| Kaikkea on Oy | Other services | 2023 |
| Kajala Kiinteistöt Oy | Real estate | 2021 |
| Kaketeko Oy | Professional & scientific | 2015 |
| Kakluuni Restaurointi Oravainen Oy | Construction | 1989 |
| Kaks Lohi Oy | Real estate | 1987 |
| Kalaliike J Salmela Ky | Wholesale & retail | 1990 |
| Kalokero Oy | Real estate | 1994 |
| Kanplan Oy | Professional & scientific | 2010 |
| Kantojoen Loma Oy | Real estate | 1992 |
| Kapida Oy | Professional & scientific | 2010 |
| Karawatski Engineering Oy | Professional & scientific | 2001 |
| Karawatski Oy | Professional & scientific | 1989 |
| Karhulan Kumihuolto Ky | Professional & scientific | 1967 |
| Karni Oy | Health & social care | 2021 |
| Kartanokaivos Oy | Real estate | 2025 |
| Katakapital Oy | Real estate | 2009 |
| Katsastus 10 Oy | Professional & scientific | 2016 |
| Kattelmäki Palvelut Oy | Transport & logistics | 2021 |
| Kaukomeri Oy | Manufacturing | 1972 |
| Kaune Oy | Manufacturing | 1996 |
| Kauneudentaikoja oy | Other services | 2020 |
| Kauppahuone Joremi Oy | Administrative & support | 1999 |
| Kauppatorin Röntgen Ky | Health & social care | 1973 |
| Kekked Oy | Information & communication | 2018 |
| Kelapojat Oy | Water & waste | 2024 |
| Kelposepät oy | Construction | 2018 |
| Keresi Oy | Hospitality | 2014 |
| Kettunen-Invest Oy | Financial services | 1988 |
| Kiint Oy Naantalin Katinhäntä | Real estate | 1981 |
| Kiinteistö Oy Allastie 8 | Real estate | 1996 |
| Kiinteistö Oy Aurinkotie | Real estate | 1982 |
| Kiinteistö Oy Juoksijanpuisto | Real estate | 2008 |
| Kiinteistö Oy Kaanaanlinna | Real estate | 1989 |
| Kiinteistö Oy Keräilylinna | Real estate | 2016 |
| Kiinteistö Oy Kuninkojan Laakso | Real estate | 2006 |
| Kiinteistö Oy Lietsalan Liiketalo | Real estate | 1993 |
| Kiinteistö Oy Lisenssikatu | Real estate | 2004 |
| Kiinteistö Oy Lännentupa | Real estate | 1985 |
| Kiinteistö Oy Naantalin Kaivokatu 21 | Real estate | 2001 |
| Kiinteistö Oy Naantalin Kupariranta | Real estate | 2024 |
| Kiinteistö Oy Naantalin Linkki | Real estate | 2007 |
| Kiinteistö Oy Naantalin Lisenssi | Real estate | 2007 |
| Kiinteistö Oy Naantalin Patenttihalli | Real estate | 2001 |
| Kiinteistö Oy Naantalin Penkka | Real estate | 2005 |
| Kiinteistö Oy Naantalin Rantakatu 4 | Real estate | 1982 |
| Kiinteistö Oy Naantalin Rautakatu 1 | Real estate | 1982 |
| Kiinteistö Oy Naantalin Teollisuusvisio | Real estate | 1991 |
| Kiinteistö Oy Naantalin suojatyökeskus | Real estate | 1984 |
| Kiinteistö Oy Porin Kesämaa | Real estate | 1992 |
| Kiinteistö Oy Pyölin Kivinavetta | Real estate | 2011 |
| Kiinteistö Oy Raision Sammalkallionkatu 9 | Real estate | 2023 |
| Kiinteistö Oy Ruskon MP-talo | Real estate | 1984 |
| Kiinteistö Oy Ruskontie 2 | Real estate | 2020 |
| Kiinteistö Oy Trapinranta | Real estate | 2010 |
| Kiinteistö Oy Viialanranta | Real estate | 1960 |
| Kiinteistö Oy Yläneen Koli | Real estate | 1991 |
| Kiinteistömoguli Oy | Real estate | 2013 |
| Kiinteistöosakeyhtiö Tiemestarinkatu 3, Turku | Real estate | 2012 |
| Kiinteistöosakeyhtiö Veljekset Aaltonen | Real estate | 2020 |
| Kiinteistöyhtiö Jussit Oy | Real estate | 2004 |
| Kimmo Helle Sport Trading Oy | Wholesale & retail | 2013 |
| Kimppupiste Oy | Wholesale & retail | 2024 |
| Kirsikka purkki Oy | Real estate | 2023 |
| Kiviranta Group Oy | Professional & scientific | 2010 |
| Kiwine Oy | Wholesale & retail | 2025 |
| Kokari Oy | Other services | 2021 |
| Kommunikointipalvelut Kuuluville Oy | Professional & scientific | 2013 |
| Konsultointi Turku Fine Oy | Professional & scientific | 2020 |
| Koolinki Oy | Construction | 2013 |
| Korpikallio Oy | Real estate | 2026 |
| KotiPito Oy | Construction | 2025 |
| Kravion Oy | Construction | 2019 |
| Kristian & Aleksander Oy | Wholesale & retail | 2022 |
| Krivest Yard Oy | Manufacturing | 2018 |
| Kudomo Oy | Wholesale & retail | 2022 |
| Kukko & Koukku Oy | Hospitality | 2020 |
| Kuljetus A Luukko Oy | Transport & logistics | 2019 |
| Kuljetus J Tapiola Oy | Other services | 2021 |
| Kultapossut Oy | Hospitality | 2021 |
| Kultarannan Kivi Oy | Other services | 2016 |
| Kultarannan Laki ja Kiinteistö Oy | Professional & scientific | 2015 |
| Kultaranta Green Village Oy | Real estate | 2021 |
| Kultaranta Invest Oy | Real estate | 1989 |
| Kultaranta Marina A & B Oy | Arts & recreation | 2012 |
| Kultaranta Marina C Oy | Transport & logistics | 2015 |
| Kultaranta Resort Oy | Arts & recreation | 2006 |
| Kultareunus Oy | Health & social care | 2025 |
| Kuntotalli Naantali Oy | Arts & recreation | 2025 |
| Kuutuki Oy | Professional & scientific | 2025 |
| Kymppi-Katto Oy | Professional & scientific | 2022 |
| LKV Himanen Oy | Real estate | 2018 |
| LKV Organization Brand Oy | Professional & scientific | 2024 |
| LKV Tuomiset Oy | Real estate | 2012 |
| LL-Asennus Oy | Construction | 2002 |
| LMV-Cleaning Oy | Administrative & support | 2007 |
| LS-Motors Oy | Other services | 2023 |
| LTK Med Oy | Health & social care | 2024 |
| LVI-Flex Oy | Construction | 2017 |
| LVI-Nummelin oy | Construction | 2022 |
| LVI-suunnittelu Laaksonen Oy | Professional & scientific | 2007 |