| Klettenberg Oy | Construction | 2022 |
| Klintens kontors- och industrifastigheter Ab | Real estate | 2013 |
| Klubiravintola Vaara Oy | Hospitality | 2023 |
| Knappens Ab | Financial services | 2022 |
| Knox Group Oy | Construction | 2015 |
| Koala Media Oy | Professional & scientific | 2022 |
| Kodin Laatutavara Oy | Wholesale & retail | 2020 |
| KodinNet Oy | Construction | 2022 |
| Kodit Deep Blue GP Oy | Financial services | 2020 |
| Kodit GP 1 Finland Oy | Financial services | 2019 |
| Kohdetrio Oy | Real estate | 2023 |
| Kohenen Oy | Hospitality | 2020 |
| Koillis-Savon Hirsirakenne Ky | Manufacturing | 1993 |
| Koillis-Savon Kuljetus Oy | Transport & logistics | 2020 |
| Koillisen Darem Oy | Hospitality | 2016 |
| Koillisen Negomex Oy | Arts & recreation | 2020 |
| Koivumäki & Co Oy LKV | Real estate | 2019 |
| Kokara oy | Hospitality | 2021 |
| Kokkolan AL Auto Oy | Wholesale & retail | 2021 |
| Kokkolan Caravan Huolto J.Autio Ky | Other services | 2001 |
| Kolarikorjaamo Toom Oy | Other services | 2019 |
| Kolmosrakenne Oy | Real estate | 2007 |
| Komapro Oy | Manufacturing | 2021 |
| KonaMafia Oy | Real estate | 2019 |
| Konditorio-Kahvila Mäkynen & Tapio KY | Hospitality | 1989 |
| Kone Auto Koskinen Ky | | 1982 |
| Kone Jalmari OY | Construction | 2020 |
| Koneet seisoo Oy | Wholesale & retail | 2020 |
| Koneinfra Oy | Administrative & support | 2015 |
| Konepaja Sitikov Oy | Manufacturing | 2021 |
| Konepaja Tirronen Oy | Manufacturing | 2021 |
| Konepalvelu R. Aho Oy | Other services | 2016 |
| Konepalvelu Rautakorpi Oy | Construction | 2003 |
| Konepalvelu T Viita-aho Ky | Wholesale & retail | 1971 |
| Konesalo OY | Wholesale & retail | 2021 |
| Koneurakointi FMJ Oy | Construction | 2020 |
| Koneurakointi Matti Tuokko Oy | Construction | 1996 |
| Koniju oy | Hospitality | 2022 |
| Konsora Oy | Other services | 2024 |
| Konsultointi ja viestintä Nikola Oy | Professional & scientific | 2010 |
| Konsulttikympit Oy | Professional & scientific | 2022 |
| Kontula24 Oy | Other services | 2021 |
| KooÄr Oy | Construction | 2019 |
| Korjaamo Autotoveri Oy | Other services | 2020 |
| Korka-Ravintola Oy | Hospitality | 2018 |
| Korkeavuoren Antiikki Oy | Wholesale & retail | 2001 |
| Korpikylän Vesiosuuskunta | Water & waste | 1950 |
| Korson yötupa oy | Hospitality | 2025 |
| Koseli Oy | Hospitality | 2017 |
| Koskinen Entertainment Oy | Arts & recreation | 2022 |
| Koskisen Serkukset Oy | Real estate | 1993 |
| Kostamo Medical Consulting Oy | Health & social care | 2021 |
| Kotapuro Oy | Administrative & support | 2022 |
| Koteshwor Oy | Hospitality | 2018 |
| Koti Pohjoinen Pitkä Oy | Real estate | 2024 |
| Koti Pohjoinen Taattu Oy | Real estate | 2024 |
| KotiNopeasti Oy | Real estate | 2021 |
| Kotikeittiömestarit Oy | Wholesale & retail | 2009 |
| Kotikomero Oy | Other services | 2022 |
| Kotilääkäri Liinamaa Oy | Administrative & support | 2023 |
| Kotimaan Valoenergia Oy | Administrative & support | 2020 |
| Kotipilari Oy | Construction | 1993 |
| Kotisairaala03 Oy | Health & social care | 2020 |
| Koto Group Oy | Hospitality | 2024 |
| Kouvolan Kauneus- ja terveyskeidas Ky | Other services | 1987 |
| Kova Ote Oy | Financial services | 2022 |
| Kovolli Oy | Information & communication | 2019 |
| Koy varasto-osake Kivikonlaita 34 | Real estate | 2017 |
| Kraft Co Oy | Wholesale & retail | 2009 |
| Kreto oy | Construction | 2020 |
| Krisp Foods Oy | Wholesale & retail | 2022 |
| Kroppasi.fi Oy | Wholesale & retail | 2022 |
| Krossi Invest Oy Ab | Real estate | 2021 |
| KuanChain Oy | Information & communication | 2017 |
| Kuffi Oy | Wholesale & retail | 2014 |
| Kuhistoni Capital Oy | Transport & logistics | 2020 |
| Kuhmon Pizzeria Oy | Hospitality | 2020 |
| Kuka Helsinki Oy | Information & communication | 2015 |
| Kukaekario Oy | Other services | 2020 |
| Kukista kaikki Oy | Wholesale & retail | 2023 |
| Kulend Oy | Construction | 2007 |
| Kuljettajasi Fleet Oy | Transport & logistics | 1996 |
| Kuljetus 189 Oy | Transport & logistics | 2017 |
| Kuljetus A. Saarela Oy | Transport & logistics | 2024 |
| Kuljetus Heikki Mahlamäki Ky | Transport & logistics | 2019 |
| Kuljetus JTiihone Oy | Transport & logistics | 2012 |
| Kuljetus Katila Oy | Transport & logistics | 2016 |
| Kuljetus ja Saneeraus Huikko Oy | Construction | 2023 |
| Kuljetusliike Mika Vasava Oy | Administrative & support | 2021 |
| Kuljetusliike Rauhala Oy | Transport & logistics | 1992 |
| Kuljetuspalvelu J Mustonen Oy | Transport & logistics | 2022 |
| Kuljetuspalvelu Pikku Kokko Oy | Transport & logistics | 2015 |
| Kulta Katto Oy | Construction | 2019 |
| Kulta Saimaa Oy | Construction | 2021 |
| Kultainen Rea-Palvelu Oy | Administrative & support | 2008 |
| Kultalinja Oy | Administrative & support | 2021 |
| Kulttuuriosuuskunta Sähinä | Arts & recreation | 2015 |
| Kuniko Finland Oy | Mining & quarrying | 2023 |
| Kunnon Ote Oy | Other services | 2017 |
| Kunnossapito Service Oy | Construction | 2022 |