| Ilanois Oy | Financial services | 2022 |
| Ilomäki Consulting Oy | Professional & scientific | 2021 |
| Insinööritoimisto Haapamäki Oy | Construction | 2003 |
| Insinööriverstas Oy | Professional & scientific | 2020 |
| Inspiration Group Oy | Professional & scientific | 2011 |
| Investle Oy | Financial services | 2021 |
| J&K Safety Oy | Administrative & support | 2020 |
| J. Vehniä Ky | Transport & logistics | 2004 |
| JK-Provide Oy | Manufacturing | 2002 |
| JKN Motors Oy | Other services | 2025 |
| JM-NMT-Palvelu Ky | Wholesale & retail | 1992 |
| JSI Invest Oy | Real estate | 2021 |
| JVR-Soft Oy | Information & communication | 1995 |
| JY Terveys Oy | Health & social care | 2021 |
| Jalavo Invest Oy | Other services | 1999 |
| Jaskari Rakennus Oy | Construction | 2004 |
| Jaskari Yhtiöt Oy | Real estate | 2004 |
| Jii-Tee Sport Oy | Wholesale & retail | 2007 |
| JiiVee Solutions Oy | Arts & recreation | 1987 |
| Jollman Consulting Oy | Professional & scientific | 2022 |
| Joy & Fire Partners Oy | Real estate | 2025 |
| Jussila Sijoitus Oy | Wholesale & retail | 2025 |
| JxP Palvelut Oy | Administrative & support | 2010 |
| Jymy SB Oy | Arts & recreation | 2026 |
| Jyväskylän Tavaralähetit Oy | Transport & logistics | 2015 |
| Kaunis Suu OY | Health & social care | 2011 |
| KLJ Rakennuspalvelu Oy | Construction | 2023 |
| KONEITA Kiinteistöt Oy | Real estate | 2021 |
| KOVAT Company Oy | Administrative & support | 2023 |
| Kahden Kosken palvelut Oy | Education | 2025 |
| Kaikua oy | Health & social care | 2018 |
| Karjalainen Yhtiöt Oy | Information & communication | 2021 |
| Karon Consulting Oy | Wholesale & retail | 2012 |
| Kasey Corporation Oy | Information & communication | 2007 |
| Kasiturkis Oy | Agriculture & fishing | 2015 |
| Kasvunmaailma Oy | Financial services | 2017 |
| Kattoyksikkö Oy | Construction | 2020 |
| Kauneushoitola Anne Pakkanen Ky | Other services | 1998 |
| Kaunis Hymy Oy | Health & social care | 2024 |
| Kehitysyhtiö Interwendos Oy | Construction | 1994 |
| Keinopiste Oy | Professional & scientific | 2019 |
| Ketola Clean Ky | Wholesale & retail | 2007 |
| Ketola Holding Oy | Professional & scientific | 2017 |
| Kiinteistö Oy Antiikkitalo | Real estate | 1989 |
| Kiinteistö Oy Kaarankulma | Real estate | 1989 |
| Kiinteistö Oy Kajuma | Real estate | 2008 |
| Kiinteistö Oy Kiito | Real estate | 2025 |
| Kiinteistö Oy Lomapeltru | Real estate | 2002 |
| Kiinteistö Oy Näpertäjäntie 3 | Real estate | 2011 |
| Kiinteistö Oy Oivaltajantie 3 | Real estate | 2011 |
| Kiinteistö Oy Rukanenä | Real estate | 1990 |
| Kiinteistö Oy Rukaposki | Real estate | 1990 |
| Kiinteistö Oy Seinäjoen Pelttarinkatu 6 B | Real estate | 1992 |
| Kiinteistö Oy Seinäjoen Runkotie 16 | Real estate | 2011 |
| Kiinteistö Oy Sorvitie | Real estate | 2014 |
| Kiinteistömaakarit Oy | Financial services | 2011 |
| Kinestetiikka Seppo Hauta Oy | Education | 2017 |
| Konehuolto Antti Kalliokoski Ky | Manufacturing | 1991 |
| Konehuolto P. Saranpää Oy | Manufacturing | 2011 |
| Konepalvelu Tattari Oy | Agriculture & fishing | 2026 |
| Kosti Saukko Oy | Transport & logistics | 2001 |
| KosuCon Oy | Construction | 2022 |
| Koti-Kari Oy | Real estate | 1999 |
| Kouran Kiinteistö Oy | Real estate | 1992 |
| Kristallilinja Oy | Wholesale & retail | 2009 |
| Kuljetus A. Korkeamäki Oy | Transport & logistics | 1994 |
| Kuljetus H.Ketola Oy | Transport & logistics | 2009 |
| Kuljetus Riepponen Oy | Transport & logistics | 2020 |
| Kuljetusliike Mauno Mäki Oy | Transport & logistics | 2003 |
| Kuljetusliike Nummijoki Oy | Transport & logistics | 1995 |
| Kuljetusliike Saarela Ky | Transport & logistics | 2011 |
| Kurjenkytö Oy | Agriculture & fishing | 2021 |
| Kytösavu Osakeyhtiö | Administrative & support | 1938 |
| L. Suomela Oy | Transport & logistics | 2013 |
| LA kiinteistöt Oy | Real estate | 2019 |
| Lrkt Pohjanmaa OY | Real estate | 2018 |
| LS Paino Ky | Manufacturing | 2015 |
| LaatuSaumarit Oy | Construction | 2021 |
| Labrum Estates Oy | Real estate | 2024 |
| Labrum Oy | Health & social care | 2009 |
| Laitemyynti Välikangas Ky | Wholesale & retail | 2013 |
| Lajina Mieli Oy | Professional & scientific | 2020 |
| Lakee music Oy | Information & communication | 2025 |
| Lakeuden Agrihuolto Ky | Manufacturing | 1992 |
| Lakeuden Fysiopiste Ky | Health & social care | 2001 |
| Lakeuden Isännöinti Oy | Real estate | 1989 |
| Lakeuden KotiAvustajat Oy | Health & social care | 2011 |
| Lakeuden Laude Oy | Manufacturing | 2022 |
| Lakeuden Rakennuttajapalvelut Oy | Professional & scientific | 2016 |
| Lakeuden Ravitsemusterapia Oy | Health & social care | 2019 |
| Lakeuden Sprinkleri Oy | Construction | 2017 |
| Lakeuden Timanttiporaus Oy | Construction | 2024 |
| Lakeuden Vakuutuspojat Oy | Financial services | 2013 |
| Lakeus Cars Oy | Wholesale & retail | 2022 |
| Lakeus Hotels Oy | Hospitality | 2023 |
| Lakeus Wake Oy | Arts & recreation | 2017 |
| LakiLinja Oy | Professional & scientific | 2024 |
| Lakipalvelut Annala Oy | Professional & scientific | 2023 |
| Lape-Lastaus Oy | Agriculture & fishing | 1994 |
| Lappajärven kesäteatteri Oy | Arts & recreation | 2017 |