| Solid Familiekompetanse AS | Health & social care | 2023 |
| Solid Studio AS | Professional & scientific | 2021 |
| Solid Trading AS | Wholesale & retail | 2017 |
| Solo Tekstil AS | Financial services | 1970 |
| Solsiden Moss AS | Hospitality | 2017 |
| Solveien Bil AS | Other services | 1988 |
| Solvendt Bolig AS | Real estate | 2024 |
| Soma Sko AS | Wholesale & retail | 1976 |
| Somnium Holding AS | | 2019 |
| Son Marine Eiendom AS | Real estate | 2013 |
| Son Marine Holding AS | Transport & logistics | 2013 |
| Son Marine Service AS | Transport & logistics | 2013 |
| Sonber Holding AS | | 2023 |
| Sonconsult AS | Professional & scientific | 2012 |
| Sonken AS | Real estate | 2008 |
| Soria Consulting AS | Professional & scientific | 2025 |
| Sortland Fasadevask AS | Professional & scientific | 2009 |
| Sosa Holding AS | | 2020 |
| Sparebank 1 Østfold Akershus | Financial services | 1971 |
| SPB Invest AS | | 2021 |
| Specup AS | Wholesale & retail | 2023 |
| Speed Group AS | Transport & logistics | 2025 |
| Speed Transport Management AS | Transport & logistics | 2025 |
| Speider-Sport AS | Wholesale & retail | 2012 |
| Spenst Moss AS | Arts & recreation | 2005 |
| Spenst Norge AS | Arts & recreation | 2011 |
| Spesialistlege AS | Health & social care | 2020 |
| Spetz Eiendom AS | Real estate | 2015 |
| Spetz Holding AS | Manufacturing | 2015 |
| Spino AS | Financial services | 2016 |
| Spirhed AS | Information & communication | 2023 |
| Spirhed Group AS | Information & communication | 2023 |
| Spirhed Norway AS | Information & communication | 2009 |
| Spirox AS | Health & social care | 2025 |
| Sponsorinvest Ans | Administrative & support | 2000 |
| Spontane Dråper AS | Wholesale & retail | 2021 |
| Sporenstrek Reklame AS | Professional & scientific | 1997 |
| Sports Marketing AS | Wholesale & retail | 1993 |
| Sports Nutrition Norge AS | Wholesale & retail | 2021 |
| Spraying Systems Norge AS | Wholesale & retail | 2001 |
| Språkviter Karine Stjernholm AS | Education | 2023 |
| SR Turbuss AS | Transport & logistics | 2019 |
| SRD Invest AS | Real estate | 2008 |
| SRM & Co Invest AS | Real estate | 2022 |
| SRW AS | Professional & scientific | 2022 |
| SRW Eiendom AS | Real estate | 2024 |
| SRW Management AS | Professional & scientific | 2023 |
| SRW Yachting AS | Wholesale & retail | 2024 |
| Ss-Birkeland II AS | Financial services | 2008 |
| ST! Holding AS | Real estate | 2016 |
| Stadion AS | Wholesale & retail | 1989 |
| Stadion Regnskap AS | Professional & scientific | 2013 |
| Stall Corner AS | Wholesale & retail | 2026 |
| Stall Kubberød AS | Agriculture & fishing | 1984 |
| Standard Sport AS | Wholesale & retail | 1992 |
| Standard Sykkelservice AS | Other services | 2000 |
| Stas Moss AS | Wholesale & retail | 2024 |
| Stasjonsveien 14 Rygge AS | Real estate | 2017 |
| Stavangerhus AS | Real estate | 2017 |
| Steinhaugen & Co Ans | Manufacturing | 1989 |
| Steinsviks Regnskapskontor Ans | Professional & scientific | 1988 |
| Stellanor Limited Nuf | Financial services | 2006 |
| Stena Stål AS | Wholesale & retail | 1994 |
| Stenberg Osteopati AS | Health & social care | 2021 |
| Stengata Auto AS | Other services | 2021 |
| Stian Arnesen AS | Real estate | 2019 |
| Stian Westbye Holding AS | | 2022 |
| Stida Eiendom AS | Real estate | 1993 |
| Stiegelmeyer AS | Wholesale & retail | 2026 |
| Stiftelsen Zum Landhaus | | 1998 |
| Stig K. Lunde AS | Financial services | 2005 |
| Stimlar Holding AS | Real estate | 2022 |
| Stimme AS | | 2019 |
| Stine AS | Real estate | 2023 |
| Stinn Brakke Holding AS | Hospitality | 2018 |
| Stirling Holding AS | Real estate | 2006 |
| STJ Fokus AS | Wholesale & retail | 2026 |
| Stocktella AS | Professional & scientific | 2020 |
| Stol På Tuva AS | Health & social care | 2025 |
| Stordahl Eiendom AS | Real estate | 2007 |
| Stordahl Musikk AS | Wholesale & retail | 1981 |
| Storebaug Hotell Og Kro AS | Hospitality | 2017 |
| Storesund Holding AS | Real estate | 2016 |
| Storgata 6 Eiendom Moss AS | Real estate | 2024 |
| Storgaten 6 Rakkestad Næring AS | Real estate | 2024 |
| STORGT-1 AS | Real estate | 2008 |
| Storm AS | Professional & scientific | 1976 |
| Storm Eiendom Moss AS | Real estate | 2021 |
| Storm Elektro Moss AS | Construction | 2002 |
| Storm VVS AS | Construction | 2002 |
| Storm VVS Holding AS | Construction | 2008 |
| Storvik & Bjerkeng AS | Professional & scientific | 2025 |
| Storybold AS | Professional & scientific | 1991 |
| Strax Brun AS | Other services | 2024 |
| Strax Frisør AS | Other services | 2024 |
| Strax Invest AS | Real estate | 2024 |
| Street Bikes AS | Wholesale & retail | 2024 |
| Strongroom AS | Professional & scientific | 2017 |
| Strupene Da | Information & communication | 2013 |
| Strømme AS | | 2021 |