| Svømmepartner AS | Education | 2018 |
| SW Invest AS | Financial services | 2005 |
| Swan Eiendom AS | Real estate | 2019 |
| Swan-Company AS | Wholesale & retail | 2017 |
| Swea Bygg Ans | Construction | 2009 |
| Sweet Dream AS | Manufacturing | 2025 |
| Sweetgate Norge AS | Manufacturing | 2018 |
| Swenor Consult Ans | Wholesale & retail | 1996 |
| Swissclinical Norway AS | Wholesale & retail | 2007 |
| Swsmalerservice AS | Construction | 2016 |
| Swusj Holding AS | Information & communication | 2024 |
| Swusj Pearl AS | Information & communication | 2025 |
| Swusj Trondheim AS | Information & communication | 2022 |
| Syden Pictures AS | Information & communication | 2021 |
| Sydesign AS | Manufacturing | 2015 |
| Sykepleieartikler Eva Øyangen AS | Wholesale & retail | 1988 |
| Sykkelbua AS | Other services | 2003 |
| Sykkelsentralen AS | Wholesale & retail | 2015 |
| Sykkelxtra AS | Wholesale & retail | 2024 |
| Sylbra Invest AS | Administrative & support | 2011 |
| Sylbra Multiservice AS | Administrative & support | 2022 |
| Syllstokken AS | Construction | 2012 |
| Sylmas AS | | 2021 |
| Symann Tran AS | Manufacturing | 2016 |
| Symbiose Carl Petter Brun AS | Professional & scientific | 1997 |
| Symre Eiendom AS | Real estate | 2021 |
| Symre Invest AS | Real estate | 2015 |
| Syncpoint AS | Information & communication | 2016 |
| Syncron AS | Administrative & support | 1986 |
| Synigo AS | Wholesale & retail | 2010 |
| Synsentrum AS | Wholesale & retail | 1987 |
| Synsentrum Lade AS | Wholesale & retail | 2014 |
| Syrand AS | | 2020 |
| Syrstad Consulting AS | Professional & scientific | 2016 |
| Systemløsning AS | Information & communication | 1989 |
| Systemrevisjon Øst AS | Professional & scientific | 1993 |
| Systemsikring AS | Construction | 1984 |
| Systemvask AS | Administrative & support | 2006 |
| Systor International AS | Information & communication | 2002 |
| Systor Trondheim AS | Information & communication | 1997 |
| Syvert AS | Real estate | 2007 |
| Szechuan Restaurant AS | Hospitality | 2009 |
| Såkorn 1 Midt AS | Financial services | 2023 |
| Såkorninvest Midt-Norge AS | Financial services | 1998 |
| Særimne Holding AS | | 2019 |
| Sæter Holding AS | | 2020 |
| Sæterbakken Utvikling AS | Real estate | 2017 |
| Sæther Eiendomsinvest AS | Real estate | 2024 |
| Sæthers Murerservice AS | Construction | 2001 |
| Sætrom Invest AS | | 1996 |
| Söderberg & Partners Midt-Norge AS | Financial services | 2003 |
| Søberg Eiendom AS | Real estate | 2022 |
| Søbs Invest AS | | 2021 |
| Søbstadvegen 197/971 AS | Real estate | 2021 |
| Søbstadveien 12 Eiendom AS | Real estate | 2007 |
| Søbstadveien 4 AS | Real estate | 2007 |
| Søndre Bygginvest AS | Real estate | 2004 |
| Søndre Gate 12 AS | Hospitality | 2025 |
| Søndre Gate 16 AS | Real estate | 2022 |
| Søndre Gate 19 AS | Real estate | 2005 |
| Søndre Gate 22 AS | Real estate | 2023 |
| Søndre Gate Holdco AS | Real estate | 2023 |
| Søndre GT. 11 AS | Construction | 2014 |
| Søndre GT. 23 AS | Real estate | 1987 |
| Søndre Invest AS | Real estate | 2004 |
| Søndregate 15 AS | Professional & scientific | 2008 |
| Søppelsekk AS | Water & waste | 2016 |
| Søpstad AS | Wholesale & retail | 2016 |
| Sør Hudklinikk AS | Other services | 2020 |
| Sørberg Invest AS | | 2008 |
| Søreng Holding AS | | 2005 |
| Søreng Investering AS | Real estate | 2008 |
| Sørenga 1 AS | Real estate | 2019 |
| Sørenga 11 AS | Real estate | 2013 |
| Sørenga Eiendomsselskap AS | Real estate | 1965 |
| Sørfjordmo Invest AS | | 2023 |
| Sørfrøyveien AS | Real estate | 2025 |
| Sørgjerd AS | Construction | 2025 |
| Sørgjerd Holding AS | | 2025 |
| Sørgård Teknisk Service AS | Wholesale & retail | 2003 |
| Sørkalven AS | Financial services | 2007 |
| Sørlia AS | Professional & scientific | 2017 |
| Sørmarkfjellet AS | Energy | 2018 |
| Søro Holding AS | Real estate | 2006 |
| Sørvik Mur&Flis AS | Construction | 2018 |
| Sørøyåsen Utvikling AS | Real estate | 2021 |
| Søs AS | Professional & scientific | 2005 |
| SØS3 Holding AS | | 2020 |
| Søstrene Ibsen Staven Eiendom Ans | Real estate | 2001 |
| Søstrene Karlsen AS | Hospitality | 2004 |
| Søtberget Bygg AS | Real estate | 2016 |
| T Anderssen Invest AS | | 2024 |
| T Centeret Eiendom AS | Real estate | 2002 |
| T Family AS | Real estate | 2025 |
| T M Dahl Eiendom AS | Real estate | 2001 |
| T Rødsten VVS AS | Construction | 1990 |
| T Sanden Holding AS | | 2026 |
| T Taraldsen Holding AS | | 2026 |
| T Ulvang Invest AS | | 2020 |
| T V Holding AS | | 2005 |