse-Holding Oy | Financial services | 1989 |
| Kaltio Rent Oy | Administrative & support | 2026 |
| Kaltio Technologies Oy | Information & communication | 2014 |
| Kalustepaletti Oy | Wholesale & retail | 1998 |
| Kamavi Invest Oy | Information & communication | 2022 |
| Kampaamo LS-Style Oy | Other services | 1992 |
| Kampaamo La Felicitá Ky | Other services | 1989 |
| Kampaamo Ull-Mari Ky | Other services | 1983 |
| Kampaamo-Parturi Salon Pipoli Kommandiittiyhtiö | Other services | 2006 |
| KamuApp Oy | Information & communication | 2025 |
| Kamula Consulting Oy | Information & communication | 2022 |
| Kandelberg & Matila Oy | Health & social care | 2012 |
| Kannisto Engineering Oy | Professional & scientific | 2016 |
| Kannuksen Tuulipuisto Oy | Energy | 2012 |
| Kansan Tahto Oy | Information & communication | 1949 |
| Kansipojantie Oy | Real estate | 1973 |
| Kantoraha Osakeyhtiö | Financial services | 2013 |
| Kanttarelli Invest Oy | Real estate | 2005 |
| Kaoliinijoki Oy | Wholesale & retail | 2021 |
| Kaoz clothing Oy | Manufacturing | 2019 |
| Kapasiteetti Oy | Arts & recreation | 2019 |
| Kapen metsäkonepalvelut Oy | Agriculture & fishing | 2019 |
| Kapillaari Sijoitus Oy | Financial services | 2004 |
| Kapitale Advisors Oy | Professional & scientific | 2026 |
| Kapparis Oy | Financial services | 2016 |
| Karaokebar Jousimies Oy | Hospitality | 2011 |
| KarboTech Oy | Professional & scientific | 2023 |
| Karhu Coaching Oy | Other services | 2020 |
| Karhu Lab Oy | Wholesale & retail | 2026 |
| Kari Kantakoski Oy | Financial services | 1994 |
| Kari Paloniemi Investments Oy | Financial services | 2025 |
| Kari Selmgren Konsultointi Oy | Professional & scientific | 1995 |
| Kari Simonen Palvelut Oy | Financial services | 2009 |
| Kari Ylitalo Ky | Information & communication | 1986 |
| Karicom Oy | Administrative & support | 2007 |
| Karipa Trading Oy | Wholesale & retail | 1994 |
| Karivuo Capital Oy | Professional & scientific | 2025 |
| Karjasillan Kulma Oy | Administrative & support | 2021 |
| Karjasillan Lääkäripalvelut Oy | Health & social care | 2007 |
| Karjatupa Avoin yhtiö | Hospitality | 1991 |
| Karkale Oy | Real estate | 1983 |
| Karlos Palvelut Oy | Administrative & support | 2019 |
| Karomia Oy | Other services | 2021 |
| Karpalotie Corporation Oy | Information & communication | 2025 |
| Karppinen & Karppinen Oy | Real estate | 2021 |
| Karri Rytilahti LKV Oy | Real estate | 2024 |
| Kartanokuva Oy | Wholesale & retail | 1993 |