| 9R Group Oy | Administrative & support | 2025 |
| AT mini-woods Ky | Agriculture & fishing | 2012 |
| Aresoil Oy | Real estate | 1995 |
| ArsMondo Oy | Arts & recreation | 2010 |
| Artefer Finland Oy | Manufacturing | 2005 |
| Arvix Oy | Other services | 2025 |
| Arvolista Oy | Manufacturing | 1994 |
| Autolafka Oy | Wholesale & retail | 2026 |
| Automaatiopalvelu A. Väistö Oy | Construction | 1992 |
| Chemes Ky | Wholesale & retail | 2005 |
| Das kieli- ja suunnittelutoimisto Ky | Professional & scientific | 1999 |
| E Poikala-Palvelut Oy | Construction | 1999 |
| ET Automotive Solutions Oy | Professional & scientific | 2008 |
| ET Contact Oy | Professional & scientific | 2025 |
| Eastsec Oy | Administrative & support | 2007 |
| Erik Sinisalo Putki Ky | | 1987 |
| Femola Oy | Construction | 1997 |
| FiSeOu Oy | Administrative & support | 2016 |
| Focus-Tuotanto Oy | Manufacturing | 2011 |
| Grafita Palvelut Oy | Information & communication | 2020 |
| HS-markkinointi Oy | Manufacturing | 2000 |
| Heavy Assistance Oy | Professional & scientific | 2019 |
| Hospes Finland Oy | Real estate | 2024 |
| Häkkinen Works Oy | Professional & scientific | 2026 |
| Industrial Bonding Oy | Wholesale & retail | 2018 |
| Instrumenttiasennus ja -huolto Ky A. Väistö | | 1975 |
| JR. Kuiri Ky | Construction | 2017 |
| JT Maatalous Oy | Agriculture & fishing | 2004 |
| JTM-Infra Oy | Construction | 2024 |
| JawaTalli Oy | Wholesale & retail | 2013 |
| Jokeriasunnot Oy | Real estate | 2024 |
| Jäsperic Oy | Construction | 2015 |
| KK-Kiinteistöpalvelu Oy | Administrative & support | 2011 |
| Kaakon laatuvälitys Oy | Real estate | 2021 |
| Kannos Creatives Oy | Professional & scientific | 2021 |
| Keroil Oy | Wholesale & retail | 2003 |
| Kiinteistö Oy Myllykosken Koulupolku 1 | Real estate | 2024 |
| Kiviniemi & Malkki Oy | Professional & scientific | 2013 |
| Kodinremontit Laine&Suolanen Oy | Construction | 2017 |
| Koje Oy | Professional & scientific | 2024 |
| KomuTallit Oy | Real estate | 2025 |
| Komujärvi Oy | Manufacturing | 2016 |
| Koodifarmi Oy | Information & communication | 2016 |
| Korpela Group Oy | Construction | 1992 |
| Kouvolan Hotellikiinteistö Oy | Real estate | 1969 |
| Kouvolan Jäätelö Oy | Wholesale & retail | 2010 |
| Kouvolan Psykoterapia Oy | Health & social care | 2023 |
| Kouvolan Sun-Filter Oy | Transport & logistics | 1994 |
| Kuljetus ja Maansiirto Hirvonen Ky | Transport & logistics | 2010 |
| Kuljetusliike Arposalo Oy | Transport & logistics | 1984 |
| Kulttuuritalo Wanha Rautakauppa Oy | Real estate | 2018 |
| Kumi-Tarvike Esko Nenonen Ky | Wholesale & retail | 1987 |
| Kuntosali GeBy Oy | Arts & recreation | 2022 |
| Kurittu Invest Oy | Financial services | 2014 |
| Ky A. Lehto, vastuunalaiset Pulli ja Olsson | Wholesale & retail | 1966 |
| Kymen Kuormalava ky | Wholesale & retail | 2012 |
| Kymen Peltirakenne Oy | Construction | 1986 |
| Kymen Polttoöljymyynti Oy | Wholesale & retail | 1984 |
| Kymen Purku ja Asbestityö Oy | Construction | 2023 |
| Kymen osto- ja myyntipalvelu Oy | Wholesale & retail | 2019 |
| Kymenlaakson maalaus- ja kiinteistöhuolto Oy | Construction | 2025 |
| LP Support Service Oy | Administrative & support | 2019 |
| Lakiasiat Pertti Manninen Oy | Professional & scientific | 1989 |
| Liikenne Valtonen Oy | Transport & logistics | 2007 |
| Lisäpalvelu Itä-Suomi Oy | Administrative & support | 2022 |
| Lisäpato Consulting Oy | Professional & scientific | 2023 |
| Lisäpato Oy | Professional & scientific | 2007 |
| Logcoy Oy Ltd | Transport & logistics | 2001 |
| Lohikäärmeen Luola Oy | Wholesale & retail | 2022 |
| Louhintatyö Immonen Oy | Mining & quarrying | 2021 |
| Lukkarin Maatila Oy | Agriculture & fishing | 2012 |
| Luoto Homes Finland Oy | Administrative & support | 2024 |
| Luoto Homes Helsinki Oy | Administrative & support | 2023 |
| Luoto Homes Oy | Real estate | 2024 |
| Lääkäripäivystys Hokkanen Ky | Health & social care | 2003 |
| MPMania Oy | Wholesale & retail | 2020 |
| Madamet Oy | Administrative & support | 2024 |
| Makeesa oy | Construction | 2024 |
| Metsä ja Kone Kujala oy | Agriculture & fishing | 2023 |
| Miilu-Veneet Oy | Manufacturing | 2016 |
| Miinan Kenkä Oy | Wholesale & retail | 2003 |
| Mr TTF Entertainment Oy | Arts & recreation | 2021 |
| Mr TTF Profit Oy | Real estate | 2021 |
| MyPa 47 OY | Real estate | 2016 |
| Myllykosken Autotarvike Oy | Wholesale & retail | 2006 |
| Myllykosken Fysikaalinen Hoitolaitos Oy | Health & social care | 1984 |
| Myllykosken Kerho Oy | Hospitality | 2018 |
| Myllykosken Lasi Ky | Construction | 1979 |
| Myllykosken Seuratalo Oy | Real estate | 2016 |
| Myllykosken Sora Ky | Mining & quarrying | 1966 |
| Myllykosken Yläpään vesiosuuskunta | Water & waste | 2003 |
| Myllykosken itäpuolen vesihuolto-osuuskunta | Water & waste | 2006 |
| Mylsän Kuppila Oy | Hospitality | 2013 |
| Myltek Oy | Manufacturing | 1999 |
| Mökkopi Oy | Administrative & support | 2019 |
| Nalle-Electric Uusimaa Oy | Construction | 2023 |
| Onnitili Oy | Professional & scientific | 2025 |
| Osmankammi Oy | Real estate | 1976 |
| Osuuskunta Nivalan Työtukku | Administrative & support | 1995 |
| Parturi-Kampaamo Porvari Oy | Other services | 1985 |