| Trolla Invest AS | Financial services | 2005 |
| Trolla Næringspark AS | Real estate | 1994 |
| Trollahaugen 35 AS | Real estate | 2023 |
| Trollheim - Spill AS | Wholesale & retail | 2026 |
| Trollhetta Eiendom AS | Real estate | 2020 |
| Trollmann AS | | 2026 |
| Trollsjø Holding AS | Information & communication | 2023 |
| Tromek Produksjon AS | Manufacturing | 2016 |
| Tromek Service AS | Manufacturing | 2016 |
| Tron Auto AS | Other services | 2019 |
| Trond Industries AS | Information & communication | 2025 |
| Trondheim 2030 AS | Administrative & support | 2025 |
| Trondheim Action AS | Administrative & support | 2013 |
| Trondheim Antirustsenter AS | Other services | 2012 |
| Trondheim Areal AS | Real estate | 2019 |
| Trondheim Betong AS | Construction | 2006 |
| Trondheim Biffhus AS | Hospitality | 2022 |
| Trondheim Bil AS | Wholesale & retail | 2019 |
| Trondheim Bilformidling AS | Wholesale & retail | 2015 |
| Trondheim Bilkollektiv SA | Other services | 1996 |
| Trondheim Biltest AS | Professional & scientific | 2013 |
| Trondheim Blomster AS | Wholesale & retail | 2005 |
| Trondheim Boatman AS | Transport & logistics | 2013 |
| Trondheim Body Vip Clinique Da | Arts & recreation | 1989 |
| Trondheim Boligdesign AS | Professional & scientific | 2024 |
| Trondheim Boligutleie AS | Real estate | 2018 |
| Trondheim Boligutvikling AS | Real estate | 2010 |
| Trondheim Brudekjoler Ans | Wholesale & retail | 2024 |
| Trondheim by Boat AS | Administrative & support | 2019 |
| Trondheim Bygg AS | Construction | 2026 |
| Trondheim Bygg-Service AS | Construction | 2007 |
| Trondheim Byggteknikk AS | Construction | 2021 |
| Trondheim Catering AS | Hospitality | 2017 |
| Trondheim Concerts AS | Arts & recreation | 2012 |
| Trondheim Consulting AS | Professional & scientific | 2016 |
| Trondheim Crew AS | Arts & recreation | 2016 |
| Trondheim Cruise Network Mid-Norway SA | Professional & scientific | 2009 |
| Trondheim Dronetjenester AS | Professional & scientific | 2022 |
| Trondheim Eiendom AS | Real estate | 2016 |
| Trondheim Eiendomsforvaltning AS | Real estate | 2025 |
| Trondheim Eiendomsinvest 2 AS | Real estate | 2019 |
| Trondheim Eiendomsmegling AS | Real estate | 2010 |
| Trondheim Eiendomsselskap 1 AS | Real estate | 2020 |
| Trondheim Eiendomsselskap AS | Real estate | 2020 |
| Trondheim Eiendomsservice AS | Construction | 2015 |
| Trondheim Eiendomsutvikling AS | Real estate | 2011 |
| Trondheim Elektroservice AS | Construction | 2008 |
| Trondheim Elsykkel AS | Wholesale & retail | 2007 |
| Trondheim Estate AS | Manufacturing | 1998 |
| Trondheim Flylegesenter AS | Health & social care | 2023 |
| Trondheim for You - Guided Tours AS | Administrative & support | 2019 |
| Trondheim Forsikring AS | Financial services | 2020 |
| Trondheim Forsikringssenter AS | Financial services | 2000 |
| Trondheim Fotklinikk AS | Health & social care | 2023 |
| Trondheim Frakt AS | Transport & logistics | 2019 |
| Trondheim Fysikalske Institutt AS | Health & social care | 2014 |
| Trondheim Glass-Service AS | Construction | 1988 |
| Trondheim Golfsenter AS | Arts & recreation | 2002 |
| Trondheim Guide Service & Sykkelguide AS | Administrative & support | 2011 |
| Trondheim Gym AS | Arts & recreation | 2017 |
| Trondheim Helse - Og Utviklingssenter Da | Health & social care | 2010 |
| Trondheim Historiske Bygninger AS | Real estate | 2025 |
| Trondheim Hjertesenter AS | Health & social care | 1996 |
| Trondheim Hockeyshop AS | Wholesale & retail | 2014 |
| Trondheim Hudlegesenter AS | Health & social care | 2000 |
| Trondheim Hørsel Klinikk AS | Health & social care | 2018 |
| Trondheim Idrettsklinikk AS | Health & social care | 2013 |
| Trondheim Idrettsungdomsskole AS | Education | 2014 |
| Trondheim Innovation AS | Professional & scientific | 2016 |
| Trondheim Kampsportsenter AS | Real estate | 2002 |
| Trondheim Kickboxing AS | Arts & recreation | 2018 |
| Trondheim Kino AS | Information & communication | 1999 |
| Trondheim Kino Eiendom AS | Real estate | 2012 |
| Trondheim Kino Utvikling AS | Information & communication | 2011 |
| Trondheim Kjøle- Og Fryselager AS | Transport & logistics | 1995 |
| Trondheim Kontoreiendom AS | Real estate | 2018 |
| Trondheim Kooperativ SA | Wholesale & retail | 2016 |
| Trondheim Kultur & Næring AS | Arts & recreation | 2007 |
| Trondheim Kunstformidling Ans | | 1985 |
| Trondheim Laserlounge AS | Other services | 2024 |
| Trondheim Leilighetshotell AS | Hospitality | 2011 |
| Trondheim Liftutleie AS | Administrative & support | 2014 |
| Trondheim Limousine AS | Transport & logistics | 2017 |
| Trondheim Lungelegesenter AS | Health & social care | 2008 |
| Trondheim Lyd AS | Arts & recreation | 2004 |
| Trondheim Lyd Holding AS | Arts & recreation | 2024 |
| Trondheim Lys AS | Wholesale & retail | 2018 |
| Trondheim Mage- Og Tarmsenter AS | Health & social care | 2021 |
| Trondheim Malerservice AS | Construction | 2009 |
| Trondheim Management AS | Real estate | 2010 |
| Trondheim Manuell Terapi AS | Health & social care | 2005 |
| Trondheim Maritime Senter AS | Real estate | 2007 |
| Trondheim Marketing Ans | Professional & scientific | 1992 |
| Trondheim Maskinutleie AS | Administrative & support | 2015 |
| Trondheim Messeselskap AS | Administrative & support | 1997 |
| Trondheim Murservice AS | Construction | 2004 |
| Trondheim Musikalske Institutt Da | Education | 2006 |
| Trondheim Musikkpark Da | Education | 2010 |
| Trondheim Næringspark AS | Real estate | 2008 |
| Trondheim Padel AS | Real estate | 2019 |