| Scandinavian Style AS | Other services | 2024 |
| Scandinavian Vibes AS | Information & communication | 2015 |
| Scando Fusion AS | Wholesale & retail | 2013 |
| Schjetne Group AS | | 2024 |
| Schmidt & Smule Da | Professional & scientific | 1997 |
| Scylla AS | | 2016 |
| Sea Partners AS | Transport & logistics | 2005 |
| Seed Consulting AS | Professional & scientific | 2017 |
| Seiløe Consult AS | Wholesale & retail | 2010 |
| Seime Consulting AS | Information & communication | 2017 |
| Selmann Design AS | Professional & scientific | 2013 |
| Semb Invest AS | | 1995 |
| Senitnor AS | Professional & scientific | 2018 |
| Sento Magnum AS | Manufacturing | 2018 |
| Septem Invest AS | | 2019 |
| Sequoia Invest AS | | 2005 |
| Serendipity AS | Information & communication | 2014 |
| Seterlund AS | Financial services | 2013 |
| Settergren AS | Wholesale & retail | 2012 |
| SG Medskin AS | Health & social care | 2022 |
| Sha Pro AS | Health & social care | 2025 |
| Sideout AS | Education | 2022 |
| Signaturklinikken Bekkestua AS | Other services | 2020 |
| Signaturklinikken Eiendom RH AS | Other services | 2022 |
| Sigurd Olsvold AS | Real estate | 1983 |
| Silurveien 11A AS | | 2022 |
| Singh Investment AS | | 2020 |
| Sisco Consult AS | Administrative & support | 2005 |
| Sivilingeniør Giert Aasheim AS | Professional & scientific | 1970 |
| Sjåføren AS | Transport & logistics | 2017 |
| Skaubo AS | Education | 2011 |
| Skaubo Eiendom AS | Real estate | 2011 |
| Skaubo Holding AS | Real estate | 2011 |
| Skaubo Lager E16 AS | Real estate | 2014 |
| Skaubo Service AS | Manufacturing | 1985 |
| Skavino AS | Professional & scientific | 2022 |
| Skoleporten Ans | Information & communication | 2000 |
| Slaraff Invest AS | Real estate | 2007 |
| Slepenveien 48 AS | Real estate | 2010 |
| Sluttåm AS | Real estate | 2016 |
| Slåtterøy AS | Real estate | 1979 |
| SM Solutions AS | Professional & scientific | 2025 |
| Smhp Invest AS | | 2019 |
| Snarøya Barnehage AS | Education | 2023 |
| Snipp Snapp AS | Professional & scientific | 2001 |
| Snute Invest AS | Real estate | 2005 |
| Snøkorn AS | | 2025 |
| Soeik AS | Wholesale & retail | 2005 |
| Sokse AS | Real estate | 2026 |
| Solection AS | Wholesale & retail | 2021 |
| Solheimsnes Holding AS | Financial services | 2018 |
| Somniferum AS | Real estate | 2009 |
| Sophol AS | | 2018 |
| Spillforlaget Da | Information & communication | 2020 |
| Sport & Profil AS | Professional & scientific | 2004 |
| Stabekkslottet AS | Real estate | 2026 |
| Stabæk Fotball AS | Arts & recreation | 2006 |
| Stanley Invest AS | Professional & scientific | 2008 |
| Stav-Noraas Holding AS | | 2020 |
| Stave & Sønner AS | | 2025 |
| Stefan Ekberg Arkitekter AS | Professional & scientific | 2015 |
| Steffensen Engineering AS | Professional & scientific | 2013 |
| Steinar Engebretsen AS | | 2025 |
| Steinar Heiberg AS | Health & social care | 2023 |
| Stellander Invest AS | | 2024 |
| Stenor AS | Manufacturing | 1984 |
| Sterk Helse Og Trening Nadderud AS | Arts & recreation | 2026 |
| Sterma Moneta AS | | 2023 |
| Stichting Nederlandse Taal En Cultuur Oslo | Education | 2008 |
| Stila Interiør & Styling AS | Professional & scientific | 2015 |
| Stonefree Holding AS | Financial services | 2018 |
| Stonehard Capital AS | | 2025 |
| Storaas Og Co Holding AS | | 2025 |
| Storaas VVS AS | Construction | 2026 |
| Storkiosk 6055 Mahdi Ans | Wholesale & retail | 2003 |
| Storkleiven AS | Administrative & support | 1990 |
| Strategisk Bedriftsutvikling AS | Professional & scientific | 2013 |
| Strategy-Aid AS | Information & communication | 2025 |
| Stratfox AS | Professional & scientific | 2016 |
| Stuvodden AS | Administrative & support | 2005 |
| Styreleder Partner AS | Professional & scientific | 2026 |
| Summit Development AS | | 2016 |
| Sunhome Invest AS | | 2019 |
| Sunshine Holding AS | | 2018 |
| Super Magnus Holding AS | Wholesale & retail | 2022 |
| Super Tectum AS | Hospitality | 2020 |
| Svaddevegen 141 AS | Real estate | 2007 |
| Svein Salvesen AS | Health & social care | 2011 |
| Sweet Naive AS | Financial services | 2018 |
| Symaskinservice AS | Other services | 2025 |
| Syspirasjon AS | Wholesale & retail | 2015 |
| Sysplan AS | Professional & scientific | 2007 |
| Sysplan Holding AS | Professional & scientific | 2007 |
| Sysplan Invest AS | Professional & scientific | 1992 |
| Sytei 818 Holding AS | | 2023 |
| Sønderberg AS | Professional & scientific | 2006 |
| Sønderberg Eiendom AS | | 2012 |
| Søndre Kjerringvik Va-Lag SA | Water & waste | 1994 |
| Sønstebø Gruppen AS | Professional & scientific | 2010 |
| Sørsjyen AS | | 2021 |