| Mt-Hytter & Hus AS | Real estate | 2020 |
| Newprobe AS | Wholesale & retail | 2020 |
| Nilsen Hytteutvikling AS | Construction | 2020 |
| Nordagutu Skogsbilveger SA | Real estate | 1956 |
| Nordbøåsen Tomteselskap AS | Real estate | 2014 |
| Nordre Nes AS | Wholesale & retail | 2018 |
| Norice Seafood AS | Wholesale & retail | 2004 |
| Norsjø Arkitekter AS | Professional & scientific | 2010 |
| Norsjø Eiendomskompetanse AS | Real estate | 2016 |
| Norsjø Sag & Høvleri A/S | Manufacturing | 1963 |
| Norsk Eplefest AS | Professional & scientific | 2009 |
| Norway's Motor Vehicles AS | Wholesale & retail | 2020 |
| Notevarp AS | Real estate | 2005 |
| Notevarp Eiendom AS | Real estate | 2003 |
| Orekåsa Eiendom AS | Real estate | 2004 |
| Orekåsa Holding AS | Real estate | 2011 |
| Parwar Eiendom & Bilauto Da | Real estate | 2010 |
| Per Øyvind Moen Holding AS | | 2019 |
| Proff Eiendomsutvikling AS | Real estate | 2008 |
| Respons Design AS | Information & communication | 2024 |
| Restaurantdiary AS | Information & communication | 2017 |
| Revisorteam Midt-Telemark AS | Professional & scientific | 2019 |
| Rundtomvegen SA | Real estate | 1985 |
| Ryntveit Maskin AS | Manufacturing | 2024 |
| Rørleggermestern AS | Construction | 2011 |
| S.I.Haugerud Consulting AS | Professional & scientific | 2009 |
| Sa-Ho AS | Professional & scientific | 2017 |
| SBT Eiendom 1 AS | Real estate | 2001 |
| Sisjord AS | Construction | 2023 |
| Skarsdalsvegen SA | Real estate | 1989 |
| Slemmelid Bilgummi AS | Wholesale & retail | 2022 |
| Snippen Holding AS | Professional & scientific | 2020 |
| Snøhula AS | Real estate | 2022 |
| Solheim E Holding AS | Real estate | 2014 |
| Solheim Lie AS | Real estate | 2014 |
| St-Elektroservice AS | Construction | 2012 |
| Steig Hytter AS | Real estate | 2025 |
| Storkaas Handel AS | Wholesale & retail | 2014 |
| Strannavegen 343 AS | Real estate | 2022 |
| Støen Service Og Utleie AS | Administrative & support | 2025 |
| Sunde Kjøl Og Frys AS | Construction | 2023 |
| Sæland Prosjekt AS | Professional & scientific | 2025 |
| T Hamre Eiendom AS | Real estate | 2016 |
| Teksten Camping AS | Hospitality | 1998 |
| Tele Tbe Utvikling AS | Real estate | 2022 |
| Telefrukt AS | Wholesale & retail | 1993 |
| Telefrukt Produsentlag SA | Wholesale & retail | 1980 |
| Telemark Antirust AS | Other services | 2022 |
| Telemark Blåseisolering AS | Construction | 2022 |
| Telemark Byggentreprenør AS | Construction | 2016 |
| Telemark Byggentreprenør Eiendom AS | Real estate | 2017 |
| Telemark Byggentreprenør Holding AS | Construction | 2019 |
| Telemark Byggentreprenør Utvikling AS | Real estate | 2017 |
| Telemark Frukthageservice AS | Agriculture & fishing | 2017 |
| Telemark Plommeutvikling Da | Agriculture & fishing | 2007 |
| Telemark Vaktselskap AS | Administrative & support | 2006 |
| Telemarksfrukt Da | Agriculture & fishing | 2005 |
| TFH Eiendom AS | Real estate | 2022 |
| The Fruit Group AS | Real estate | 2021 |
| Tjommen Petroleum AS | | 2026 |
| Torshølvegen 6 AS | Real estate | 2021 |
| Totaleiendom AS | Real estate | 2005 |
| Tre Og Portal AS | Construction | 1991 |
| TSK Consulting AS | Professional & scientific | 2022 |
| Veco AS | Agriculture & fishing | 2025 |
| W Bilpleie AS | Other services | 2026 |
| Werenskiold Invest AS | Professional & scientific | 2024 |
| Wollberg Service AS | Manufacturing | 2008 |