| Brannspesialisten AS | Wholesale & retail | 1999 |
| Bransjetjenester Notodden AS | Professional & scientific | 2022 |
| Bratteng Invest AS | Financial services | 2018 |
| Brattrein Eiendom AS | Real estate | 2013 |
| Brattrein Hotell AS | Hospitality | 2002 |
| Broma AS | Construction | 2022 |
| Bråtelia Eiendom AS | Real estate | 2022 |
| Bråtelia Holding AS | Wholesale & retail | 2022 |
| Buried Beneath Interactive AS | Information & communication | 2024 |
| Butikk 473 Kvantum Varehus Helge Og June's Kiosk Da | Wholesale & retail | 2004 |
| Byenglene Helse & Omsorg Da | Health & social care | 2002 |
| Bygg Telemark AS | Construction | 2024 |
| Bygg-Tech AS | Professional & scientific | 2015 |
| Byggmester Anders Bakken AS | Construction | 2018 |
| Byggmester Jonny Solbjørg AS | Construction | 2006 |
| Byggmester Sletta AS | Construction | 2026 |
| Byggverket Ans | Construction | 2003 |
| Byggverket AS | Construction | 2020 |
| Byløndal AS | Information & communication | 2024 |
| C8 Holding AS | Professional & scientific | 2017 |
| Canelana AS | Wholesale & retail | 2007 |
| Carolina Invest AS | Real estate | 2017 |
| Catering Kompaniet AS | Professional & scientific | 2012 |
| Cave-Holding AS | | 2022 |
| Centrum Bilpleie Notodden AS | Other services | 2018 |
| Centrum Bilverksted AS | Other services | 2006 |
| Chateau De Tuddal AS | Real estate | 2020 |
| Chef Service AS | Hospitality | 2022 |
| CK Akademiet AS | Education | 2024 |
| Cloumann Meyer Invest AS | | 2025 |
| Cmoneo AS | Information & communication | 2012 |
| Cowardgården AS | Real estate | 2016 |
| CR Maskin Og Utemiljø AS | Construction | 2024 |
| Curlsport Distribution AS | Wholesale & retail | 2021 |
| Dag Morgan Bakken AS | | 2019 |
| Dali Invest AS | | 2016 |
| Dalian Holding AS | | 2024 |
| Danys Cafe AS | Hospitality | 2017 |
| Dimi Holding AS | Real estate | 2021 |
| Diskre Transport Ltd Nuf | Transport & logistics | 2026 |
| Djerv Medic AS | Health & social care | 2021 |
| DJK Holding AS | | 2026 |
| Dorholt Maskin AS | Construction | 2022 |
| Drage Industries AS | Real estate | 2007 |
| Draupne Consult AS | Professional & scientific | 2016 |
| Drivarselskapet Breisetvegen | Real estate | 1995 |
| DRM Eiendom AS | Real estate | 2026 |
| Dscplnd AS | Wholesale & retail | 2024 |
| DSS STORGT.40 AS | Real estate | 2005 |
| DT Anleggstjenester AS | Construction | 2015 |
| Dugg Sauna AS | Administrative & support | 2021 |
| Duken Lavpris AS | Wholesale & retail | 1999 |
| Dyrlegen På Notodden AS | Professional & scientific | 2020 |
| E- Tek AS | Professional & scientific | 2021 |
| Eaa Holding AS | Construction | 2013 |
| Edge Group AS | Real estate | 2014 |
| Edge Invest AS | Real estate | 2020 |
| Edgeperformance AS | Wholesale & retail | 2021 |
| Eek Eiendom AS | Real estate | 2008 |
| Eek Holding AS | Real estate | 2008 |
| Eek Logistikk AS | Transport & logistics | 2016 |
| Eek Murstad Eiendom AS | Real estate | 2023 |
| Ehoff AS | Wholesale & retail | 2021 |
| Eik Corp AS | | 2026 |
| Elastisk AS | Information & communication | 2015 |
| Electronic Norge Da | Wholesale & retail | 2005 |
| Elektriker'N Sauherad AS | Construction | 2008 |
| Elgsjø Kafe AS | Hospitality | 2020 |
| Elines Gaver AS | Wholesale & retail | 2007 |
| Elverhøi Holding AS | | 2023 |
| Em Bygg Ans | | 1988 |
| Endless Rain Da | Manufacturing | 2000 |
| Energeia Notodden AS | Energy | 2024 |
| Enfy AS | Professional & scientific | 2023 |
| Enfy Holding AS | | 2023 |
| Engravslia Og Syftestad Maskin AS | Construction | 2018 |
| Environtec Aqua AS | Manufacturing | 2017 |
| Erik Dahl Invest AS | Real estate | 2000 |
| Erlend Bakken AS | Real estate | 2020 |
| Evac Norway AS | Professional & scientific | 1993 |
| Everket AS | Energy | 1993 |
| Evolve Trafikksenter Notodden AS | Education | 2021 |
| Ew Holding AS | Financial services | 2005 |
| Extruding Eiendom AS | Real estate | 1963 |
| Eyde Bar & Restaurant AS | Hospitality | 2015 |
| Ezbench Solutions AS | Information & communication | 2022 |
| Eztheory AS | Professional & scientific | 2021 |
| F-Larsen Holding AS | | 2023 |
| Farmacan AS | Wholesale & retail | 2020 |
| Fast on Eva AS | Hospitality | 2023 |
| Felicias Have AS | Hospitality | 2020 |
| Felle Eiendomsutvikling AS | Real estate | 2019 |
| Felle Eiendomsutvikling Tomt 1 AS | Real estate | 2023 |
| Felle Eiendomsutvikling Tomt 2 AS | Real estate | 2023 |
| Felle Eiendomsutvikling Tomt 3 AS | Real estate | 2023 |
| Felle Eiendomsutvikling Tomt 5 AS | Real estate | 2023 |
| Felle Eiendomsutvikling Tomt 8 AS | Real estate | 2025 |
| Fem Invest AS | Real estate | 2012 |
| Femmer'N AS | Hospitality | 2012 |
| Fi Holding AS | | 2025 |