| Kaarina Consulting Oy Ltd | Administrative & support | 2013 |
| Kaarinan Fitness Center Avoin yhtiö | Arts & recreation | 1997 |
| Kaarinan Kuntoklubi Oy | Arts & recreation | 2005 |
| Kaarinan Mansive Oy | Construction | 1994 |
| Kaarinan Masa Oy | Real estate | 1992 |
| Kaarinan Priki Oy | Real estate | 1991 |
| Kaarinan Yrityspalvelut Oy | Construction | 1990 |
| Kaarinan liikuntahalli Oy | Real estate | 2022 |
| Kadimet Oy | Hospitality | 2006 |
| Kaerlan Kumi Oy | Wholesale & retail | 1989 |
| Kaffela Lara Ky | Transport & logistics | 2010 |
| Kafé Gadolinia Kommanditbolag | Hospitality | 1986 |
| Kahatia Oy | Real estate | 2015 |
| Kahdeksan Sillan Ravintolat Oy | Hospitality | 2021 |
| Kahdeksas Yritys Oy | Information & communication | 2024 |
| Kahie Oy | Transport & logistics | 2023 |
| Kahra Group Oy | Professional & scientific | 2023 |
| Kahvila Mirimari Oy | Hospitality | 2023 |
| Kahvila Oksi Oy | Real estate | 2019 |
| Kahvila-Ravintola Perno Oy | Hospitality | 1990 |
| Kahvila-konditoria Oran avoin yhtiö | Manufacturing | 1998 |
| Kahvitukku ABI Oy | Wholesale & retail | 2018 |
| Kaihdinasennus Anttonen Ky | Wholesale & retail | 1982 |
| Kaihdinliike Sandberg Oy | Wholesale & retail | 2003 |
| Kaihdinpalvelu Höglund Avoin yhtiö | Wholesale & retail | 2007 |
| Kaiku Henkilöstöpalvelut Turku Oy | Administrative & support | 2014 |
| Kailo Oy | Wholesale & retail | 2022 |
| Kaimera Oy | Manufacturing | 2004 |
| Kaipuu & Kaiho avoin yhtiö | Arts & recreation | 2013 |
| Kairinen & Levo Oy | Professional & scientific | 2019 |
| Kairishuolto Oy | Administrative & support | 1979 |
| Kaitor Oy | Financial services | 2017 |
| Kaivon Liha Kaunismaa Oy | Wholesale & retail | 2010 |
| Kaivuri Turku Oy | Construction | 2019 |
| Kaivuuliike Kummala & Kumpp. Oy | Construction | 1975 |
| Kajahdus Oy | Information & communication | 2014 |
| Kajala Group Oy | Information & communication | 2007 |
| Kajander Capital Ab | Financial services | 2026 |
| Kajatus Oy | Health & social care | 2020 |
| Kajavalta Kapital Oy | Construction | 2004 |
| Kajo FM Oy | Professional & scientific | 2024 |
| KajoAI Oy | Information & communication | 2025 |
| Kajoè Oy | Other services | 2025 |
| Kakkukaksoset Avoin yhtiö | Manufacturing | 2018 |
| Kakkupuoti MariAnnika Oy | Manufacturing | 2023 |
| Kakola Brewing Company Oy | Manufacturing | 2017 |
| Kakola Invest Oy | Financial services | 2023 |
| Kakola SPA Oy | Other services | 2022 |
| Kakola Yhtiöt Oy | Real estate | 1989 |
| Kakolan Huolto Oy | Administrative & support | 2021 |
| Kakolan Rakennus Oy | Construction | 2017 |
| Kakolan Siivous Oy | Administrative & support | 2021 |
| Kakskerta-Satava vesiosuuskunta | Construction | 2007 |
| Kakskuus Kiinteistöt Oy | Real estate | 2023 |
| Kaksosten Grilli Ky | Hospitality | 1996 |
| KalKon Finance Oy | Professional & scientific | 2022 |
| Kalakukko Capital Oy | Real estate | 2020 |
| Kalaliike Fish Fellows Oy | Wholesale & retail | 2022 |
| Kalepro Oy | Construction | 2018 |
| Kalervo Tuonela Company Oy | Manufacturing | 2003 |
| Kaleva Invest Oy | Financial services | 2022 |
| Kalevan Kauppahuone Oy | Financial services | 1988 |
| Kallinen Consulting Oy | Administrative & support | 2014 |
| Kallio App Oy | Information & communication | 2018 |
| Kallioco Oy | Professional & scientific | 2023 |
| Kalliotasaus Oy | Construction | 2013 |
| Kalmari Invest Oy | Real estate | 2008 |
| Kalpalandia Oy | Professional & scientific | 2025 |
| Kalttas-Holding Oy | Real estate | 1978 |
| Kaluste-Sarokas Oy | Wholesale & retail | 1993 |
| Kalustetalo Savela Oy | Real estate | 2010 |
| Kalustetehdas Fineblo Oy | Manufacturing | 2009 |
| KalustoVahti Oy | Administrative & support | 2026 |
| Kalustomestarit Suomi Oy | Information & communication | 2012 |
| Kameleon Document Automation Oy | Information & communication | 2024 |
| Kamfix Oy | Manufacturing | 2018 |
| Kamika Oy | Information & communication | 1990 |
| Kamil Palvelutaksi Oy | Transport & logistics | 2022 |
| Kampaamo-Pesula Mikko Helin Oy | Other services | 2011 |
| Kampin Finanssi Oy | Wholesale & retail | 1992 |
| Kamu kalusteet Oy | Manufacturing | 2025 |
| Kane's Garage Oy | Other services | 2017 |
| Kanel Oy | Construction | 2025 |
| Kanerva Invest Oy | Financial services | 2007 |
| Kanesales Oy | Financial services | 2020 |
| Kanjako Oy | Construction | 1996 |
| Kansainvälistymisyritys Polku Oy | Wholesale & retail | 2021 |
| Kansallinen Terveyspalvelu Oy Testi | Health & social care | 1991 |
| Kansallis Konsultti Oy | Wholesale & retail | 1990 |
| Kansallis Oy | Financial services | 1997 |
| Kansallis-kehitys Oy | Real estate | 2013 |
| Kansallis-vuokra Oy | Real estate | 2021 |
| Kansallis-yhtiöt Oy | Real estate | 2019 |
| Kansankeittiö Oy | Hospitality | 2021 |
| Kantio Oy | Information & communication | 2009 |
| Kanto Asunnot Oy | Real estate | 2020 |
| Kantolan Porapaalutus Oy | Construction | 1995 |
| Kantolan Saaristokuljetus Oy | Construction | 1990 |
| Kantonen Consulting Oy | Financial services | 2022 |
| Kantsu-Palvelu Oy | Construction | 2020 |