| Sandmo Invest AS | Real estate | 2017 |
| Saxo Eiendom AS | Real estate | 2010 |
| Scistron AS | Professional & scientific | 2013 |
| Secunda AS | | 2022 |
| Segtnan Kunnskapsutvikling AS | Education | 2007 |
| Sende Samdrift Da | Agriculture & fishing | 2007 |
| Sentrum Regnskap AS | Professional & scientific | 2002 |
| SH Teknikk AS | Professional & scientific | 2013 |
| Shmil Transport AS | Transport & logistics | 2008 |
| Siljeholmen Eiendom AS | Financial services | 2005 |
| Simen Moss Holding AS | | 2017 |
| Simon Almås Holding AS | | 2025 |
| Sinus Mosjøen AS | Construction | 2010 |
| Sjåtoften Holding AS | Real estate | 2020 |
| Sjøgata 15 AS | Real estate | 2023 |
| Sjøgata 23 AS | Real estate | 2015 |
| Sjøgata Live AS | Arts & recreation | 2012 |
| Sjøgata Medical Da | Health & social care | 2009 |
| Sjøsiden Spiseri AS | Hospitality | 2024 |
| Skala Invest AS | Professional & scientific | 2021 |
| Skaland Eiendom AS | Real estate | 2006 |
| Skaland Naturbarnehage AS | Education | 2006 |
| Skaland Terassehus AS | Professional & scientific | 2009 |
| Skalandsbukta Grunneierlag SA | Real estate | 2011 |
| Skillup Network AS | Education | 2021 |
| Skjerva Eiendom AS | Real estate | 1995 |
| Skjervgata 8 Eiendom AS | Real estate | 1998 |
| Skjervstad Holding AS | | 2025 |
| Skjønnhetspartner AS | Other services | 2017 |
| Skog Eiendom AS | Real estate | 2021 |
| Skog Industries AS | Professional & scientific | 2021 |
| Skogfjell AS | Wholesale & retail | 2026 |
| Skogfjell Holding AS | | 2026 |
| Skul Svendsveg 6 AS | Real estate | 2021 |
| Slotterøy Invest AS | Health & social care | 2023 |
| Smalås Eiendom AS | Real estate | 2009 |
| Smisto Kraft AS | Energy | 2015 |
| SN Gruppen AS | Real estate | 2013 |
| Snbh Invest AS | | 2023 |
| Soldyr Invest AS | | 2024 |
| Solvang & Aanes AS | Real estate | 2013 |
| Sort Eiendom AS | Real estate | 2019 |
| Sport 1 Flokkmann Mosjøen AS | Wholesale & retail | 2022 |
| Sport 1 Mosjøen AS | Wholesale & retail | 1983 |
| Stasjonsdrift Finholt AS | Wholesale & retail | 2017 |
| Stasjonsdrift Mosjøen AS | Wholesale & retail | 2026 |
| Steinkjer Marina AS | Arts & recreation | 2009 |
| Stensland Invest AS | Wholesale & retail | 2020 |
| Stensland Optikk AS | Wholesale & retail | 2020 |
| Stenvall Eiendomsutvikling AS | Real estate | 2022 |
| Stian Forsmo AS | | 2023 |
| Stiberget Eiendom AS | Real estate | 2019 |
| Stil Holding AS | | 2025 |
| Stokmo Invest AS | | 2020 |
| Storsand AS | Real estate | 2026 |
| Storvik Mosjøen AS | Manufacturing | 2022 |
| Straum Media AS | Information & communication | 2020 |
| Strofe Holding AS | | 2025 |
| Studio Akm AS | Professional & scientific | 2009 |
| Studio-Nord AS | Information & communication | 2021 |
| Studium AS | Other services | 2026 |
| Subseacomm AS | Professional & scientific | 2013 |
| Sundri Holding AS | | 2022 |
| Super Eiendom AS | Real estate | 2006 |
| Svebakk Drift 365 AS | Administrative & support | 2026 |
| Svein Bogfjelldal AS | Construction | 2016 |
| Svevia Norge AS | Construction | 2011 |
| Svst Invest AS | Financial services | 2023 |
| Sykehuskiosken AS | Wholesale & retail | 2000 |
| System Hall AS | Construction | 1998 |
| Søfting Sandblåse Service AS | Manufacturing | 2019 |
| Sørensen-Invest AS | Hospitality | 2021 |
| Sørum Silketrykk AS | Manufacturing | 2005 |
| T G Bygg Og Eiendom AS | Construction | 2015 |
| T&L Invest AS | Real estate | 2015 |
| T. Solem Holding AS | Financial services | 2014 |
| Takproffen AS | Construction | 2002 |
| Tan Consulting AS | Professional & scientific | 2021 |
| Tannlege Bente Willassen AS | Health & social care | 2012 |
| Tannlege Hoff Petersen AS | Health & social care | 1986 |
| Tannlege Ivar Kvitnes AS | Health & social care | 2005 |
| Tannlege Slotterøy AS | Health & social care | 2018 |
| Tapperiet Film Og VFX AS | Information & communication | 2012 |
| Tat Invest AS | | 2021 |
| Team Helgeland AS | Hospitality | 1999 |
| Ted Eiendom AS | Real estate | 2010 |
| Tejak Holding AS | | 2026 |
| Teknikk Og Prosjekt AS | Professional & scientific | 2006 |
| Tempelhaugen Eiendom AS | Real estate | 2019 |
| Termas AS | Administrative & support | 2025 |
| Testpartner Holding AS | Professional & scientific | 2023 |
| Testpartner Invest AS | Professional & scientific | 2024 |
| THB Holding AS | Information & communication | 2013 |
| Thecompany AS | Construction | 2018 |
| Thojar AS | Professional & scientific | 2013 |
| Thomas Jakobsen Holding AS | | 2023 |
| Thomm AS | Education | 2025 |
| Thomsen Invest AS | | 2022 |
| Thrana Klinikken AS | Health & social care | 2019 |
| TJ7 Prosjekt AS | Professional & scientific | 2023 |