| Opes Sarpsborg AS | Real estate | 2016 |
| Osti Invest AS | | 2015 |
| Paal Holding AS | Real estate | 2014 |
| PB Holding AS | Professional & scientific | 2006 |
| Per H. Nordal AS | Transport & logistics | 2024 |
| Pica AS | Real estate | 2023 |
| Pro Va AS | Construction | 2024 |
| QMS Nordic AS | Wholesale & retail | 2026 |
| Ressurshuset Ans | Professional & scientific | 1988 |
| Rie Ernst Holte AS | | 2023 |
| Riisløkka 32 AS | Real estate | 2023 |
| Robua AS | Health & social care | 2025 |
| Roka Invest AS | Financial services | 2005 |
| Ruden Nordic Well Logging Services AS | Administrative & support | 2021 |
| Sandbukta Og Vadsund Va-Selskap SA | Water & waste | 2007 |
| Sendas Invest & Consulting AS | Professional & scientific | 2007 |
| Sensor Systems AS | Administrative & support | 2015 |
| Sivilarkitekt Tom - Rich. Kristiansen AS | Professional & scientific | 2013 |
| Sjøbua V/Brødrene Nilsen Da | Real estate | 2013 |
| Skolebakken 6 AS | Real estate | 2014 |
| Skontorp Ressurssenter AS | Health & social care | 2025 |
| Skontorp Vikartjenester AS | Administrative & support | 2017 |
| Skovly Veilag SA | Real estate | 2022 |
| Små Lune Hjem Da | Wholesale & retail | 2004 |
| Snuta AS | Real estate | 1998 |
| Solhaug Feriekoloni AS | Real estate | 2025 |
| Spanien Holding AS | | 2025 |
| Stene Vestre Holding AS | | 2026 |
| Stene Vestre Invest AS | | 2025 |
| Stenebråten Fisk AS | Agriculture & fishing | 2025 |
| Stenebråten Fritidsboliger AS | | 2009 |
| Stenebråten-Bil AS | Other services | 2011 |
| Storm Event AS | Arts & recreation | 2002 |
| Studio KL AS | Wholesale & retail | 2026 |
| Sønnavin AS | Wholesale & retail | 2016 |
| Tecca Holding AS | Real estate | 2004 |
| TH Gressvik Ans | Real estate | 2022 |
| Thommessen Partners AS | Professional & scientific | 2025 |
| Thommessen Venture Lab AS | | 2025 |
| Ting Med Tang AS | Agriculture & fishing | 2016 |
| Tobiastårnet Holding AS | | 2025 |
| Toini AS | Information & communication | 2019 |
| Trollfeltet AS | Real estate | 2018 |
| Trulow AS | Real estate | 1997 |
| Trysil Mountain Resort AS | Real estate | 2019 |
| Tvetech AS | Professional & scientific | 2017 |
| Unbrako Holding AS | | 2025 |
| Uniteam AS | Administrative & support | 2018 |
| Varmepumpethor AS | Construction | 2025 |
| Vemol Holding AS | | 2025 |
| Vår Omsorg AS | Health & social care | 2018 |
| Yousafe AS | Administrative & support | 2016 |
| Yousafe Ny AS | Wholesale & retail | 2026 |
| Østfold Olje Ragnar Larsen & Sønner AS | Wholesale & retail | 1992 |
| Østfold Oljefyringsservice AS | Construction | 1971 |
| Øyvind Mathias Fonn Holding AS | | 2015 |