| Storevigen AS | Real estate | 1997 |
| Storgata 111 AS | Real estate | 2014 |
| Storgata 116 Eiendom AS | Real estate | 2015 |
| Storgata 120 AS | Real estate | 2025 |
| Storgata 128 AS | Real estate | 2019 |
| Storgata 18 Harstad AS | Real estate | 2024 |
| Storgata 2 Harstad AS | | 2024 |
| Storgata 61-63 AS | Real estate | 2019 |
| Storgata 69 AS | Real estate | 2023 |
| Storgata 70 Tromsø AS | Real estate | 2023 |
| Storgata 9 Harstad AS | | 2024 |
| Storgata 92 AS | Real estate | 2008 |
| Storgata 92 Tromsø AS | Real estate | 2021 |
| Storgata Invest AS | Real estate | 2007 |
| Storgatbakken Dagligvarer AS | Wholesale & retail | 2019 |
| Storgaten 85 AS | Real estate | 1986 |
| Storgt. 33 AS | Real estate | 2019 |
| Storgt. 78 - Gården AS | Real estate | 2023 |
| STORGT.88 AS | Real estate | 1991 |
| Storhaug + Partnere AS | Real estate | 2023 |
| Storhaugen 1 AS | Real estate | 2025 |
| Storhaugen AS | Real estate | 2016 |
| Storheia 1 AS | Real estate | 2006 |
| Storm Eiendomsforvaltning AS | Real estate | 2024 |
| Storm PM Invest AS | | 1995 |
| Stormcam AS | Professional & scientific | 2014 |
| Stormgard Holding AS | Real estate | 2017 |
| Stormo Boliger AS | Real estate | 2013 |
| Stormo Eiendom AS | Real estate | 1997 |
| Stormsol AS | | 2026 |
| Storslett Invest AS | Administrative & support | 2021 |
| Stortorget 3 AS | Real estate | 2012 |
| Stortorget 4 AS | Real estate | 2019 |
| Storvoll Holding AS | | 2025 |
| Strand Manuellterapi AS | Health & social care | 2013 |
| Strand Pizza AS | Hospitality | 2017 |
| Strandby Berge Holding AS | Real estate | 2024 |
| Strandgata 22. AS | Arts & recreation | 2009 |
| Strandgata 30 AS | Real estate | 2010 |
| Strandgata 41 AS | Real estate | 2022 |
| Strandgata 5-9 AS | Real estate | 2022 |
| Strandgata Eiendom AS | Real estate | 1998 |
| Strandkanten Bydel SA | Real estate | 2010 |
| Strandkanten Fus Barnehage AS | Education | 2019 |
| Strandtorget 1 AS | Real estate | 2011 |
| Strandtorget 5 Eiendom AS | Wholesale & retail | 2015 |
| Strandtorget Tannklinikk AS | Health & social care | 2019 |
| Strandvegen 108 Tromsø AS | Real estate | 1917 |
| Strandvegen 182 AS | Real estate | 2025 |
| Strandvegen 8 Eiendom AS | Real estate | 2020 |
| Strandvegen 8 Holding AS | Real estate | 2025 |
| Strandvegen Næring AS | Real estate | 2018 |
| Straterio AS | Information & communication | 2017 |
| Straumsnes Lund Holding AS | | 2023 |
| Strax Gladlax AS | Health & social care | 2020 |
| Strekken AS | | 2017 |
| Strømmesen Invest AS | | 2021 |
| Strømnes Invest AS | | 2015 |
| Strømseng Invest AS | Real estate | 2016 |
| Stubbeng Consulting AS | Administrative & support | 2020 |
| Studio 5 AS | Other services | 2016 |
| Studio Pilates Trening Og Fysioterapi AS | Arts & recreation | 2008 |
| Studio Steinar Berg-Olsen AS | Wholesale & retail | 2022 |
| Style Me Symy AS | Other services | 2025 |
| Styrmann AS | Information & communication | 2026 |
| Stålvikbotn AS | Real estate | 2019 |
| Stær AS | Information & communication | 2022 |
| Stærk Holding AS | Professional & scientific | 2008 |
| Støa 3 AS | Real estate | 2026 |
| Subsea Toolpool Nord AS | Administrative & support | 2012 |
| Sulland Tromsø AS | Other services | 1991 |
| Sumo Vervet AS | Hospitality | 2021 |
| Sun Invest AS | Real estate | 2005 |
| Sunna Invest AS | Construction | 2014 |
| Sunny Capital Investment AS | | 2026 |
| Sunset Grill AS | Financial services | 2016 |
| Superlys AS | Professional & scientific | 2021 |
| Superposition AS | | 2021 |
| Supersterk AS | | 2026 |
| Supersub AS | Professional & scientific | 2023 |
| Suvi AS | Hospitality | 2014 |
| Svartnes Vannverk SA | Water & waste | 1979 |
| Sveivia Consulting AS | Professional & scientific | 2014 |
| Svellingen Net AS | Information & communication | 2021 |
| Svermeriet Kafe Og Redesign AS | Hospitality | 2018 |
| Sweet Heart AS | Wholesale & retail | 1995 |
| Sylfrekt Orkester Da | Arts & recreation | 2021 |
| Symaskin Og Søm AS | Wholesale & retail | 2016 |
| Synova AS | Energy | 2025 |
| Synssenteret Jekta AS | Wholesale & retail | 2005 |
| Syntos Da | Professional & scientific | 1995 |
| SÁL AS | Information & communication | 2026 |
| Sånn AS | Hospitality | 2015 |
| Sølvfest Holding AS | Real estate | 2021 |
| Sømhovd AS | Other services | 2025 |
| Sømloftet Ans | Manufacturing | 1994 |
| Søndre Tollbodgate 1 AS | Real estate | 2005 |
| Sør-By Prosjektet SA | Real estate | 2014 |
| Sørbotn Grunneierlag | Real estate | 1979 |
| Sørbyen Legesenter Tromsø AS | Health & social care | 2022 |