| Rullestein Holding AS | | 2021 |
| Ryenbergveien 66 AS | Real estate | 2024 |
| Rådgivende Ingeniør Breistein AS | Professional & scientific | 2020 |
| Rørkompaniet AS | Construction | 1992 |
| Rørkompaniet Eiendom AS | Construction | 2004 |
| Røsten Holding AS | | 2021 |
| Røyken Næringspark Invest AS | Real estate | 2018 |
| S&N Property AS | Real estate | 2026 |
| Saeed Holding AS | | 2026 |
| Sage Holding AS | Construction | 2017 |
| Sagen Eiendomsutvikling AS | Real estate | 2015 |
| Salva Invest AS | Professional & scientific | 2010 |
| Sandvika Data AS | Wholesale & retail | 2017 |
| Sandvika Regnskapskontor AS | Professional & scientific | 1976 |
| SBM Holding AS | Wholesale & retail | 2005 |
| Scanova AS | Professional & scientific | 2013 |
| SCH AS | Professional & scientific | 2023 |
| Schwensensgate 5 AS | Real estate | 2006 |
| Seah AS | | 2020 |
| Seidr Technologies AS | Information & communication | 2025 |
| Semi Holding AS | Real estate | 2007 |
| Setanta AS | Professional & scientific | 2019 |
| Shimano Nordic AS | Wholesale & retail | 2005 |
| Sicubi AS | Administrative & support | 1996 |
| Sigel AS | Financial services | 2011 |
| Sigmund Olsen Agentur AS | Wholesale & retail | 1984 |
| Siluette Holding AS | | 2025 |
| Simtronics AS | Manufacturing | 2006 |
| Singsland AS | | 2020 |
| Sissel Flesland Markedsinformasjoner AS | Professional & scientific | 1995 |
| Siti AS | Arts & recreation | 2019 |
| Sittegodt AS | Professional & scientific | 2022 |
| SJK Invest AS | | 2021 |
| Skaugumåsen Kurssenter AS | Real estate | 1991 |
| Skinnegga Holding AS | | 2020 |
| SM Håndverkservice AS | Administrative & support | 2003 |
| Smal H AS | Financial services | 2020 |
| Smart Stall Da | Wholesale & retail | 2016 |
| Smartrepair AS | Other services | 2016 |
| Smed Larsens Eftf. AS | Information & communication | 2003 |
| Smeland Holding AS | | 2025 |
| SMP Proshop Ans | Wholesale & retail | 2003 |
| Smudfood AS | Information & communication | 2021 |
| Soft Wash AS | Other services | 1993 |
| Sonic Tours and Travel AS | Administrative & support | 2023 |
| Sordin AS | Real estate | 2015 |
| Spinnerfall AS | | 2021 |
| SR Holdingselskap AS | | 2018 |
| SR Prosjekt AS | Professional & scientific | 2018 |
| Stabekkvilla AS | Real estate | 2017 |
| Start Drift AS | Wholesale & retail | 2004 |
| Start Holding AS | Real estate | 1995 |
| Start Property AS | Real estate | 2011 |
| Steff Consult AS | Professional & scientific | 2023 |
| Steg II AS | Administrative & support | 2019 |
| Stem Holding AS | Real estate | 2021 |
| Stemmehaugen AS | Arts & recreation | 2016 |
| Stemware Da | Wholesale & retail | 2005 |
| Sterner Consult AS | Real estate | 2024 |
| Stine Torgersbråten AS | | 2026 |
| Stomix AS | Construction | 2017 |
| Stone Hotels Holding AS | Real estate | 2006 |
| Stonebridge Holding AS | | 2021 |
| Stoppen Møbeltapetsering AS | Other services | 2019 |
| Storelia Eiendom AS | Real estate | 2008 |
| Strand Media and Consulting AS | Professional & scientific | 2023 |
| Studio 1184 AS | Information & communication | 2025 |
| Sublima AS | Wholesale & retail | 2017 |
| Subsea Enterprises AS | Professional & scientific | 2006 |
| Sundfær Transport AS | Transport & logistics | 1989 |
| Svenor AS | Professional & scientific | 2024 |
| Swiss Tech Aps Nuf | Wholesale & retail | 2026 |
| Sygard Holding AS | | 2025 |
| Sygard Maskin AS | Construction | 2024 |
| Sølvveien AS | Real estate | 2018 |
| Takstmann Mosveen AS | Real estate | 2013 |
| Takstmann Stian Bagroen AS | Real estate | 2021 |
| Tashatone Music AS | Arts & recreation | 2024 |
| Teb AS | Professional & scientific | 2013 |
| Tedevelopment AS | Professional & scientific | 2022 |
| Tedmundsson Holding AS | | 2024 |
| Teeec AS | Financial services | 2006 |
| Thenor AS | Financial services | 2010 |
| Theodor Tonum Holding AS | Professional & scientific | 2015 |
| Thrane & Thrane | Real estate | 1989 |
| Thrane & Thrane Teknikk AS | Wholesale & retail | 1984 |
| Thrane Holding AS | Wholesale & retail | 1998 |
| Tipisocks AS | Wholesale & retail | 2022 |
| Tipsy Trading AS | | 2025 |
| Titan Regnskap AS | Professional & scientific | 2026 |
| TMG Tommygun Da | Information & communication | 2020 |
| Todoc AS | Health & social care | 2005 |
| Tomy Design AS | Professional & scientific | 2021 |
| Tore Frøland AS | Education | 2013 |
| Torgeir Haugen AS | | 2023 |
| Totality Facility Services AS | Administrative & support | 2016 |
| Transport Data Systems AS | Information & communication | 1999 |
| Treningsverket AS | Arts & recreation | 2021 |
| Trippelbygg AS | Real estate | 2017 |
| Tste Invest AS | Financial services | 2018 |