| Solar India Investment Oy | Manufacturing | 2023 |
| Solar Nigeria Investment Oy | Manufacturing | 2023 |
| Solarm Oy | Administrative & support | 1994 |
| Solvomate Oy | Professional & scientific | 2017 |
| Solweig Group Oy | Manufacturing | 2019 |
| Someron Panimo Oy | Manufacturing | 2015 |
| Somesto Oy | Information & communication | 2017 |
| Soraliike Hevi Arvo Oy | Mining & quarrying | 2023 |
| Sorv-Elektro Oy | Manufacturing | 1986 |
| Sosiaalipalvelut Irma Lehtonen Oy | Health & social care | 2016 |
| Soveco Oy | Information & communication | 2016 |
| Spa Pros Oy | Other services | 2022 |
| Sporteekki Oy | Wholesale & retail | 1996 |
| Statcon Oy | Information & communication | 1988 |
| Steelsalo Oy | Professional & scientific | 2013 |
| Sterling Eleven Oy | Financial services | 2012 |
| Strategiatislaamo Oy | Professional & scientific | 2018 |
| Streetbarber avoin yhtiö | Other services | 2024 |
| Stremet Holding Oy | Professional & scientific | 2007 |
| Stremet Oy | Manufacturing | 2017 |
| Studio Haven Oy | Arts & recreation | 2022 |
| Studio Kaisa Syväsalmi Oy | Professional & scientific | 2003 |
| Sukellus ja Saneeraus Olsbo Oy | Construction | 2017 |
| Sulaon Oy | Information & communication | 2005 |
| Sulkakauppa Oy | Wholesale & retail | 2025 |
| Suomen Ak-asennusteam OY | Construction | 2024 |
| Suomen Autotuonti Oy | Other services | 2005 |
| Suomen Bestand Oy | Financial services | 1992 |
| Suomen Event Logistics Oy | Transport & logistics | 2023 |
| Suomen Infraverkot Oy | Professional & scientific | 2018 |
| Suomen Juhlamusiikkipalvelu Oy | Arts & recreation | 2020 |
| Suomen Kulta ja Hopea Oy | Wholesale & retail | 2011 |
| Suomen Kylmäkuljetus Oy | Transport & logistics | 2013 |
| Suomen LVI-Service Oy | Construction | 1996 |
| Suomen Lasertyö Oy | Construction | 2020 |
| Suomen Nanopinnoite Oy | Construction | 2019 |
| Suomen Tuoresäilytys Oy | Manufacturing | 1992 |
| Suomen Vahinkohallintakeskus Oy | Real estate | 1991 |
| Suomen Vuokrakaksiot Oy | Real estate | 2021 |
| Suomen monipalvelu Oy | Construction | 2023 |
| Sushimoko Oy | Hospitality | 2024 |
| Suunnittelu Isotalo Oy | Professional & scientific | 2021 |
| Suunnittelutekniikka Kitula Oy | Professional & scientific | 1989 |
| Suuntavaisto Media Oy | Professional & scientific | 2023 |
| Suur-Salon Tukipalvelut Oy | Health & social care | 2007 |
| SuurSalon Talotekniikka Oy | Construction | 2016 |
| Suutari Ari Lehto Oy | Other services | 2021 |
| Suvanna Kitchen Oy | Hospitality | 2024 |
| Sähkö-COM Oy | Construction | 1987 |
| Sähköasennus Louhi Oy | Construction | 2023 |
| Sähköhuolto Lasse Vainio Oy | Construction | 2014 |
| Sähköpalvelu Pekka Kuoppa Oy | Construction | 1994 |
| Särki Oy | Manufacturing | 1985 |
| T&R Laakso Oy | Professional & scientific | 2008 |
| T&S Kaartinen Oy | Wholesale & retail | 2018 |
| T. Koli Oy | Administrative & support | 2014 |
| Taipo OY | Wholesale & retail | 2016 |
| TAP-Service Oy | Manufacturing | 1992 |
| Tegh OY | Hospitality | 2025 |
| Teijon Ravintolapalvelut OY | Hospitality | 2006 |
| THEONE Oy Ltd | Wholesale & retail | 2019 |
| TJ-Works Oy | Construction | 2021 |
| TL- Auto ja Caravan Oy | Wholesale & retail | 2025 |
| TLLV-Sijoitus Oy | Financial services | 2001 |
| TMM-Group Oy | Professional & scientific | 2021 |
| TMT Yhtiöt Oy | Construction | 2025 |
| TMT-Suunnittelu Oy | Real estate | 1985 |
| TN-lehti Oy | Manufacturing | 1983 |
| TRADESTA Oy | Wholesale & retail | 2017 |
| TRS Turva Oy | Financial services | 2022 |
| Tta-Group OY | Administrative & support | 2010 |
| TVU-Group Oy | Real estate | 2018 |
| Taikala Oy | Information & communication | 2009 |
| Taike Oy | Manufacturing | 1997 |
| Taitos Oy | Professional & scientific | 2016 |
| Takatalo Oy | Wholesale & retail | 1981 |
| Takatalo Service Oy | Manufacturing | 2024 |
| Takatalo Store Oy | Wholesale & retail | 2018 |
| Takatalon Korjaamo Oy | Administrative & support | 1987 |
| Taksi Mikko Pyykkö Oy | Transport & logistics | 2023 |
| Taksi Seppo Hietanen Oy | Transport & logistics | 2013 |
| Taksipalvelu Tiina Sorola Oy | Transport & logistics | 2011 |
| Talo ja tarkastus Oy | Professional & scientific | 2007 |
| Talokoski Oy | Construction | 2003 |
| Talotelli Oy | Construction | 2011 |
| Tanssiorkesteri Fernanda avoin yhtiö | Arts & recreation | 2018 |
| Tapila Oy | Real estate | 2026 |
| Tarvasjoen Teräsovi Oy | Manufacturing | 1986 |
| Tassuvahti Oy | Other services | 2016 |
| TeKald Spray Oy | Other services | 2019 |
| TeamFil Oy | Manufacturing | 2025 |
| Tehdasaukion Kiinteistö Oy | Real estate | 1984 |
| Tehdasprojektihallinta EPCM Suomi Oy | Professional & scientific | 2019 |
| Teijon Kuunari I Oy | Real estate | 1988 |
| Teijon Kuunari II Oy | Real estate | 1989 |
| Teijon Priki I Oy | Real estate | 1987 |
| Teito Oy | Wholesale & retail | 2007 |
| TelineSalo Oy | Administrative & support | 2019 |
| Teninvest Oy | Financial services | 2025 |
| Tepic Oy | Professional & scientific | 2025 |