| JMP Investments Oy | Arts & recreation | 2020 |
| JN-Konsultointi OY | Professional & scientific | 2016 |
| JOKPUU-Palvelut Oy | Agriculture & fishing | 2015 |
| JP-Kotiapu Oy | Health & social care | 2018 |
| JPuunkaadot Oy | Agriculture & fishing | 2023 |
| JS-Kaivin Oy | Construction | 2004 |
| JTK-works Oy | Construction | 2021 |
| JV Brewing oy | Manufacturing | 2018 |
| JVV Group Oy | Real estate | 2026 |
| Jaakko Juvonen Oy | Health & social care | 2022 |
| Jaakko Yrjölä Oy | Arts & recreation | 2020 |
| Jamito Oy | Manufacturing | 2013 |
| Jartom Oy | Construction | 1995 |
| Jaskan Auto ja Kone Ky | Other services | 1998 |
| JeTi-Tech Oy | Wholesale & retail | 2022 |
| Joko huolto Oy | Construction | 2024 |
| Jotus Oy | Professional & scientific | 2018 |
| Juju kosteusmittaus oy | Professional & scientific | 2022 |
| Julian Vaatekaappi avoin yhtiö | Wholesale & retail | 2006 |
| Julkisivumestarit Oy | Real estate | 2024 |
| Juoma-agentit Oy | Wholesale & retail | 1993 |
| Jupair Ky | Construction | 1985 |
| Jussin Ajoneuvopalvelu Oy | Other services | 2020 |
| K.N Trucks Oy | Wholesale & retail | 2020 |
| KMP Sähkö Oy | Construction | 2019 |
| KOY Pakaraisentie 35 | Real estate | 2018 |
| KWT-Tekniikka Oy | Construction | 2019 |
| Kaizen Institute Finland Oy | Professional & scientific | 2013 |
| Kaizen Institute Northern Europe Oy | Professional & scientific | 2024 |
| Kallio Race System Oy | Arts & recreation | 2009 |
| Kanoottiaika Oy | Wholesale & retail | 2003 |
| Kantarakentajat Oy | Construction | 2012 |
| Kaspernikki Oy | Administrative & support | 1995 |
| Kasvuko Oy | Professional & scientific | 2002 |
| Katekiinteistöt Oy | Real estate | 1989 |
| Kaukomieli Oy | Real estate | 1990 |
| Kauppahuone Tommi Mäkelä Oy | Wholesale & retail | 2002 |
| Kautar Oy | Professional & scientific | 1974 |
| Kebula Kokki Oy | Hospitality | 2022 |
| Kehityspolut Oy | Information & communication | 2002 |
| Kehitysvoima Oy | Professional & scientific | 2026 |
| Kehärohdos Oy | Wholesale & retail | 2010 |
| Kelloapu Oy | Wholesale & retail | 1995 |
| KenkäS Oy | Wholesale & retail | 2015 |
| Kerako Oy | Real estate | 1989 |
| Kerameija Oy | Professional & scientific | 2019 |
| Kerhis Oy | Arts & recreation | 1994 |
| Keski-Hämeen Rakennus Oy | Construction | 1994 |
| Keskin Ateria Oy | Hospitality | 2020 |
| Kesäpihan Puutarha Oy | Agriculture & fishing | 2014 |
| Kevytrahti Merioksa & Nieminen Oy | Transport & logistics | 1994 |
| Kiinteistö Oy Horsmankulma | Real estate | 1989 |
| Kiinteistö Oy Huoltoasema Hahl | Real estate | 1994 |
| Kiinteistö Oy Kauppaneuvos | Real estate | 2014 |
| Kiinteistö Oy Kärki-Himos | Real estate | 2007 |
| Kiinteistö Oy Levin Teerenpesä | Hospitality | 1999 |
| Kiinteistö Oy Valkeakosken Lotilantie 49 | Real estate | 2017 |
| Kiinteistö Oy Valkeakosken Maijankoski | Real estate | 1991 |
| Kiinteistö Oy Valkeakosken Mottitie 5 | Real estate | 1985 |
| Kiinteistö Oy Valkeakosken Peuranoronkatu 6 | Real estate | 2019 |
| Kiinteistö Oy Valkeakosken Salonkadun Eemeli | Real estate | 2002 |
| Kiinteistö Oy Valkeakosken Sammonkatu 21 | Real estate | 2001 |
| Kiinteistö Oy Valtakatu 31 Valkeakoski | Real estate | 2001 |
| Kiinteistö Oy Vanhakylä | Real estate | 2016 |
| Kiinteistö Oy Viialan Teponkuja 3 | Real estate | 1980 |
| Kiinteistöosakeyhtiö Valkeakosken Huhtakatu 2 | Real estate | 2019 |
| Kimmo Piiroinen Oy | Health & social care | 2003 |
| Kirjansuunnittelu Korpus Oy | Manufacturing | 1995 |
| Kirjaskadun Huoltoasema Oy | Wholesale & retail | 2015 |
| Kirjaskadun rakennus oy | Real estate | 2021 |
| Kodikkaat Oy | Real estate | 2024 |
| Koillisen Tamarex Oy | Construction | 2006 |
| Koitto Partners Oy | Financial services | 2026 |
| KoneApaja Oy | Manufacturing | 2008 |
| Konsilo Oy | Professional & scientific | 2008 |
| Konsultointi UoVi Oy | Professional & scientific | 2017 |
| Koodimies Konsultointi Oy | Information & communication | 2023 |
| Koodit ja Koneet Oy | Information & communication | 2010 |
| Korentis Oy | Professional & scientific | 2026 |
| Korkeakankaan Ratsutila Oy | Real estate | 2018 |
| Kosken Kajo Oy | Other services | 2025 |
| Koski Padel Oy | Arts & recreation | 2018 |
| Koski-Kolmio Oy | Wholesale & retail | 2008 |
| Koskiauto Oy | Wholesale & retail | 2021 |
| Koskijaloste Oy | Wholesale & retail | 2018 |
| Koskikylpy Oy | Administrative & support | 2013 |
| Koskilattiat Oy | Construction | 2003 |
| Koskin Autofix oy | Other services | 2026 |
| Koskin Automyynti Oy | Wholesale & retail | 1985 |
| Koskin Hammas Oy | Manufacturing | 2011 |
| Koskin Import Oy | Wholesale & retail | 2014 |
| Koskin Kurotus ja Kuljetus Oy | Transport & logistics | 2013 |
| Koskin Prässituote Oy | Manufacturing | 2021 |
| Koskin Rengaspiste Oy | Wholesale & retail | 2009 |
| Koskin Teräsmyynti Oy | Wholesale & retail | 1989 |
| Koskin maalauspalvelu Oy | Construction | 1995 |
| Koskin maanrakennus ja purku Oy | Construction | 1993 |
| Koskioptiikka Ky | Wholesale & retail | 1990 |
| Koskiprässi Oy | Manufacturing | 2012 |
| Koti Koskissa Oy | Real estate | 2011 |