| Samir Fashion Oy | Wholesale & retail | 2021 |
| Samon1 Oy | Hospitality | 2014 |
| Sampo Consulting Oy | Information & communication | 2020 |
| Samrand Oy | Hospitality | 2020 |
| Samu Holding Oy Ab | Financial services | 2024 |
| Samuli Savo kommandiittiyhtiö | Construction | 1981 |
| Sandrew Metronome Video Finland Oy | Wholesale & retail | 2011 |
| Sane-Box Oy | Wholesale & retail | 2002 |
| Sankaripalvelut Oy | Administrative & support | 1982 |
| Sannos Oy | Hospitality | 2019 |
| Sapsan Group Oy | Wholesale & retail | 2023 |
| Sara Vanninen Oy | Professional & scientific | 2019 |
| Sarexia Oy | Wholesale & retail | 1996 |
| Sarres Mek Oy | Manufacturing | 2024 |
| Sastamalan Hitsauspalvelu Oy | Manufacturing | 2020 |
| Sata Palvelu Oy | Wholesale & retail | 2019 |
| Satakunnan Konetyö- ja korjaus Oy | Manufacturing | 2011 |
| Satakunnan Yritysrealisointi Oy | Professional & scientific | 2019 |
| Sateenkaari Perinnetaito Oy | Manufacturing | 1997 |
| Saturex Oy | Manufacturing | 2021 |
| Saucon Oy | Construction | 2022 |
| Sauna Saarinen Oy | Construction | 2005 |
| Saura Care Oy | Health & social care | 2023 |
| Savehub Oy | Real estate | 2015 |
| Savo-Karjalan Kiinteistösijoitus Oy | Real estate | 2018 |
| Savon Automyynti Oy | Wholesale & retail | 2018 |
| Savon Purkutyö Oy | Construction | 2017 |
| Savon Saneeraus Oy | Manufacturing | 2019 |
| Savon Sähkö Talkkari Oy | Construction | 2023 |
| Savon kestävä kiinteistökehitys Oy | Real estate | 2016 |
| Savottajätkä Oy | Agriculture & fishing | 2019 |
| SavuMesu Oy | Wholesale & retail | 2020 |
| ScanWorkers Oy | Administrative & support | 2022 |
| ScandWise Oy | Construction | 2020 |
| Scandbo Oy | Wholesale & retail | 2005 |
| Scandi Process Design Services Oy | Professional & scientific | 2015 |
| Scandic Automation Oy | Manufacturing | 2021 |
| Scandicwall Oy | Construction | 2021 |
| Scandinavia Crystal Oy | Wholesale & retail | 2011 |
| Scandinavian Financial Research Oy | Professional & scientific | 1991 |
| Scandinavian School of Creativity and Innovation Oy | Education | 2015 |
| Scandium Int. Mining Corp., Norway AS, Suomen sivuliike | Mining & quarrying | 2017 |
| Scanlia Oy | Wholesale & retail | 1996 |
| Scanwaste Oy | Water & waste | 2020 |
| Sceneve Oy | Professional & scientific | 2019 |
| Schmid capital Oy | Professional & scientific | 2022 |
| Schteinberg Oy | Arts & recreation | 2018 |
| Sciar Company Oy | Information & communication | 2018 |
| Scire Consulting Oy | Professional & scientific | 2022 |
| Score Suomi OY | Construction | 2023 |
| Seasong Fastighetsaktiebolag | Real estate | 2013 |
| Seawolf Studios Oy | Information & communication | 1997 |
| Securelyshare Software Oy | Information & communication | 2017 |
| Sedha Capital Oy | Professional & scientific | 2024 |
| Seed Investment Oy | Real estate | 2012 |
| Seed of Life Oy | Hospitality | 2019 |
| Seedsling Oy | Wholesale & retail | 2019 |
| Seinäjoen Ostoskaruselli Oy | Wholesale & retail | 1990 |
| Selected taxi Oy | Transport & logistics | 2019 |
| Self-Made Capital Oy | Professional & scientific | 2021 |
| Selivo Oy | Real estate | 2021 |
| Selkäveitti Oy | Construction | 2005 |
| Sema palvelu Oy | Administrative & support | 2023 |
| Seni-Kuljetus Ky | Transport & logistics | 2002 |
| Seniorfy Oy | Information & communication | 2021 |
| Senna Tuote Oy | Construction | 2020 |
| Seolocation Oy | Professional & scientific | 2015 |
| Separett Aktiebolag, Suomen sivuliike | Wholesale & retail | 2001 |
| Sepin Monitoimipalvelut oy | Wholesale & retail | 2024 |
| Seranix Oy | Wholesale & retail | 2021 |
| Serge Energy Oy | Energy | 2019 |
| Sergonen Oy | Construction | 2018 |
| Serviz Kunnontarkastus Oy | Professional & scientific | 2021 |
| Sevent Oy | Administrative & support | 1993 |
| Shades of Seduction Oy | Wholesale & retail | 2020 |
| Shadow Kitchen Oy | Real estate | 2020 |
| Shahi Dera Oy | Hospitality | 2022 |
| ShangShi Oy | Hospitality | 2021 |
| Shapla Oy | Hospitality | 2018 |
| Shareit.fi Oy | Administrative & support | 2015 |
| Sharma Capital Oy | Wholesale & retail | 2022 |
| Shiny Happy People Oy | Wholesale & retail | 2018 |
| Shisha Time Oy | Wholesale & retail | 2020 |
| Shop Locally Oy Ab | Information & communication | 2020 |
| Shugge Oy | Construction | 2021 |
| SiSan Oy | Education | 2024 |
| Siamac Oy | Transport & logistics | 1996 |
| Sibed Oy | Information & communication | 2018 |
| Sicilia Records Oy | Information & communication | 2020 |
| Sidibou oy | Administrative & support | 2022 |
| Siempro Oy | Construction | 2008 |
| Sievi Advisors Oy | Professional & scientific | 2022 |
| Signora Delizia Oy | Wholesale & retail | 2011 |
| Siili Consulting Oy | Professional & scientific | 2021 |
| Siilin Kiinteistöpalvelu Oy | Real estate | 2015 |
| Siilin Konsultointi Oy | Real estate | 1995 |
| Siivillä Oy | Hospitality | 2021 |
| Siivouspalvelu Puro Oy | Administrative & support | 2020 |
| Siivouspalvelu Puuvilla Oy | Administrative & support | 2021 |
| Siivouspalvelu Ruth Oy | Administrative & support | 2019 |