| Sel Holding AS | | 2012 |
| Select Bemanning AS | Administrative & support | 2016 |
| Semu Eiendom AS | Real estate | 2019 |
| SG Anleggspark AS | Real estate | 2013 |
| SG Deponi AS | Mining & quarrying | 2007 |
| SG Entreprenør AS | Construction | 2011 |
| Shankia AS | Construction | 2005 |
| Siv Ing Arne Vaslag AS | Professional & scientific | 1988 |
| Sjåførtjenester Trøndelag Da | Administrative & support | 2007 |
| Skagen Smie & Hovslageri AS | Agriculture & fishing | 2015 |
| Skare Solutions AS | Professional & scientific | 2025 |
| Skarsem & Jakobsen Maskinlag Da | Agriculture & fishing | 2009 |
| Skibnes Eiendom AS | Real estate | 1989 |
| Skibnes Invest AS | Real estate | 2020 |
| Skjerdingstad Næringspark AS | Real estate | 2015 |
| Skjetne Maskin AS | Wholesale & retail | 2018 |
| Skuteng Invest AS | | 2020 |
| Skånøy Eiendomsutvikling AS | Real estate | 2017 |
| Sliwa Invest AS | Manufacturing | 2022 |
| Slåentunet AS | Real estate | 2017 |
| Smak Og Opplev Melhus SA | Other services | 2019 |
| Snø Interiør AS | Professional & scientific | 2021 |
| Snøfugl Forlag AS | Information & communication | 1995 |
| Solberg Eiendom AS | Real estate | 2001 |
| Solseth AS | Financial services | 2006 |
| Soplimgrenda Avløpslag SA | Water & waste | 2021 |
| Spencer Elektro AS | Financial services | 2005 |
| Staas AS | Manufacturing | 2005 |
| Staas Eiendom AS | Real estate | 2014 |
| Stage Dolls Da | Arts & recreation | 2004 |
| Stall Øysand AS | Arts & recreation | 1994 |
| Stasjonsdrift Jonas Hepsø AS | Wholesale & retail | 2025 |
| Stav Og Schive Eiendom AS | Real estate | 2019 |
| Stepanko AS | Transport & logistics | 2025 |
| Stetind Advisory AS | Professional & scientific | 2026 |
| Sti Eiendom AS | Real estate | 2026 |
| Stoff Og Sting Da | Wholesale & retail | 1990 |
| Stokkgjerdsvegen 8-20 SA | Construction | 2022 |
| Storm Bolig AS | Construction | 2021 |
| Storsand Holding AS | Real estate | 2005 |
| Storvold Holding AS | | 2026 |
| Strandheimen Gjestehus AS | Hospitality | 2017 |
| Studio H & M Frisør AS | Other services | 2000 |
| Stål Og Byggtjenester AS | Construction | 2019 |
| Sundgot Holding AS | | 2022 |
| Sundset Jacobsen Holding AS | | 2023 |
| Supernerds AS | Wholesale & retail | 2021 |
| Svang AS | Real estate | 2023 |
| Svartåsmyra AS | | 2026 |
| Svinsås Auto Melhus AS | Wholesale & retail | 1995 |
| Søberg Midtre AS | Real estate | 2018 |
| Sør-Trøndelag Malerservice Da | Construction | 2008 |
| Sørstu Hundehotell AS | Administrative & support | 1988 |
| T. Evensen Holding AS | | 2023 |
| T. Rønning AS | Construction | 2016 |
| T.Skånøy Transport AS | Transport & logistics | 2013 |
| Tacamera AS | Wholesale & retail | 2016 |
| Tad Gruppen AS | Construction | 2023 |
| Tad Rørservice AS | Construction | 2022 |
| Tak & Flisleggeren AS | Construction | 2011 |
| Takxperten AS | Construction | 2017 |
| Tannlege B. Bakken AS | Health & social care | 2005 |
| Tannlege Benjaminsen AS | Health & social care | 2006 |
| Tannlege Årseth AS | Health & social care | 2008 |
| TBD Holding AS | Real estate | 2021 |
| TBS Optimal AS | Administrative & support | 2010 |
| Tbygg AS | Professional & scientific | 2023 |
| Tebe Sport AS | Arts & recreation | 2005 |
| Tech AS | Other services | 2019 |
| Tetro Holding AS | | 2023 |
| TFS Blikk Og Fasade AS | Construction | 2023 |
| TFS Entreprenør AS | Construction | 2013 |
| TFS Holding AS | Real estate | 2018 |
| TFS Tak Og Membran AS | Construction | 2023 |
| Thamshavn Næringspark AS | Real estate | 2021 |
| Thorgård Idrettsentreprenør AS | Professional & scientific | 2023 |
| Tjora Invest AS | Financial services | 2014 |
| TLM Invest AS | Financial services | 2020 |
| Tokaa Holding AS | Financial services | 2014 |
| Tomas Eiendom AS | Real estate | 2013 |
| Tomas Eiendom II AS | Real estate | 2022 |
| Toppclair Invest AS | | 2017 |
| Topptrener.No AS | Education | 2014 |
| Tores VVS AS | Construction | 2011 |
| Torgrim Daling AS | Education | 2024 |
| Torini TRD Da | Wholesale & retail | 2026 |
| Totalmaskin AS | Construction | 2011 |
| Totalrens AS | Administrative & support | 2025 |
| TRB Bolig AS | Real estate | 2022 |
| Trebetong AS | Construction | 2018 |
| Trebetong Entreprenør AS | Construction | 1989 |
| Trebetong Prosjekt AS | Real estate | 2018 |
| Tribewear Distributions Da | Wholesale & retail | 2002 |
| Trondheim Steinindustri AS | Manufacturing | 1997 |
| Trondheim Stål AS | Manufacturing | 1989 |
| Trondhjem Montering Og Vaktmesterservice AS | Administrative & support | 2022 |
| Tryggest Handel AS | Wholesale & retail | 2021 |
| Trøndelag Hesteklinikk AS | Professional & scientific | 2018 |
| Trøndelag Sankeri AS | Wholesale & retail | 2019 |
| Trøndelag Service AS | Professional & scientific | 2019 |