| Ste Eiendom AS | Agriculture & fishing | 2015 |
| Steen & Eftf AS | | 2021 |
| Steinkjøp Da | Wholesale & retail | 2010 |
| Stenshorne AS | Construction | 2008 |
| Stitero AS | Information & communication | 2025 |
| Stix & Trix Production AS | Arts & recreation | 2015 |
| Stordalsveien SA | Real estate | 2021 |
| Storklev AS | Real estate | 2024 |
| Strub Holding AS | | 2025 |
| Studio Eiker AS | Other services | 2025 |
| Sundmoen Handelsområde AS | Real estate | 2021 |
| Svein Espegard AS | | 1990 |
| Svelvik Kombibygg BT2-1 AS | Real estate | 2026 |
| Svelvik Lagerbygg BT2 AS | Real estate | 2026 |
| Svendsen Holding AS | Transport & logistics | 2013 |
| Svendsen Kran Og Transport AS | Transport & logistics | 2013 |
| Skiferkjeller'n ANS | | 1988 |
| Sørby Gartneri AS | Agriculture & fishing | 2004 |
| Sørheim Verdi AS | | 2025 |
| T-Rh AS | Financial services | 2016 |
| T. Thomassen AS | Construction | 2018 |
| T. Thomassen Utleie AS | Real estate | 2015 |
| Tak Galleriet AS | Construction | 2024 |
| Tangen Automasjon AS | Professional & scientific | 2023 |
| Te Hassel Eiendom AS | Real estate | 2022 |
| Terje Bjørgum AS | Manufacturing | 2000 |
| Terje Loe AS | Financial services | 2005 |
| Tommy Warloff Eiendom AS | Real estate | 2008 |
| Tonsenveien 21 AS | Real estate | 2004 |
| Tor Einar Hassel Holding AS | Construction | 2015 |
| Torberg Eiendom AS | Financial services | 2013 |
| Tore Holte AS | Professional & scientific | 2012 |
| Truls Loe Larsen Holding AS | | 2023 |
| Trykk & Tekstil AS | Wholesale & retail | 2025 |
| Twema AS | Financial services | 2005 |
| Tømrermester Frykberg AS | Construction | 2022 |
| Tømrermester Thomas AS | Construction | 2018 |
| Ultra AS | Real estate | 2005 |
| Union Pizza & Grill Avd. Vestfossen AS | Hospitality | 2018 |
| Van Baal Group AS | Professional & scientific | 2025 |
| Van Dijk AS | Administrative & support | 2025 |
| Vectra AS | Real estate | 2025 |
| Vegard Sagvolden AS | Construction | 2016 |
| Vesa Holding AS | | 2026 |
| Vestfjorden Holding AS | | 2015 |
| Vestfold Hyttebygg AS | Real estate | 2021 |
| Vestfossen Fysikalske Institutt AS | Health & social care | 1990 |
| Vestfossen Holding AS | Financial services | 2005 |
| Vestfossen Legesenter AS | Health & social care | 1999 |
| Vestfossen Mek Verksted AS | Manufacturing | 1990 |
| Vestfossen Restaurantdrift AS | Hospitality | 2007 |
| Vestfossen Treningssenter AS | Arts & recreation | 2012 |
| Vestfossen Vannpolering AS | Manufacturing | 2019 |
| Vestsiden Utmarkslag SA | Arts & recreation | 1954 |
| VFS Regnskap AS | Professional & scientific | 2020 |
| Vida La Vida AS | Professional & scientific | 2024 |
| Viken Solskjermingssystemer AS | Wholesale & retail | 2020 |
| Vikente Invest AS | Construction | 2021 |
| Villa Skaar Vestfossen AS | Health & social care | 1997 |
| Vintage Electric Audio Da | Wholesale & retail | 2009 |
| W Bygg AS | Construction | 2017 |
| W Prosjekt AS | Construction | 2019 |
| W Utleie AS | Construction | 2017 |
| Warloff Fjellsprenging AS | Construction | 2011 |
| Warloff Holding AS | | 2024 |
| Wash Group Holding AS | Other services | 2021 |
| Weman Holding AS | Construction | 2017 |
| Wikheim & Eliassen Sport AS | Wholesale & retail | 2023 |
| Woldstad AS | Financial services | 2017 |
| Xcamp AS | Wholesale & retail | 2019 |
| Xela Invest AS | Financial services | 2007 |
| Yndesdal Transport AS | Transport & logistics | 2022 |
| Yte AS | Real estate | 2019 |
| Zodium AS | Wholesale & retail | 2022 |
| Økoinvest Eiker AS | Professional & scientific | 2015 |