| Skog & Hage Nittedal AS | Wholesale & retail | 1990 |
| Skogstad Konsult AS | Real estate | 2015 |
| Skådinn Invest AS | | 2025 |
| Skålnes Holding AS | | 2023 |
| Sletten Forvaltning AS | | 2026 |
| Smed Tjelle Holding AS | Manufacturing | 2022 |
| Smådyrklinikken I Nittedal AS | Professional & scientific | 2025 |
| Sol-Tun AS | Real estate | 2005 |
| Solaas Consulting AS | Professional & scientific | 2024 |
| Solbu Bygg AS | Construction | 2023 |
| Solli Holdings AS | | 2025 |
| Soppbutikken AS | Wholesale & retail | 2025 |
| Sorgendal Holding AS | | 2026 |
| Sori Wonder AS | Wholesale & retail | 2026 |
| Spenstig AS | Information & communication | 2005 |
| Sporfi AS | | 1990 |
| Sportplus AS | Wholesale & retail | 2021 |
| Sta AS | Construction | 2013 |
| Sta-Rent AS | Administrative & support | 2022 |
| Starholmen AS | Professional & scientific | 2015 |
| Stasjonsveien 70 AS | | 1994 |
| Stavil Invest AS | Health & social care | 2021 |
| Steinrøysa Andelsbarnehage SA | Education | 1998 |
| Storgata 1 Gjøvik AS | Real estate | 2009 |
| Storgata 10 AS | Real estate | 2006 |
| Storgata 3 Gjøvik AS | Real estate | 2006 |
| Storgata 8 Gjøvik AS | Real estate | 2007 |
| Storheim Invest AS | Financial services | 2018 |
| Storhytta Nuf | Real estate | 2009 |
| Storhytten AS | Real estate | 2026 |
| Storøy Ventures AS | | 2026 |
| Streamstew Technologies AS | Information & communication | 2018 |
| Stubben Barnehage SA | Education | 2002 |
| Studio Krokan AS | Professional & scientific | 2022 |
| Stålkapital AS | | 2026 |
| Sunnmøre Toppturer AS | Hospitality | 2026 |
| Sushi-Jentene Nittedal AS | Hospitality | 2026 |
| Svein Arne Thrana AS | Education | 2012 |
| Sveis Og Vegsikring AS | Manufacturing | 1996 |
| Sverris Holding AS | Health & social care | 2023 |
| Sykkel- Og Skispesialisten AS | Wholesale & retail | 2018 |
| Synnfjellhytta AS | Construction | 2018 |
| Søgaard Ventures AS | | 2023 |
| Sørliveien Barnehage SA | Education | 1992 |
| T. Pettersen Holding AS | Financial services | 2010 |
| T.R. Marthinsen Holding AS | | 2022 |
| Talla AS | Information & communication | 2026 |
| Tally Boon AS | Professional & scientific | 2023 |
| Tangen Brygge AS | Arts & recreation | 2016 |
| Tannlegevakten Oslo AS | Health & social care | 2005 |
| Tcprofil AS | Wholesale & retail | 2022 |
| TCT Norge AS | Professional & scientific | 2024 |
| Teknisk Entreprenør AS | Professional & scientific | 2013 |
| Tekniske Konsulenttjenester AS | Transport & logistics | 2017 |
| Tekstsnekker Gjelsvik AS | Arts & recreation | 2022 |
| Therezas Beautyroom AS | Other services | 2020 |
| Thor AS | | 2020 |
| Thrana HR AS | Education | 2013 |
| Tilta AS | Real estate | 2017 |
| Tinkll AS | | 2025 |
| Tivar AS | Professional & scientific | 2019 |
| Tordenskjoldsgt 11 AS | Real estate | 2013 |
| Torjuul Direct AS | Financial services | 2012 |
| Torunn Fallet Jensen Holding AS | | 2022 |
| Transport Drift Og Vedlikehold AS | Construction | 2017 |
| Troll Invest AS | Professional & scientific | 1999 |
| Tromo AS | Wholesale & retail | 2018 |
| Troya Invest AS | Real estate | 2005 |
| Tyholdt Holding AS | | 2022 |
| Tøien Forretningsbygg AS | Real estate | 2014 |
| Tømrermester Anders Ellefsen AS | Construction | 2005 |
| Ukab Eiendom AS | Real estate | 2007 |
| Ullern Torvstrøfabrik AS | Mining & quarrying | 1939 |
| Ulvetind AS | | 2026 |
| Utheim Grendehus SA | Real estate | 1995 |
| Utviklingstrappa AS | Education | 2022 |
| V. Stavdal Holding AS | Financial services | 2015 |
| Veggbilder AS | Wholesale & retail | 2017 |
| Vento Brands AS | Professional & scientific | 2026 |
| Veslehagan Invest AS | | 2023 |
| Vestvendt Kapital AS | | 2020 |
| Veterinær Marie Bårli AS | Professional & scientific | 2020 |
| Vettir Invest AS | | 2020 |
| Viligner AS | Wholesale & retail | 2023 |
| Vilmart AS | Real estate | 2007 |
| Vilt Brenneri AS | Arts & recreation | 2026 |
| Vinjerui Holding AS | | 2025 |
| Vinju Aarskog AS | Real estate | 2005 |
| Voss Øksnevad Holding AS | | 2021 |
| Værekraft AS | Health & social care | 2022 |
| Wallentin Eiendom AS | Real estate | 2025 |
| Wassbakk Consulting AS | Professional & scientific | 2023 |
| Westgaardskan AS | | 2018 |
| Winspace Norge AS | Wholesale & retail | 2026 |
| Wunjo Sports AS | Wholesale & retail | 2017 |
| Yebo AS | Professional & scientific | 2021 |
| Yusuf Capital & Partners AS | Professional & scientific | 2019 |
| Åneby Senter AS | Real estate | 2018 |
| Østkraft Ans | Energy | 1997 |
| Øståsen Grunneierlag I Nittedal SA | Agriculture & fishing | 1952 |