| Skullerud Eiendom AS | Real estate | 2023 |
| Smaael Eiendom AS | Real estate | 2023 |
| Smaalenene Bygg AS | Construction | 2015 |
| Smaalenene Elektro AS | Construction | 2019 |
| Smaalenene Entreprenør Holding AS | Construction | 2020 |
| Smaalenene Takst AS | Real estate | 2020 |
| Soca Invest AS | | 2024 |
| Start Mangfold AS | Professional & scientific | 2022 |
| Stein Borud Drift AS | Wholesale & retail | 2024 |
| Stene Johansen AS | Administrative & support | 2012 |
| Strandkås Bygg AS | Construction | 2018 |
| Strandkås Eiendom AS | Construction | 2020 |
| Strandkås Holding AS | Construction | 2017 |
| Strønes Snekkerverksted AS | Manufacturing | 2015 |
| Suntree Holding AS | | 2018 |
| SV Team AS | Construction | 2022 |
| Svein Erik Westgaard Holding AS | | 2017 |
| Sørli Gård Trøgstad Da | Agriculture & fishing | 2017 |
| Søstrene Garsrud Da | Real estate | 2009 |
| Tgkstudio AS | Wholesale & retail | 2023 |
| TGN Agri Da | Agriculture & fishing | 2001 |
| To Gode Naboer AS | Manufacturing | 2018 |
| TP Haga AS | Wholesale & retail | 2022 |
| Trollerud Transport AS | Transport & logistics | 2016 |
| Trøgstad Auksjonsforretning Ans | Wholesale & retail | 1988 |
| Trøgstad Bensinstasjon AS | Wholesale & retail | 2015 |
| Trøgstad Bil Og Maskinservice AS | Wholesale & retail | 2016 |
| Trøgstad Bygg Og Trelast AS | Real estate | 1987 |
| Trøgstad Dyreklinikk AS | Professional & scientific | 2016 |
| Trøgstad Gård Da | Agriculture & fishing | 2021 |
| Trøgstad Handel AS | Wholesale & retail | 2017 |
| Trøgstad Kornsilo Og Mølle SA | Manufacturing | 1970 |
| Trøgstad Sparebank | Financial services | 1847 |
| Trøgstad Sparebank Eiendom AS | Real estate | 2000 |
| Trøgstad Tannlegesenter AS | Health & social care | 2022 |
| Trøgstad Torg 1 AS | Real estate | 2020 |
| Trøgstad Xpress AS | Arts & recreation | 2008 |
| Tømrer Lars Henrik Moe AS | Construction | 2018 |
| Tømrermester Jan Vidar Nes AS | Construction | 2019 |
| Valor Kapital AS | | 2025 |
| Veieierlaget Privatveien Iskleiva - Sætherbakken SA | Real estate | 1996 |
| Versalift Norge AS | Wholesale & retail | 2023 |
| Vesle Skrammerud 3 AS | Real estate | 2021 |
| Vestlia Bygg AS | Construction | 2015 |
| Veterinær Svein H Bakke AS | Professional & scientific | 2001 |
| Vibe Service AS | Manufacturing | 2012 |
| Vidar Strand Motor AS | Wholesale & retail | 2013 |
| Virano AS | Professional & scientific | 2026 |
| Vom Og Hundemat AS | Manufacturing | 1988 |
| VR Training Norge AS | Education | 2025 |
| Wecyveien 2 AS | Real estate | 2023 |
| Wind Dancer Ans | | 1994 |
| Åsland AS | Real estate | 2015 |
| Østeby Da | Agriculture & fishing | 2025 |
| Østfold Maskin AS | Construction | 2014 |
| Østfold Ventilasjonsservice AS | Construction | 2022 |
| Østfoldarv AS | Professional & scientific | 2025 |