| Jounin Klapi Oy | Agriculture & fishing | 2017 |
| JoutsenApu Oy | Health & social care | 2025 |
| Jr Rinne Oy | Wholesale & retail | 2000 |
| JuLe Oy | Financial services | 2023 |
| Juha Service Oy | Other services | 2021 |
| Juhani Karvo Oy | Real estate | 1997 |
| Juho Särkijärvi Consulting Oy | Manufacturing | 2019 |
| Jukka Honkanen Oy | Administrative & support | 2005 |
| Jukka Kursula ky | Construction | 1991 |
| Jukkolantien Parkettitalo Ky | Construction | 1987 |
| Julasa Oy | Real estate | 2013 |
| Julius Oförsagd Company Oy | Professional & scientific | 2014 |
| Junnujalmari Oy | Real estate | 2011 |
| Jussi Ylipieti Oy | Wholesale & retail | 1994 |
| Jussi-Pekka Koivisto Oy | Professional & scientific | 2019 |
| Justeeraus Oy | Information & communication | 2021 |
| Jutukas Oy | Health & social care | 2025 |
| Juujärvi Racing Oy | Construction | 2014 |
| Juurakonportti Oy | Hospitality | 2017 |
| Juuso Haarala Oy | Arts & recreation | 2024 |
| Juventas Ky | Administrative & support | 2006 |
| Jämytec Oy | Wholesale & retail | 1999 |
| Jänkäkettu Oy | Construction | 2024 |
| K. Ranta-Valkama Oy | Transport & logistics | 2016 |
| KAN Enterprise Oy | Hospitality | 2025 |
| KH Autotek Oy | Other services | 2025 |
| KHE service Oy | Manufacturing | 2021 |
| KIREE Oy | Other services | 2026 |
| Kivisalmi Consulting OY | Professional & scientific | 2024 |
| KJK Myynti Oy | Financial services | 2019 |
| KK Brodeeraus Oy | Manufacturing | 2018 |
| KK Horizon OY | Transport & logistics | 2025 |
| KK-Sähkötyöt Oy | Construction | 2023 |
| KM Putkityöt Oy | Construction | 2022 |
| KM-Projektikonsultointi Oy | Professional & scientific | 2018 |
| KMH-Yhtiöt Oy | Construction | 1994 |
| KMN Advisor Oy | Professional & scientific | 2013 |
| KO-KO-A tuotteet Oy | Manufacturing | 2020 |
| KOSKINIEMEN SÄHKÖ Ky | Construction | 2017 |
| KOY Kätkän Loisto | Real estate | 2026 |
| KP Finland Oy | Financial services | 2020 |
| KR Pientalot Ky | Construction | 1987 |
| KS Taksi Oy | Transport & logistics | 2024 |
| KSC Service Center Oy | Administrative & support | 2020 |
| KTS Sales Oy | Information & communication | 2026 |
| Kuusamon Lomakota Ky | Construction | 2003 |
| KaMi Lapland Oy | Hospitality | 2025 |
| Kaamos LVI Oy | Construction | 2026 |
| Kaaranneskosken Vesihuolto-osuuskunta | Water & waste | 2002 |
| Kaarihalli Oy | Manufacturing | 2008 |
| Kaartje Ky | Information & communication | 1991 |
| Kaavin MS-Kiinteistö Oy | Real estate | 2013 |
| Kahden Kokin Catering Oy | Hospitality | 2021 |
| Kahvi- ja Kakkuhetki Oy | Manufacturing | 2025 |
| Kahvila TITO Ky | Hospitality | 2006 |
| Kahvipiika Anne Springare Ky | Hospitality | 1991 |
| Kaihdin- ja Sisustus Teppo Kommandiittiyhtiö | Wholesale & retail | 1986 |
| Kaikor Oy | Wholesale & retail | 2015 |
| Kainuun lahja Oy | Financial services | 2023 |
| Kaira Brewing Company Oy | Manufacturing | 2021 |
| Kairala Taksipalvelut Oy | Transport & logistics | 2009 |
| Kairan Kuningatar Oy | Administrative & support | 2025 |
| Kairankulkija Oy | Professional & scientific | 1988 |
| Kairatallit Oy | Real estate | 1993 |
| Kaisto Creative Oy | Professional & scientific | 2025 |
| Kaiverrus Kallio Oy | Professional & scientific | 1989 |
| Kaivuriapu Oy | Construction | 2020 |
| Kaivuriapu Yhtiöt Oy | Administrative & support | 2021 |
| Kajo Holding Oy | Financial services | 2025 |
| Kalant Oy | Arts & recreation | 2003 |
| Kalotti-Tukku ky | Wholesale & retail | 1981 |
| Kalottiasennus Oy | Construction | 1998 |
| Kalottikone Oy | Manufacturing | 1997 |
| Kaltio Creative Oy | Professional & scientific | 2021 |
| Kaluste ALAVA Oy | Manufacturing | 2007 |
| Kaluste Varrio Oy | Wholesale & retail | 2011 |
| Kalusteasennus T Luusua Oy | Construction | 2023 |
| Kalustelinna Oy | Wholesale & retail | 2006 |
| Kamiri Oy | Hospitality | 2014 |
| Kammari Rovaniemi Oy | Hospitality | 2026 |
| Kampia Oy | Real estate | 2025 |
| Kanani Brothers Oy | Transport & logistics | 2024 |
| Kanava Hai Oy | Construction | 2016 |
| Kansainvälinen Lakiasiaintoimisto Morini&Kiikeri Ky | Professional & scientific | 2001 |
| Kanssa International Oy | Hospitality | 2018 |
| Kantia Oy | Professional & scientific | 2012 |
| Kanttikulma Oy | Administrative & support | 2023 |
| KapsaTek Oy | Financial services | 2020 |
| Karaokekeskus Invest Oy | Hospitality | 2011 |
| Karaokekeskus.com verkkokauppa Oy | Information & communication | 2004 |
| KarenGourmeeKala (KGK) Oy | Agriculture & fishing | 2013 |
| Kari Hoikka Oy | Real estate | 2004 |
| Kari Ylipulli Ky | Transport & logistics | 1999 |
| KariPR Ky | Real estate | 1989 |
| Kasi-Kiinteistöt Oy | Real estate | 1992 |
| Kassavahti Oy | Administrative & support | 2024 |
| Kasvuketju Oy | Education | 2020 |
| Kataja Innovations Oy | Professional & scientific | 2017 |
| Katastrofikorjaamo Oy | Other services | 2026 |
| KateFix Oy | Construction | 2014 |