| T. Makkonen Oy | Real estate | 1963 |
| T.T Food & Cafe Oy | Hospitality | 2026 |
| TAPA-Natural Oy | Manufacturing | 2023 |
| TByteAetherWorks Oy | Information & communication | 2026 |
| TKT-Purku Oy | Wholesale & retail | 2019 |
| TNA Sijoitus Oy | Financial services | 2026 |
| TPu Palvelut Oy | Administrative & support | 2008 |
| TSH-Invest Oy | Professional & scientific | 2016 |
| TTJ-Kuljetus Oy | Transport & logistics | 2012 |
| Tahkon Keidas Oy | Real estate | 1989 |
| Taitosavo Ky | Construction | 2004 |
| Taksipalvelu K. Nissinen Ky | Transport & logistics | 2013 |
| Taksipalvelu Kumpulainen Oy | Transport & logistics | 2010 |
| Talo Oy Iisalmen Pohjolankatu 7 A | Real estate | 1972 |
| Tammikadun Metalli Oy | Manufacturing | 2025 |
| Tapani Uotinen Oy | Transport & logistics | 1994 |
| Tapio Leinonen Oy | Construction | 1994 |
| Tarlaco Invest Oy | Wholesale & retail | 1994 |
| Team Jokela Oy | Agriculture & fishing | 2019 |
| Team Quadratus Oy | Health & social care | 2015 |
| TehoLaser Oy | Administrative & support | 2024 |
| Tehoxi Oy | Arts & recreation | 2026 |
| Telipeli Oy | Construction | 2008 |
| Tepin Kebáb Grilli Ky | Hospitality | 1985 |
| Terapiapalvelut Hanne Pesonen Oy | Health & social care | 2021 |
| Terrieri Promotions Ky | Arts & recreation | 2015 |
| Terähuolto Putkonen Oy | Manufacturing | 1995 |
| Tesola Oy | Health & social care | 2021 |
| Tieseiska Oy | Manufacturing | 2011 |
| Tietorauta Ky | Wholesale & retail | 2011 |
| Tiina Honkanen Ky | Hospitality | 2007 |
| Tiinan Treenipalvelut Oy | Arts & recreation | 2014 |
| Tikano Oy | Health & social care | 2021 |
| TiliTabell Oy | Professional & scientific | 2024 |
| Tilitoimisto Ekonom Oy | Professional & scientific | 1990 |
| Tilitoimisto Satamatilit Oy | Professional & scientific | 2008 |
| Tilitoimisto Tuula Kauppinen avoin yhtiö | Professional & scientific | 2009 |
| Timaco Oy | Manufacturing | 1996 |
| Timosaurus Oy | Real estate | 2020 |
| Tolitec Oy | Construction | 2020 |
| TomPal Oy | Real estate | 2023 |
| Torf Oy | Agriculture & fishing | 2012 |
| Trans Partanen Oy | Transport & logistics | 1993 |
| Tuoppi-Kellari Oy | Hospitality | 1978 |
| Tuulensuoja Oy | Wholesale & retail | 2004 |
| Tuunela Motorsport Ky | Other services | 2006 |
| Twin Systems Oy | Transport & logistics | 1995 |
| Täsmätuotanto Oy | Arts & recreation | 2024 |
| UJ-Invest Oy | Financial services | 2011 |
| Ulmalan kansantalo Oy | Real estate | 2012 |
| Urakointiliike Leinonen Oy | Agriculture & fishing | 1977 |
| VICTORIS Oy | Professional & scientific | 2024 |
| VM Eristemestarit Oy | Construction | 2012 |
| Vaahteramäen Kiinteistöt Oy | Real estate | 2016 |
| Vainio Invest Oy | Financial services | 2020 |
| Vakuutus Tommi Ky | Construction | 2016 |
| Vakuutusmyynti A. Rissanen Oy | Financial services | 2023 |
| Vakuutuspalvelu Esko Nissinen Ky | Administrative & support | 2012 |
| Vakuutuspalvelut Ari Kärkkäinen Ky | Financial services | 2009 |
| Vakuutuspalvelut Ålander Oy | Financial services | 2014 |
| Vattumäki Oy | Mining & quarrying | 2016 |
| Vehka Group Oy | Agriculture & fishing | 2014 |
| Veijo Huttunen Ky | Construction | 1990 |
| Veljekset Balk avoin yhtiö | Agriculture & fishing | 2007 |
| Veljekset Heiskanen Oy | Wholesale & retail | 1998 |
| Video- ja TV-huolto Kaikkonen Oy | Other services | 1998 |
| Vierola & Vierola Oy | Health & social care | 2008 |
| Vierolan Vehkeet Oy | Administrative & support | 2019 |
| Viljo Keränen Ky | | 1982 |
| Villa Helmi Oy | Hospitality | 2002 |
| Ville Kosonen Oy | Education | 2025 |
| VintRem Ky | Administrative & support | 1990 |
| Virran Hulivili Oy | Hospitality | 2025 |
| Visu-IS Oy | Manufacturing | 2025 |
| Väisäsen Kotiliha Oy | Wholesale & retail | 1996 |
| Väli-Suomen Säiliöliikenne Oy | Transport & logistics | 1989 |
| WS Consulting Oy | Administrative & support | 2018 |
| Wanha Kukkakauppa ja hautaustoimisto avoin yhtiö | Wholesale & retail | 2003 |
| Weeksey Oy | Professional & scientific | 2026 |
| Wemase Oy | Manufacturing | 2026 |
| Wicked Customs Oy | Construction | 2020 |
| Wildwood Oy | Water & waste | 1993 |
| Workson Oy | Other services | 2020 |
| YS-Sähkö Oy | Construction | 1992 |
| Ykköstapahtumat Oy | Manufacturing | 1995 |
| Ylemmäisen Vesiosuuskunta | Water & waste | 2007 |
| Ylä Savon Varastointi ja Kuljetus Ky | Transport & logistics | 1987 |
| Ylä-Savon Automaalaus Oy | Other services | 2008 |
| Ylä-Savon Hyötyjäte Oy | Real estate | 1990 |
| Ylä-Savon Jakelu Oy | Transport & logistics | 2025 |
| Ylä-Savon Jätehuolto Oy | Water & waste | 1996 |
| Ylä-Savon Kiinteistötili Oy | Real estate | 1992 |
| Ylä-Savon LVI-Palvelu Oy | Construction | 1995 |
| Ylä-Savon Salaojapalvelu avoin yhtiö | Construction | 1983 |
| Ylä-Savon Sammutinhuolto Oy | Wholesale & retail | 2015 |
| Ylä-Savon Siipikarja Ky | Agriculture & fishing | 1985 |
| Ylä-Savon Siivoushuolto Siistiks Ky | Administrative & support | 1989 |
| Ylä-Savon Sora avoin yhtiö | Transport & logistics | 1987 |
| Ylä-Savon Vesi Oy | Water & waste | 2003 |
| Ysako Oy | Manufacturing | 1998 |