| Rebel Garden AS | Professional & scientific | 2020 |
| Reftec AS | Construction | 2011 |
| Rehabspesialisten Trondheim AS | Health & social care | 2022 |
| Ren Ilsvika AS | Real estate | 2012 |
| Rent-Gruppen AS | Manufacturing | 2014 |
| Response Nordic AS | Wholesale & retail | 2000 |
| Riis Glass Og Fasade AS | Construction | 1994 |
| Rimol Invest AS | Financial services | 2013 |
| Rimol Miljøpark AS | Manufacturing | 2014 |
| Rise Fire Research AS | Professional & scientific | 2000 |
| Rishaug Renholdsmaskiner AS | Wholesale & retail | 1986 |
| Rishaug Utleie AS | Administrative & support | 2018 |
| Rissa Taxi AS | Transport & logistics | 2026 |
| RJ Regnskap AS | Professional & scientific | 2022 |
| RNT AS | | 2025 |
| Roka Holding AS | Arts & recreation | 2021 |
| Roka Management AS | Professional & scientific | 2022 |
| Roko Rekkverk AS | Wholesale & retail | 2015 |
| Rosted Energi Rosten AS | Wholesale & retail | 2022 |
| Rosten Drift AS | Administrative & support | 2014 |
| RS Auto-Trade AS | Wholesale & retail | 2019 |
| Rune Østgård AS | Financial services | 2013 |
| Rush Trondheim AS | Arts & recreation | 2016 |
| Rust Studio AS | Professional & scientific | 2025 |
| Robertson Nordisk A/S | Construction | 1957 |
| Røhmen Invest AS | Financial services | 2018 |
| Rørlegger 1 AS | Construction | 2026 |
| RØRPARTNER1 AS | Construction | 2013 |
| S. Sangesland AS | Professional & scientific | 2005 |
| S.M.N Holding AS | | 2025 |
| Sabrura Syd AS | Hospitality | 2016 |
| Sagstua Heimdal AS | Financial services | 2005 |
| Sagveien 14 AS | Real estate | 1917 |
| Sagøy Varetransport AS | Transport & logistics | 2025 |
| Sajemo AS | Wholesale & retail | 2024 |
| Sakiro AS | Real estate | 2012 |
| Salix Forbruksvarer Industri AS | Wholesale & retail | 2002 |
| Sandmoen Bed & Breakfast AS | Hospitality | 1976 |
| Sandmoflata 2 AS | Real estate | 2018 |
| Sandvika Panorama AS | Real estate | 2006 |
| Sapeg AS | Manufacturing | 1990 |
| Sapeg Holding AS | Manufacturing | 2015 |
| Sbe Bil AS | Real estate | 2012 |
| Scandi-Tak Eiendom AS | Real estate | 1986 |
| Scandi-Tak Invest AS | Real estate | 2022 |
| Scandisplay AS | Professional & scientific | 2019 |
| Scandtech AS | Administrative & support | 1990 |
| Septemberpia AS | Financial services | 2015 |
| Siem Eiendom AS | | 2008 |
| Sigmasenteret Adm AS | Professional & scientific | 2026 |
| Sigmasenteret Ans | Real estate | 1987 |
| Sigmasenteret AS | Real estate | 2011 |
| Sigmasenteret Eiendom AS | Real estate | 1997 |
| Sintef Ocean Software AS | Information & communication | 2025 |
| Siv.Ing. Danielsen AS | Professional & scientific | 2000 |
| Sivilingeniør a Helsem AS | Professional & scientific | 1986 |
| Sjanse GV AS | Transport & logistics | 2015 |
| Sjøberget Kystnæring AS | Professional & scientific | 2016 |
| Skag AS | Professional & scientific | 2017 |
| Skagan AS | Real estate | 2007 |
| Skagan Utvikling AS | Real estate | 2017 |
| Skalmera AS | Real estate | 2017 |
| Skamfer Holding AS | Real estate | 2025 |
| Skamferhåggån AS | Real estate | 2026 |
| Skanke Stål & Sveis AS | Manufacturing | 1995 |
| Skansen Lydstudio AS | Information & communication | 2019 |
| Skeidar Tiller AS | Wholesale & retail | 2016 |
| Skilt & Print AS | Professional & scientific | 2010 |
| Skin Perfect AS | Other services | 2020 |
| Skolevegen 10 AS | Real estate | 2022 |
| Skuta Barnehage SA | Education | 1989 |
| Skygge Solskjerming AS | Wholesale & retail | 2024 |
| Skyggen Transport AS | Transport & logistics | 2025 |
| Smart Profil Holding AS | Wholesale & retail | 2020 |
| Smart Profil Trondheim AS | Wholesale & retail | 2020 |
| Smart Rekkverk AS | Wholesale & retail | 2019 |
| SMS Interiør AS | Wholesale & retail | 1988 |
| Småbarnsforeldrenes Barnehage Heimdal SA | Education | 1992 |
| Snekkproff AS | Construction | 2024 |
| Snektec AS | | 2026 |
| Snos City Syd AS | Wholesale & retail | 2025 |
| So-Tec Holding AS | Real estate | 2016 |
| Sol 24 AS | Other services | 2011 |
| Solberg Deponi AS | Construction | 2023 |
| Solberg Konsern AS | Professional & scientific | 2015 |
| Soltoppen AS | | 2015 |
| Solva AS | Professional & scientific | 1987 |
| Spex Group AS | Wholesale & retail | 2002 |
| SR Fields AS | | 2023 |
| SRH Eiendom AS | Real estate | 2011 |
| SS Eiendomsinvest AS | Real estate | 2025 |
| Star Wash AS | Other services | 2013 |
| Stasjonsdrift Hepsø AS | Wholesale & retail | 2020 |
| Staurin AS | Real estate | 2014 |
| Steff Invest AS | Financial services | 2005 |
| Steinars Holding AS | Real estate | 2005 |
| Steinkonsult Heimdal AS | Professional & scientific | 1996 |
| Stevik Kløve AS | Health & social care | 2022 |
| Stine Yk Legetjenester AS | Health & social care | 2026 |
| Storebotn 92 AS | Real estate | 1990 |