| Sukellus Haaja Oy | Construction | 1992 |
| Sukitus-Pojat Oy | Construction | 2018 |
| Sunflower FIOY Oy | Hospitality | 2022 |
| Suomen Kaapelirata-asennus Oy | Manufacturing | 2007 |
| Suomen Laatupinta Oy | Construction | 2021 |
| Suomen Laatuteline Oy | Construction | 2008 |
| Suomen Luottovalvonta Oy | Administrative & support | 2011 |
| Suomen Lämpöteknikot Oy | Construction | 2023 |
| Suomen Mikrosementti Oy | Wholesale & retail | 2023 |
| Suomen Pointex Oy | Manufacturing | 1996 |
| Suomen Rakennusteknikot Oy | Construction | 2023 |
| Suomen Talouslaskenta Oy | Professional & scientific | 2020 |
| Suomen Traktoritarvike Oy | Wholesale & retail | 2011 |
| Suomen Turvalukko Oy | Wholesale & retail | 2018 |
| Suple Oy | Manufacturing | 1993 |
| Sureville Oy | Wholesale & retail | 2020 |
| Suunnittelutoimisto Ser-Plan Oy | Professional & scientific | 2016 |
| Svanel Engineering Ky | Professional & scientific | 1989 |
| SwanMedica Oy | Wholesale & retail | 2016 |
| Sweet Rain Oy | Health & social care | 2007 |
| Sähkö Ami Ky | Construction | 2012 |
| Sähkösuunnittelu Seppälä Oy | Professional & scientific | 2020 |
| Sähkötekniikka Nissinen Oy | Construction | 2019 |
| T Peräkylä Ky Kukkakauppa ja Hautaustoimisto | Other services | 1959 |
| T&J Huumonen Oy | Health & social care | 2019 |
| T-market Könönpelto Avoin Yhtiö | Wholesale & retail | 1989 |
| TH Solutions Oy | Manufacturing | 2015 |
| THEM Products Oy | Wholesale & retail | 2016 |
| TIDConsulting Oy | Professional & scientific | 2019 |
| TJ Pinewood Oy | Professional & scientific | 1981 |
| TJTV-Asennus Oy | Construction | 2020 |
| TK Monitoimi OY | Other services | 2019 |
| TMK-Trans Oy | Transport & logistics | 2011 |
| TT-Ilmastointi Oy | Construction | 1989 |
| TTS-Trading Oy | Wholesale & retail | 1993 |
| TV-Luksi Oy | Wholesale & retail | 1979 |
| Taidekeskus Väinölä Ky | Wholesale & retail | 1998 |
| Taikalaakso Avoin yhtiö | Arts & recreation | 2010 |
| Taitosakset Ky | Other services | 2004 |
| Taitotuote Oy | Manufacturing | 2008 |
| Taksi Puhos Oy | Transport & logistics | 2024 |
| Talopalvelu Pekka Kinnunen Ky | Wholesale & retail | 1983 |
| Talopalvelu Simo Koponen Oy | Wholesale & retail | 2004 |
| Tarja Voutilainen Ky | Hospitality | 2006 |
| Tarutuulia Oy | Professional & scientific | 2021 |
| Taskisen Puu Oy | Wholesale & retail | 1996 |
| Taulumäen koru-kello Oy | Wholesale & retail | 2011 |
| Team Bush Oy | Agriculture & fishing | 2024 |
| Teemu Lappi Oy | Other services | 2023 |
| Tekee HeKe metsänhoitopalvelut Oy | Agriculture & fishing | 2021 |
| Tertunkulma OY | Real estate | 2026 |
| TieKieppi Oy | Real estate | 2022 |
| Tietokoneapu Compfix Ky | Information & communication | 2005 |
| Tili- ja yrityspalvelu Tarja Jurvanen Oy | Professional & scientific | 2014 |
| Tili-Severi Oy | Professional & scientific | 1996 |
| Tilihuiput Oy | Professional & scientific | 2022 |
| Tilimaijat Oy | Professional & scientific | 1976 |
| Tilintarkastus Jarmo Hirvonen Oy | Professional & scientific | 2007 |
| Tilipalvelu Taru Oy | Professional & scientific | 2020 |
| Tilisaarni Oy | Professional & scientific | 2020 |
| Tilitoimisto Sirpa Hämäläinen Oy | Professional & scientific | 1990 |
| Tipsi Oy | Real estate | 2025 |
| Tornados Oy | Administrative & support | 1989 |
| Toteemi Oy Tommin Toimisto | Professional & scientific | 1996 |
| Trade M. Häkkänen Ky | Wholesale & retail | 1990 |
| Traktori- ja Maatilapalvelu Räisänen Ky | Construction | 2001 |
| Tramppas 2000 Int Oy | Construction | 2002 |
| Tristan Service Oy | Wholesale & retail | 2019 |
| TuoHan Auto Oy | Wholesale & retail | 2003 |
| Tuomaan Rakennus Oy | Professional & scientific | 1997 |
| Turvalliset Ystävät Oy | Administrative & support | 2016 |
| Työosuuskunta Varkauden WARMA | Administrative & support | 1995 |
| UKKO-Engineering Oy | Manufacturing | 2024 |
| UKKO-FOOD Oy | Hospitality | 2016 |
| UKKO-Holding Oy | Administrative & support | 2024 |
| UKKO-PRODUCTS Oy | Manufacturing | 2023 |
| UKKO-STEAM Oy | Professional & scientific | 2016 |
| Ullan Lintu & Muusa Ky | Wholesale & retail | 1994 |
| Urban Street Kitchen Oy | Hospitality | 2025 |
| Urheiluhieroja Aki Nyyssönen Oy | Health & social care | 2024 |
| Uudenkaupungin Liikuntakeskus Salus Oy | Arts & recreation | 2009 |
| Uusiotek Electric Oy | Manufacturing | 2012 |
| VAN-palvelut Oy | Construction | 2011 |
| VJT Service Ky | Manufacturing | 2010 |
| Vk-Asennus OY | Construction | 2021 |
| VPR-Saneeraus Oy | Construction | 2010 |
| VT Media Oy | Information & communication | 2025 |
| VV-Work Oy | Wholesale & retail | 2003 |
| Valmis Consulting Oy | Professional & scientific | 2014 |
| Valter Juhlatilat Oy | Hospitality | 2025 |
| Varaosatalo Vitikainen Oy | Wholesale & retail | 1979 |
| Varfer Konepaja Oy | Manufacturing | 1995 |
| Varfer Oy | Manufacturing | 1987 |
| Varkauden AP-Trans Oy | Transport & logistics | 1996 |
| Varkauden Aito Oy | Manufacturing | 1993 |
| Varkauden Aluelämpö Oy | Energy | 1976 |
| Varkauden Aluetaksi Oy | Transport & logistics | 1978 |
| Varkauden Arboristi- ja Viherpalvelut Oy | Administrative & support | 2024 |
| Varkauden Asennuspalvelu Oy | Manufacturing | 1975 |
| Varkauden Asuntomarkkinat Oy | Real estate | 1993 |