| Samfunnshuset Hønefoss AS | Real estate | 2016 |
| Sandberg Hønefoss AS | Wholesale & retail | 2015 |
| Sandums Eiendomstjenester & Mannskapsutleie AS | Administrative & support | 2023 |
| Sandvold Boliger AS | Real estate | 2012 |
| Sandvold Boliger Buskerud AS | Real estate | 2019 |
| Sandvold Eiendommer AS | Real estate | 2018 |
| Sandvold Utvikling AS | Real estate | 2019 |
| Sannan Handelspark Steinkjer AS | Real estate | 2004 |
| Santon AS | Professional & scientific | 2010 |
| Sapu AS | Mining & quarrying | 2005 |
| Sat-Gruppen AS | | 1990 |
| Sateba Norway AS | Manufacturing | 2012 |
| Sateba Steel AS | Manufacturing | 2022 |
| Savjord Holding AS | | 2018 |
| Scan African Flowers Da | Wholesale & retail | 1998 |
| Scancaf AS | Hospitality | 2001 |
| Scandinavian Aerospace Academy AS | Administrative & support | 2008 |
| Scanfast Scandinavian Fastening Norway AS | Wholesale & retail | 2023 |
| Schjongshallen Eiendom AS | Real estate | 2023 |
| Schjongslunden Næring AS | Real estate | 2013 |
| Sebra Øyeklinikk AS | Health & social care | 2025 |
| Secure Work AS | Education | 2013 |
| Sekkemannen AS | Wholesale & retail | 2024 |
| Senneseth Betong & Anlegg AS | Construction | 2015 |
| Sentrum Apotek Hønefoss AS | Wholesale & retail | 2013 |
| Sentrum Eiendom Og Utleie AS | Real estate | 2004 |
| Sentrum Fysioterapi Ans | Health & social care | 1986 |
| Sentrum Stopp AS | Wholesale & retail | 2003 |
| Sentrum Tann AS | Health & social care | 2021 |
| Sentrum Utleie AS | Real estate | 2003 |
| Sentrumslegene Hønefoss AS | Health & social care | 2018 |
| Sesserud AS | Professional & scientific | 1988 |
| Setura AS | Real estate | 1994 |
| Sevlejordet Invest AS | | 2023 |
| SG Holding 1 AS | Wholesale & retail | 2024 |
| SH Tech AS | Professional & scientific | 2017 |
| Shala Bygg AS | Construction | 2016 |
| Showskolen AS | Education | 2012 |
| Shybert Productions AS | Information & communication | 2011 |
| Sieela Invest AS | | 2024 |
| Signatur Invest AS | Real estate | 2026 |
| Sigurd Kittilsland AS | Manufacturing | 1997 |
| Sirani AS | Hospitality | 2025 |
| Siriva AS | | 2019 |
| Sissels Veiledning AS | Other services | 2025 |
| Situ Food AS | Hospitality | 2021 |
| Siv. Ing. Dordi Skjevling AS | Professional & scientific | 2024 |
| Siv.Ing Eivind Pettersen AS | Professional & scientific | 2020 |
| Siv.Ing Nina Rongved AS | Professional & scientific | 2009 |
| Sivilarkitekt Mnal Einar Martin Lundstad AS | Professional & scientific | 2018 |
| Sjakkpass AS | Information & communication | 2024 |
| Skandinavijalastbilar Invest | | 2024 |
| Skandinavijalastbilar Nuf | Wholesale & retail | 2024 |
| Skanse Bygg AS | Construction | 2026 |
| Skaran Øvereng Holding AS | | 2023 |
| Skare Utvikling AS | Professional & scientific | 2023 |
| Skarrud Hytteservice AS | Administrative & support | 2013 |
| Skeidar Hønefoss AS | Wholesale & retail | 2004 |
| Ski Handelsbygg AS | Real estate | 2020 |
| Skigaarden Servering AS | Hospitality | 2019 |
| Skin Stories AS | Health & social care | 2021 |
| Skiptvet Sør AS | Real estate | 2009 |
| Skjersli Småbråten Holding AS | | 2026 |
| Skjærgaard AS | Wholesale & retail | 2019 |
| Sko Deg Hønefoss AS | Wholesale & retail | 2003 |
| Skogal AS | Information & communication | 2008 |
| Skogfaret 9 AS | Real estate | 2020 |
| Skogindustri Holding AS | Manufacturing | 2022 |
| Skogsbilveien Setervad - Vælsvann SA | Real estate | 1942 |
| Skogsbilveien Stubdal-Løvlia | Real estate | 1956 |
| Skogstjernen Familiebarnehage AS | Education | 2012 |
| Skollerud Skogsbilvei SA | Agriculture & fishing | 1938 |
| Sletta Da | Real estate | 1988 |
| Sletta Hønengata AS | Real estate | 2026 |
| Slåtto AS | Professional & scientific | 2022 |
| Smartcraft Norway AS | Information & communication | 2021 |
| Smartcraft Software AS | Information & communication | 2022 |
| Smartcraft Tech AS | Information & communication | 2024 |
| Smartgis AS | Professional & scientific | 2020 |
| Smartsam AS | Information & communication | 2019 |
| Smartshift Robotics AS | Manufacturing | 2007 |
| Smashhh Burger AS | Hospitality | 2025 |
| Smcrt Mgmt 1 AS | | 2022 |
| Smcrt Mgmt 2 AS | | 2024 |
| Smil Renovering AS | Construction | 2025 |
| Smith & Bull AS | Wholesale & retail | 1987 |
| Smith & Bull Trading AS | Wholesale & retail | 1986 |
| SMP Parts Norge AS | Wholesale & retail | 2022 |
| Smspass AS | Other services | 2007 |
| Smurfit Westrock Norge AS | Manufacturing | 1999 |
| Småbarnsforeldrenes Barnehage Ringerike SA | Education | 1992 |
| Snowsilk AS | Wholesale & retail | 2019 |
| Sokna Butikkeiendom AS | Real estate | 2011 |
| Soknedalsveien 17-19 AS | Real estate | 2007 |
| Sola Handelsbygg AS | Real estate | 2010 |
| Solanum AS | Professional & scientific | 1996 |
| Solid Norge Ltd Nuf | Professional & scientific | 2024 |
| Solmøllen Da | Agriculture & fishing | 2009 |
| Sonerud Invest AS | | 2025 |
| Sorgentum AS | Professional & scientific | 2012 |