| Kuapo Oy | Information & communication | 2021 |
| Kub Group Oy | Construction | 2026 |
| Kubbe Oy | Professional & scientific | 2019 |
| Kucko No6 Oy | Information & communication | 2025 |
| Kudelma - kokonaisvaltaisen ja kestävän systeemisen muutoksen osuuskunta | Professional & scientific | 2023 |
| Kuggskär Oy | Real estate | 1971 |
| Kuha Oy | Health & social care | 2006 |
| Kuhhi Oy | Construction | 2025 |
| Kuikan Collective Osuuskunta | Professional & scientific | 2025 |
| KuikkArt Oy | Arts & recreation | 2025 |
| Kuikka Partners Oy | Professional & scientific | 2023 |
| Kuirinmäki Oy | Real estate | 2023 |
| Kuitikkaanlahden Vesiosuuskunta | Water & waste | 2008 |
| Kuitinkadun Pysäköinti Oy | Real estate | 1982 |
| Kuivaco Oy | Construction | 2024 |
| Kujala Invest Oy | Real estate | 2020 |
| Kukaco Oy | Manufacturing | 2022 |
| Kukkaiselämys Oy | Wholesale & retail | 2020 |
| Kukkakauppa Sitomo Outi Alanne Oy | Wholesale & retail | 2013 |
| Kukkakauppa Soukan Sydän Ky | Wholesale & retail | 2006 |
| Kukkaluuruu Oy | Wholesale & retail | 2026 |
| Kukkapysäkki Oy | Wholesale & retail | 2024 |
| Kukkar Invest Oy | Financial services | 2018 |
| Kukkaranta Oy | Administrative & support | 2026 |
| Kukkaserenadi Avoin yhtiö | Arts & recreation | 2017 |
| Kukkatalo Maritta Oy | Wholesale & retail | 2001 |
| Kukkujuujuu Oy | Health & social care | 2024 |
| Kukkumäen Kuljetus Oy | Transport & logistics | 2020 |
| Kulakit Oy | Real estate | 2017 |
| Kuljetus B.Tuure Oy | Transport & logistics | 2017 |
| Kuljetus HJK Oy | Transport & logistics | 1979 |
| Kuljetus Hakke Oy | Transport & logistics | 2018 |
| Kuljetus Juntuset Oy | Transport & logistics | 1980 |
| Kuljetus Jusa Oy | Transport & logistics | 2012 |
| Kuljetus Kuivanen Ky | Transport & logistics | 1961 |
| Kuljetus Lintukallio Oy | Transport & logistics | 2025 |
| Kuljetus Metsä Oy | Transport & logistics | 1989 |
| Kuljetus NPR Oy | Transport & logistics | 2013 |
| Kuljetus Orkamo Oy | Transport & logistics | 2008 |
| Kuljetus Oy Jyrki Murto | Transport & logistics | 1991 |
| Kuljetus Oy K. Vauhkonen | Transport & logistics | 1987 |
| Kuljetus Oy R. Ahtiainen | Transport & logistics | 1991 |
| Kuljetus P. Saarinen Oy | Transport & logistics | 1989 |
| Kuljetus Rahimu Oy | Transport & logistics | 2022 |
| Kuljetus Rinkinen Ky | Transport & logistics | 2014 |
| Kuljetus Sainio Oy | Transport & logistics | 2015 |
| Kuljetus T. Ojala Oy | Transport & logistics | 2006 |
| Kuljetus Team Virtanen Oy | Transport & logistics | 2005 |
| Kuljetus U. Hellsten Oy | Transport & logistics | 1995 |
| Kuljetus UHJ Oy | Transport & logistics | 1985 |
| Kuljetus- ja kiinteistöpalvelut Qvarnström Oy | Transport & logistics | 1989 |
| Kuljetuskaksikko Oy | Transport & logistics | 1984 |
| Kuljetuskeskus Oy Grani Ab Transportcentral | Transport & logistics | 1985 |
| Kuljetusliike A.E. Laine Oy | Transport & logistics | 1960 |
| Kuljetusliike E. Harnala Oy | Transport & logistics | 1994 |
| Kuljetusliike Eero Hakala Ky | Transport & logistics | 1988 |
| Kuljetusliike Gunnar Westerberg & Kumpp | Transport & logistics | 1961 |
| Kuljetusliike Harri Sandell Oy | Transport & logistics | 1994 |
| Kuljetusliike Hiekkaniemi & Kumpp. Oy | Transport & logistics | 1962 |
| Kuljetusliike J. Kuismanen Oy | Transport & logistics | 1995 |
| Kuljetusliike J.Keränen Oy | Transport & logistics | 2021 |
| Kuljetusliike Jukka Romu Oy | Transport & logistics | 1997 |
| Kuljetusliike K. Karlsson Oy | Transport & logistics | 1997 |
| Kuljetusliike Lasse Piippo Oy | Transport & logistics | 2018 |
| Kuljetusliike Merjanne Oy | Transport & logistics | 1978 |
| Kuljetusliike Pekka Harjanne Oy | Transport & logistics | 1997 |
| Kuljetusliike R. Sandell Oy | Transport & logistics | 2004 |
| Kuljetusliike Sakari Herrala Oy | Transport & logistics | 2000 |
| Kuljetusliike Timo Kuismanen Ky | Transport & logistics | 2005 |
| Kuljetuspalvelu MJ Oy | Transport & logistics | 2023 |
| Kuljetuspalvelu Rafat Oy | Transport & logistics | 2019 |
| Kuljetuspalvelut Kiireinen Oy | Wholesale & retail | 2004 |
| Kuljetustiimi Chellat Oy | Transport & logistics | 2021 |
| Kuljetustoiminta Oy Acetruckers Ltd | Transport & logistics | 1996 |
| Kulkijapoika Oy | Professional & scientific | 1992 |
| Kulkuvoima Oy | Other services | 2010 |
| Kullervo Holding Oy | Financial services | 2021 |
| Kulloo Services Oy | Real estate | 2014 |
| Kulmakaari Oy | Professional & scientific | 2000 |
| Kulta Creative Oy | Professional & scientific | 2020 |
| Kultahattu Capital Oy | Financial services | 2025 |
| Kultainen Ananas Oy | Other services | 2014 |
| Kultainen tuuli Oy | Financial services | 2022 |
| Kultaiset Pojat Oy | Wholesale & retail | 2012 |
| Kultasepänliike Meidän Sepät Ky | Wholesale & retail | 1984 |
| Kultatili Oy | Professional & scientific | 1987 |
| Kuluko Oy | Information & communication | 2024 |
| Kulutuspinta Oy | Wholesale & retail | 2024 |
| Kulvakko Oy | Professional & scientific | 1988 |
| Kumi Group Oy | Other services | 2022 |
| Kumitiili Finland Oy | Wholesale & retail | 2014 |
| Kumorion Platforms Oy | Information & communication | 2023 |
| Kumppanuuskoulut Oy | Real estate | 2019 |
| Kumpukaluste Oy | Manufacturing | 1992 |
| Kumpulainen Holding Oy | Financial services | 2026 |
| Kumura Consulting Oy | Professional & scientific | 2017 |
| Kunam OY | Information & communication | 2014 |
| Kund-o Suomi Oy | Information & communication | 2022 |
| Kuningatarniemi 137 Oy | Real estate | 2021 |
| Kuninkaansatama GP Oy | Financial services | 2022 |