| Solheimveien 50 AS | Real estate | 2026 |
| Solheimveien 7 AS | Real estate | 2006 |
| Solid Bygg Og VVS AS | Construction | 2025 |
| Solid Eiendomsutvikling AS | Real estate | 2020 |
| Solid Rekruttering AS | Administrative & support | 2025 |
| Solsikken Blomster AS | Wholesale & retail | 2002 |
| SPORTY60 AS | Education | 2022 |
| SR Joker AS | Wholesale & retail | 2026 |
| Staggioni Fashion Da | Wholesale & retail | 2005 |
| Star Autoco Bil AS | Wholesale & retail | 2024 |
| Star Autoco Eiendom AS | Real estate | 1985 |
| Star Autoco Holding AS | Real estate | 2005 |
| Star Palace AS | Real estate | 2018 |
| Stark Electric AS | Manufacturing | 2018 |
| Startech AS | Professional & scientific | 2015 |
| Starveien AS | Real estate | 2019 |
| Stasjonsdrift Peroti AS | Wholesale & retail | 2019 |
| Static Edge AS | Other services | 2025 |
| Stenerud Byggservice AS | Construction | 2002 |
| Stenerud Rørservice AS | Construction | 2024 |
| Sterling Holding AS | | 2019 |
| Sterling Property AS | Real estate | 2026 |
| Stevnelegene Da | Health & social care | 2012 |
| Stigbo AS | Wholesale & retail | 2016 |
| Stonks Invest AS | Information & communication | 2022 |
| Storgata 148 AS | Real estate | 2006 |
| Storgata Eiendom Lillehammer AS | Real estate | 2006 |
| STORM1 Holding AS | | 2024 |
| Struksnes Invest AS | Financial services | 2014 |
| Strømmen Barnelegesenter AS | Health & social care | 1989 |
| Stø Entreprenør AS | Construction | 2018 |
| Støle Invest AS | Professional & scientific | 2022 |
| Subway Metro AS | Hospitality | 2026 |
| Sudacat AS | Real estate | 2021 |
| Sugar Systue AS | Other services | 2023 |
| Sundli Holding AS | | 2025 |
| Sundsby Eiendom AS | Real estate | 2011 |
| Suong AS | Hospitality | 2012 |
| Super Connect Ans | Manufacturing | 1991 |
| Supervisjon AS | Professional & scientific | 2025 |
| Svanedamsveien 6-8 AS | Real estate | 2006 |
| SVM Invest AS | | 2022 |
| Swa AS | | 2016 |
| Sykehuspersonalets Velferdslag SA | Wholesale & retail | 1969 |
| Sykkelopplevelser AS | Wholesale & retail | 2006 |
| Syotno AS | Information & communication | 2023 |
| Sødal Fysioterapi AS | Health & social care | 2025 |
| Søppelbud AS | Water & waste | 2018 |
| Sørlie Mining Invest AS | Mining & quarrying | 2015 |
| Sørlifeltets Fellesområder SA | Real estate | 1963 |
| Sørlikroa AS | Hospitality | 2026 |
| Sørumsand Handelspark AS | Real estate | 2024 |
| T Gran Eiendomsselskap AS | Real estate | 1959 |
| T. Berentzen Holding AS | | 2023 |
| T/N Eksport AS | Wholesale & retail | 2018 |
| Ta Knausen AS | Financial services | 2005 |
| Tabify AS | Information & communication | 2025 |
| Tannhelsesenteret Lørenskog AS | Health & social care | 2000 |
| Tannlege Kjeksrud AS | Health & social care | 2018 |
| Tara Holding AS | Professional & scientific | 2018 |
| Tauler Bygg AS | Construction | 2022 |
| Tauler Holding AS | Construction | 2021 |
| Tauler Rør AS | Construction | 2021 |
| Taz Trading AS | Wholesale & retail | 2016 |
| TB Montasjeservice AS | Construction | 2023 |
| Tcbil AS | | 2004 |
| Techtemp AS | Administrative & support | 2006 |
| Tecodian AS | Wholesale & retail | 2026 |
| Tekka Byggeadministrasjon AS | Professional & scientific | 2020 |
| Tekka Holding AS | Professional & scientific | 2020 |
| Telekiosken Metro AS | Wholesale & retail | 2003 |
| Tellzy AS | Information & communication | 2025 |
| Tendent AS | Transport & logistics | 2023 |
| Teo Maskin AS | Construction | 2015 |
| Tessta Electronic AS | Construction | 1994 |
| TFC Rør AS | Construction | 2019 |
| Tfc-Technical Fire Consulting AS | Professional & scientific | 2016 |
| Thai Therapy AS | Health & social care | 2025 |
| The Barber Club Lørenskog Da | Other services | 2024 |
| The Coconut AS | Other services | 2023 |
| The Go to Market Company AS | Professional & scientific | 2020 |
| The Print House Norway Da | Manufacturing | 2017 |
| The Swan by Tiril AS | Manufacturing | 2025 |
| Thimax Invest AS | | 2021 |
| Thomas Renhold AS | Administrative & support | 1999 |
| Thunir Holding AS | Real estate | 2022 |
| Tian Helse Øst AS | Health & social care | 2023 |
| Tide Holding AS | Real estate | 2014 |
| Tide Sea AS | | 2025 |
| Tilfreds AS | Hospitality | 2022 |
| Titan Renhold AS | Administrative & support | 2021 |
| Tivi Eiendom AS | Construction | 1984 |
| TK Tømrerteam Da | Construction | 2005 |
| TLS Transport AS | Transport & logistics | 2018 |
| Tlsi AS | Financial services | 2012 |
| TMZ AS | Financial services | 2006 |
| To Tømrermenn AS | Construction | 2006 |
| Todu Holding AS | | 2019 |
| Tom Hagen Eiendom AS | Real estate | 1978 |
| Tonje N. Eliassen AS | Other services | 2024 |