| Slemmestad Fysikalske AS | Health & social care | 2025 |
| Slemmestad Handtverk Invest | | 2020 |
| Slemmestad Karosseri Og Lakk AS | Other services | 2016 |
| Slemmestad Maskinutleie AS | Administrative & support | 2025 |
| Slemmestad Optikk AS | Wholesale & retail | 1995 |
| Snekker Jacobsen AS | Construction | 2022 |
| SNUS365 AS | Wholesale & retail | 2022 |
| Sol Regnskap AS | Professional & scientific | 2012 |
| Sport 1 Slemmestad AS | Wholesale & retail | 2021 |
| Stabæk AS | Wholesale & retail | 2021 |
| Stenslet Consulting AS | Professional & scientific | 2019 |
| Stenvaag Jeppesen AS | | 2024 |
| Stepper Inn AS | Other services | 2024 |
| Stine Invest AS | Real estate | 2008 |
| Strategos AS | Professional & scientific | 2023 |
| Stuedal Holding AS | Administrative & support | 2023 |
| STW Consult AS | Professional & scientific | 2020 |
| Sunn Verdiforvaltning AS | Professional & scientific | 2011 |
| Svein Transeth Eiendom AS | Real estate | 2009 |
| Svein Transeth Sportswear AS | Wholesale & retail | 2009 |
| Swisspearl Norge AS | Wholesale & retail | 2002 |
| Slemmestad Bensinstasjon AS | Wholesale & retail | 1987 |
| Taaffeit AS | Other services | 2020 |
| Tannlegen På Bryggen AS | Health & social care | 2024 |
| Tannlegene I Doktorgården AS | Health & social care | 2012 |
| Technocon AS | Professional & scientific | 2024 |
| Teknisk Gulv AS | Construction | 2020 |
| TGS Security AS | Professional & scientific | 1987 |
| The 4S&D AS | Professional & scientific | 1998 |
| Thermo AS | Wholesale & retail | 1992 |
| Thronvig Forvaltning AS | Real estate | 1987 |
| Tomt & Hageservice AS | Construction | 2022 |
| Top Speed Auto AS | Other services | 2014 |
| Tore S Holding AS | | 2025 |
| Tore S Invest AS | | 2025 |
| TR Hansen AS | Education | 2018 |
| Transeth Invest AS | Wholesale & retail | 2017 |
| Transition AS | Professional & scientific | 2024 |
| Trivsel Fysio- Og Manuellterapi Da | Health & social care | 2023 |
| TRM AS | | 2018 |
| TTH Holding AS | Financial services | 2005 |
| Tåjestranda Invest AS | Wholesale & retail | 2022 |
| Tømrer Kjartansson AS | Construction | 2020 |
| Tømrertjenester AS | Construction | 2013 |
| Urban Reuse AS | Construction | 2018 |
| Urban Reuse Norway AS | Construction | 2005 |
| Varelageret AS | Wholesale & retail | 2020 |
| Vaskegata AS | Other services | 2024 |
| Vaterland Pizzaservice Da | Hospitality | 1992 |
| Veas AS | Water & waste | 2017 |
| Veas Marked AS | Energy | 2018 |
| Veas Selvkost AS | Water & waste | 2017 |
| Vedlike AS | Manufacturing | 2003 |
| Vedlikeholding AS | | 2024 |
| Veglaget Romsås - Nordølum SA | Real estate | 1981 |
| Vet Epistat AS | Professional & scientific | 2022 |
| Viken Elektro AS | Construction | 2012 |
| Viromedica AS | Wholesale & retail | 2024 |
| Virvel Media AS | Professional & scientific | 2019 |
| Vollen Båtservice AS | Manufacturing | 2014 |
| Vollen Motor AS | Manufacturing | 2014 |
| Weber-Haugen Investering Ltd Nuf | Administrative & support | 2015 |
| Whitefield AS | Real estate | 2008 |
| Wild Gear AS | Wholesale & retail | 2020 |
| Wilsbeck Sjømat AS | Wholesale & retail | 2017 |
| Winge Bygg AS | Construction | 2016 |
| Workman Norway AS | Arts & recreation | 2021 |
| Østlandske Eiendom Ans | Professional & scientific | 1990 |
| Øye Bygg AS | Construction | 2024 |
| Øye Vedlikehold AS | Construction | 2018 |