| Stratox-Yrityspalvelut Oy | Professional & scientific | 1998 |
| Street Bagel & Bistro Oy | Hospitality | 2018 |
| Streetbaker Consulting Oy | Manufacturing | 2013 |
| Structural Geology Company Oy | Professional & scientific | 2023 |
| Ström & Ström Oy | Financial services | 2024 |
| Strömling Oy Ab | Construction | 2014 |
| Ströömin vesi ja viemäri oy | Water & waste | 2020 |
| Ströömin vesiosuuskunta | Water & waste | 2020 |
| StuRent Oy | Administrative & support | 2021 |
| Studio 42 Oy | Information & communication | 2020 |
| Studio Auran Kuva Oy | Professional & scientific | 1964 |
| Studio Bette Eklund Oy | Professional & scientific | 2020 |
| Studio Brahe avoin yhtiö | Professional & scientific | 1984 |
| Studio Emiliet Oy | Professional & scientific | 2026 |
| Studio Grandé nails oy | Other services | 2025 |
| Studio Hinni Oy | Professional & scientific | 2023 |
| Studio Kalon Oy | Other services | 2021 |
| Studio Korkeila Oy | Manufacturing | 2021 |
| Studio Kummatus osk | Information & communication | 2025 |
| Studio Pixart Rauno Johansson Oy | Professional & scientific | 1997 |
| Studio Soul Sisters avoin yhtiö | Other services | 2012 |
| Studio Ykkönen Oy | Other services | 2024 |
| Stuman Oy Ltd | Hospitality | 2003 |
| Stuuga Oy | Hospitality | 2021 |
| StyleRide Oy | Wholesale & retail | 2014 |
| Ståfast Oy Ab | Real estate | 2008 |
| Ståhl Solutions Oy | Construction | 2022 |
| Sub Nordic Oy | Hospitality | 2005 |
| Sub-Electronics Ky | Manufacturing | 1994 |
| Sub-Nella Oy | Hospitality | 2005 |
| Sub-Works oy | Manufacturing | 2018 |
| Subito Oy | Health & social care | 2006 |
| Success Goals Nordic Oy | Education | 2022 |
| Sud Elegance Oy | Manufacturing | 2006 |
| Sudden Solution Oy | Wholesale & retail | 2001 |
| Suerteksas Oy | Manufacturing | 2013 |
| SugarFree Ab | Professional & scientific | 2021 |
| Sugo Oy | Hospitality | 2020 |
| Suikkilan Lämpö Oy | Administrative & support | 1966 |
| Suju-plast Ky | Real estate | 1983 |
| Sukari Capital Oy | Arts & recreation | 2012 |
| Sukari Invest Oy | Financial services | 2017 |
| Sukari Konserni Oy | Real estate | 1987 |
| Sukellus Backman Oy | Construction | 2014 |
| Sulcunic Oy | Financial services | 2023 |
| Sulihe Oy | Financial services | 2024 |
| Sultanin Group Oy | Construction | 2020 |
| Summa ja mutikka Oy | Professional & scientific | 2020 |
| Summerhills Group Oy Ab | Professional & scientific | 2024 |
| SumuPlan Oy | Professional & scientific | 2016 |
| Sun 4 Oy | Energy | 2023 |
| Sun 5 Oy | Energy | 2023 |
| Sun 6 Oy | Energy | 2023 |
| Sun Lion Oy | Administrative & support | 2017 |
| Sun Marianne Oy | Real estate | 2004 |
| Sun Riste Oy | Energy | 2023 |
| Sun Suu Oy | Health & social care | 2009 |
| Sun Telja Oy | Energy | 2023 |
| Sun Voimala Oy | Construction | 2022 |
| SunArt Savanna avoin yhtiö | Wholesale & retail | 2013 |
| SunCare Oy | Health & social care | 2016 |
| SunSub Oy | Hospitality | 2007 |
| Sunborn Development Oy | Transport & logistics | 2016 |
| Sunborn Events Oy | Hospitality | 1999 |
| Sunborn Finance Admin Oy | Professional & scientific | 2018 |
| Sunborn Finance Oy | Hospitality | 2017 |
| Sunborn Helsinki Personell Oy | Administrative & support | 2019 |
| Sunborn International Holding Oy | Administrative & support | 2020 |
| Sunborn International Oyj | Administrative & support | 2018 |
| Sunborn London Admin Oy | Administrative & support | 2019 |
| Sunborn London Oyj | Administrative & support | 2016 |
| Sunborn Oy | Professional & scientific | 1975 |
| Sunborn Personell Oy | Administrative & support | 2017 |
| Sunborn Ravintolakiinteistöt Oy | Hospitality | 2004 |
| Sunborn Saga Oy | Hospitality | 1997 |
| Sunborn Vacation Club 1 Oy | Real estate | 2004 |
| Sunday Brunch Company Oy | Professional & scientific | 2023 |
| Sunday Productions Oy | Wholesale & retail | 2022 |
| Sunell & Nyström Oy | Professional & scientific | 2025 |
| Sunfest Oy | Arts & recreation | 2020 |
| Sunfish Finland Oy | Education | 2022 |
| Suni Capital Oy | Financial services | 2026 |
| Sunnan Oy | Administrative & support | 1996 |
| Sunnet-consulting Oy | Professional & scientific | 1995 |
| Sunrise Networking Oy | Wholesale & retail | 2017 |
| Sunshine Boating Oy | Administrative & support | 2022 |
| Suntrail Oy | Professional & scientific | 2020 |
| Suoja Lastensuojelu Oy | Health & social care | 2023 |
| SuojaaSe Oy | Wholesale & retail | 2015 |
| Suomalainen Invest Oy | Financial services | 2026 |
| Suomen Ajoneuvopantti Oy | Financial services | 2025 |
| Suomen Ankkurityö Oy | Construction | 2024 |
| Suomen Arkistovoima Oy - SAVe Ltd. | Information & communication | 1994 |
| Suomen Arvohuoneistot Oy | Real estate | 2015 |
| Suomen Arvokiinteistöt Oy | Real estate | 1991 |
| Suomen Ase Budo ja Erä Oy | Wholesale & retail | 1986 |
| Suomen Asuntorakennus Oy | Real estate | 2021 |
| Suomen Asuntosijoitustiimi Oy | Real estate | 2022 |
| Suomen Burger-Staff Oy | Administrative & support | 1998 |
| Suomen Burgerserve Oy | Administrative & support | 2002 |