| Savon Metsänpoika Oy | Real estate | 2007 |
| Savon Pinnoitus Oy | Construction | 2019 |
| Savon PuuKoti Ky | Construction | 2014 |
| Savon Rakennus- ja Peltimestarit Oy | Construction | 2012 |
| Savon Sammutinhuolto Oy | Wholesale & retail | 1983 |
| Savon Sijoitus Oy | Real estate | 2007 |
| Savon Suhari Ky | Transport & logistics | 2003 |
| Savon Talohoito STH Oy | Administrative & support | 1988 |
| Savon Teollisuussuunnittelu Oy | Professional & scientific | 2024 |
| Savon Turvapalvelut Oy | Administrative & support | 2016 |
| Savon rafla Oy | Hospitality | 2022 |
| Savonia Health Oy | Wholesale & retail | 2025 |
| Savonlinja Oy | Transport & logistics | 1935 |
| Savonrannan Lämpö Oy | Energy | 1995 |
| Savoravintolat Ky | Hospitality | 2011 |
| Scaut Oy | Manufacturing | 2021 |
| Seilotek Oy | Professional & scientific | 2010 |
| Selamatic Oy | Administrative & support | 1995 |
| Semika Oy | Administrative & support | 2020 |
| Seniorskillshome Oy | Information & communication | 2024 |
| Sensio Oy | Construction | 1987 |
| Seppo Halinen Muuraus ja Rakennus Ky | Construction | 1990 |
| Seppo Leikas Ky | Manufacturing | 1950 |
| Seppo Pöyry Ky | Transport & logistics | 1991 |
| Serviini Oy | Hospitality | 2015 |
| Shishir Oy | Hospitality | 2021 |
| Show No Mercy Oy | Professional & scientific | 2026 |
| Siam Asia Oy | Wholesale & retail | 2022 |
| Siesu Capital Oy | Real estate | 2020 |
| Siikasalmen Vesiosuuskunta | Water & waste | 2004 |
| Siimet Oy | Manufacturing | 2020 |
| Siivonnaiset Oy | Administrative & support | 2012 |
| Siivotaankauppa.fi Oy | Wholesale & retail | 2024 |
| Sijoitusyhtiö Oravannahka Oy | Professional & scientific | 2011 |
| Sikumu Oy | Transport & logistics | 2010 |
| Sil-Kare Oy | Professional & scientific | 2002 |
| Sil-Kas Oy | Professional & scientific | 1992 |
| Silent Steel Oy | Manufacturing | 2020 |
| Silkkaa Voittoa Oy | Professional & scientific | 2023 |
| Silmuke Oy | Health & social care | 2018 |
| Simo Parkkinen Oy | Transport & logistics | 2006 |
| Sinsto Oy | Professional & scientific | 2020 |
| Sisustus-Hiili Oy | Professional & scientific | 2014 |
| Sisustusliike Laurikainen Ky | Wholesale & retail | 1991 |
| Sitex Oy | Real estate | 2009 |
| Siun Tuexi Oy | Health & social care | 2019 |
| Sivustosi Oy | Information & communication | 2022 |
| Ski Tornimäki Oy | Financial services | 1992 |
| Skinlux Aesthetic Clinic Oy | Other services | 2024 |
| SkuPia Oy | Manufacturing | 2017 |
| Smoke&Style Oy | Wholesale & retail | 2024 |
| Snikkeri Oy | Manufacturing | 2024 |
| SoSaimaa Oy | Hospitality | 2025 |
| Sodan ja rauhan keskus Muisti Oy | Arts & recreation | 2018 |
| Sofler Oy | Construction | 2018 |
| Soinvirta Oy | Construction | 2014 |
| Sola Holding Oy | Administrative & support | 2026 |
| Sote Solutions Oy | Professional & scientific | 2023 |
| Special request Oy | Education | 2024 |
| Spektrum Oy | Wholesale & retail | 2021 |
| Sportpalazzo Oy | Arts & recreation | 2021 |
| St Michel Print Oy | Manufacturing | 2002 |
| Stall Blombacke Oy | Arts & recreation | 2015 |
| Star Expert Oy | Construction | 2022 |
| Star Import Finland Oy | Wholesale & retail | 2011 |
| Steelmerit Oy | Manufacturing | 2003 |
| StellaRest Oy | Financial services | 2010 |
| Studio Emmiina Oy | Other services | 2026 |
| Studio Qheomi Oy | Professional & scientific | 2026 |
| Stuntman postimyynti Oy | Wholesale & retail | 1996 |
| Stupa Invest Oy | Professional & scientific | 1977 |
| Sulatosi Oy | Professional & scientific | 2024 |
| Sulkavan Lämpö Oy | Energy | 1995 |
| Summa Energy Projects Oy | Manufacturing | 2012 |
| Summerland Company Ky | Wholesale & retail | 2016 |
| Suomeksi Oy | Education | 2025 |
| Suomen Digi-Infra HoldCo Oy | Financial services | 2023 |
| Suomen Energiasaneeraus Oy | Construction | 2007 |
| Suomen Koti Katsastus Oy | Construction | 2024 |
| Suomen LVI-Invest Oy | Construction | 2010 |
| Suomen Talotekniikkainsinöörit Oy | Professional & scientific | 2020 |
| Suomen Voimaverkot Oy | Energy | 1995 |
| Suomen Yritysvälittäjä Oy | Professional & scientific | 2021 |
| Suomen kaasutekniikka Oy | Construction | 2014 |
| Suomen lämpötalo Oy | Construction | 2019 |
| Superlatik Oy | Manufacturing | 2017 |
| Surgical Ventures Oy | Health & social care | 2016 |
| Suunnittelu Anssi Bagge Oy | Professional & scientific | 2021 |
| Suunnitteluasema Etelä-Savo Ky | Professional & scientific | 2016 |
| Suur-Savon Energiahuolto Oy | Energy | 1989 |
| Suur-Savon Hautauspalvelu Oy | Other services | 2020 |
| Suur-Savon Osuuspankki | Financial services | 2011 |
| Suur-Savon Sijoitus Oy | Financial services | 1988 |
| Suur-Savon Sähkö Oy | Energy | 1946 |
| Suur-Savon Sähkökone Oy | Other services | 1995 |
| Suvi-Trading Oy | Manufacturing | 2017 |
| Sweet Spot Finland Oy | Wholesale & retail | 2023 |
| Sydän Mikkeli Oy | Health & social care | 2025 |
| Syncorp Oy | Wholesale & retail | 2007 |
| Syvtech Oy | Other services | 2019 |