| Kitsas Oy | Information & communication | 2019 |
| Koeda Consulting Oy | Information & communication | 2022 |
| Kouvolan City Rent huolto ja tarvike Oy | Administrative & support | 1995 |
| Kouvolan City-Sisustajat Oy | Wholesale & retail | 1989 |
| Kouvolan Fysiatripalvelut Oy | Health & social care | 2024 |
| Kouvolan LVI-Palvelu Oy | Construction | 2017 |
| Kouvolan Ruokaostos Suikkanen Oy | Wholesale & retail | 1980 |
| Kovaoksa Oy | Agriculture & fishing | 2016 |
| Kuljetus M. Rossi Ky | Transport & logistics | 2014 |
| Kuljetus M. Vainikka Oy | Transport & logistics | 2015 |
| Kuljetus Muuronen Oy | Transport & logistics | 2001 |
| Kuljetus Ruuth Ky | Transport & logistics | 2014 |
| Kuljetus T Eklund Oy | Transport & logistics | 2005 |
| Kuljetus T.Kylliäinen Oy | Transport & logistics | 1999 |
| Kuljetus Toni Niemi Oy | Transport & logistics | 2011 |
| Kuljetus Väänänen Oy | Transport & logistics | 2019 |
| Kuljetusliike Seppo J. Lehtinen kommandiittiyhtiö | Transport & logistics | 1974 |
| Kymagro Group Oy | Wholesale & retail | 2023 |
| Kymagro Oy | Wholesale & retail | 2016 |
| Kymen IV-Valmistus Oy | Manufacturing | 2014 |
| Kymen Koneenrakennus Oy | Manufacturing | 2014 |
| Kymen Lakiasiaintoimisto Oy | Professional & scientific | 1989 |
| Kymen Lämpöpalvelu Oy | Construction | 2018 |
| Kymen Oivakoti Oy | Health & social care | 1998 |
| Kymen Putkipojat Oy | Construction | 2003 |
| Kymen Puukiipijä Oy | Agriculture & fishing | 2025 |
| Kymen Septech Oy | Wholesale & retail | 2001 |
| Kymenkosken Kiinteistö Oy | Real estate | 2014 |
| L&R Medical Oy | Health & social care | 2022 |
| LT Engineering Oy | Manufacturing | 2022 |
| Laiho Projektit Oy | Construction | 2025 |
| Lappeenrannan Aluslava Oy | Manufacturing | 2023 |
| Lasipack Oy | Construction | 1980 |
| Laukkanen Forest Ky | Agriculture & fishing | 1986 |
| Lehmuskoti Invest & Holding Oy | Real estate | 2023 |
| Lehtis Oy | Health & social care | 2020 |
| Leipomo Koppanen Ky | Manufacturing | 1981 |
| Lennison Oy | Arts & recreation | 2000 |
| Linja-autoliikenne P. Puolakka Ky | Transport & logistics | 1980 |
| Lohikukko Oy | Hospitality | 2026 |
| Lounas- ja pitopalvelu Iltatähti Oy | Hospitality | 2020 |
| Lucanvest Oy | Financial services | 2013 |
| Lukasson Oy | Professional & scientific | 1982 |
| Lähdepelto Oy | Construction | 2008 |
| M.D Palanne Oy | Health & social care | 2012 |
| ML MultiService Oy | Professional & scientific | 2026 |
| Maames Oy | Wholesale & retail | 2024 |
| Maanrakennus A. Putkinen Oy | Construction | 2007 |
| Maanrakennus Kanervo Oy | Mining & quarrying | 1987 |
| Maansiirto L & A Oy | Construction | 2001 |
| Mankki Holding Oy | Financial services | 2022 |
| Markkinointisuunnittelu Kylliäinen Oy | Professional & scientific | 1993 |
| Mart-invest oy | Real estate | 2019 |
| Maxbar oy | Hospitality | 2024 |
| Metallityöliike Mert Kommandiittiyhtiö | Manufacturing | 1990 |
| Metsäenergia ja -palvelu J & V Simola avoin yhtiö | Agriculture & fishing | 2006 |
| Mittakolmio Ky | Professional & scientific | 2007 |
| Monikaivu ja Rakenne Velj. Töyrylä Oy | Transport & logistics | 1979 |
| Mutelog Oy | Professional & scientific | 2019 |
| Nappa Group Oy | Real estate | 2021 |
| Nappa Machine Oy | Other services | 2013 |
| Nekanvaaja Oy | Health & social care | 2022 |
| Never Enough Ky | Arts & recreation | 2008 |
| Niemenmaan vesihuolto-osuuskunta | Water & waste | 2004 |
| Nomel Oy | Financial services | 2005 |
| Nord Lommerse Flower Bulb Group Oy | Wholesale & retail | 2003 |
| Norppa-Laiturit Oy | Wholesale & retail | 1998 |
| Nostalgialeidit avoin yhtiö | Hospitality | 2013 |
| Nostetec Oy | Administrative & support | 2019 |
| Nosto ja Kuljetus S. Lehtinen Oy | Transport & logistics | 2006 |
| Nuohoustoimi Seppälä Ky | Administrative & support | 2019 |
| Näkkimistön Maito Oy | Agriculture & fishing | 2012 |
| OPVH Oy | Health & social care | 2024 |
| Onnellinen Urho Oy | Financial services | 2026 |
| Orpe Kuljetus Oy | Transport & logistics | 1984 |
| Oy Danels Ab | Wholesale & retail | 1998 |
| Plusvire OY | Health & social care | 2011 |
| PP-Valvonta Oy | Professional & scientific | 1998 |
| PSS Keino Oy | Hospitality | 2007 |
| Papa Racing avoin yhtiö | Arts & recreation | 2005 |
| Pavillo Oy | Arts & recreation | 2004 |
| Peltola Holding Oy | Financial services | 2022 |
| Pepe Unlimited Oy | Information & communication | 2018 |
| Pienenpieni Farmi Oy | Agriculture & fishing | 2025 |
| PiipunWarjo Oy | Financial services | 2016 |
| Pinenta Oy | Manufacturing | 2008 |
| Pitomestarit Aarno Anttila Oy | Hospitality | 1990 |
| Proexe Oy | Professional & scientific | 2025 |
| Prosum Oy | Professional & scientific | 2019 |
| Puutuote Matti Papu Ky | Manufacturing | 1991 |
| Puzzle Sport Oy | Education | 2019 |
| Rpjt Valkeala OY | Wholesale & retail | 2019 |
| RS Workers Oy | Manufacturing | 2023 |
| RailSafe Finland Oy | Construction | 2021 |
| Rajput Group Oy | Hospitality | 2019 |
| Rakennus K. Rantala Oy | Construction | 1974 |
| Rakennus Maveter Oy | Construction | 2002 |
| Rakennusapu P. Heino Oy | Construction | 2006 |
| Rakennusedustus Olapuu Ky | Construction | 1985 |
| Rakennusliike P Rämä Ky | Construction | 2001 |