| Bjørnsonsgt 8 AS | Real estate | 1980 |
| Bjørnvei AS | Real estate | 2007 |
| Bkss Holding AS | | 2024 |
| Blaast AS | Information & communication | 2017 |
| Blichfeldt Aktiv AS | Professional & scientific | 2017 |
| Blikknils AS | Professional & scientific | 2025 |
| BLL Eiendom AS | Real estate | 2022 |
| Blond Gjøvik AS | Other services | 2018 |
| Blåflat Invest AS | Financial services | 2014 |
| BMG AS | Professional & scientific | 2013 |
| Bmvs AS | Information & communication | 2025 |
| BMZ Eiendom AS | Real estate | 2015 |
| Boa Invest AS | Real estate | 2005 |
| Boardshop 2816 AS | Wholesale & retail | 2021 |
| Boligdrøm AS | Construction | 2024 |
| Boligskredderiet AS | Wholesale & retail | 2025 |
| Bonamat Norge AS | Wholesale & retail | 1989 |
| Bondelia Utvikling AS | Real estate | 2015 |
| Bondlid Utvikling AS | Financial services | 2018 |
| Bookify AS | Information & communication | 2018 |
| Boost Holding AS | Real estate | 2018 |
| Boqueria De Grace AS | Hospitality | 2025 |
| Bosanova AS | Financial services | 2012 |
| Bowling 1 Franchise AS | Administrative & support | 1999 |
| Bowling 1 Gjøvik AS | Arts & recreation | 1998 |
| Bowlingbygget AS | Real estate | 2021 |
| Boxstyle AS | Construction | 2023 |
| BP Brannkompetanse AS | Education | 2005 |
| BP Utvikling AS | Real estate | 2021 |
| BPN Da | Real estate | 2005 |
| Bra Renhold Og Miljøservice AS | Administrative & support | 2022 |
| Braastad Patrick Og Eva Ans | Hospitality | 1995 |
| Braathen Holding AS | Real estate | 2005 |
| Bragd Kompetanse AS | Health & social care | 2014 |
| Bragd Utvikling AS | Education | 2019 |
| Bralk Eiendom AS | Real estate | 2014 |
| Bralk Mjøsstranda AS | Real estate | 2012 |
| Brand Altitude AS | Professional & scientific | 2024 |
| Brasse AS | Real estate | 2007 |
| Bratberg Og Stubberud AS | Construction | 1983 |
| Brennerivegen 1 Og 3 AS | Real estate | 2006 |
| Brennhaug Handel AS | Wholesale & retail | 2023 |
| Brigade AS | Administrative & support | 2023 |
| Brillenova AS | Wholesale & retail | 2025 |
| Briskeby Eiendom 1 AS | Real estate | 2006 |
| Brokerud Holding AS | | 2018 |
| Brotec Da | Wholesale & retail | 2010 |
| Brugata 17 Brumunddal AS | Real estate | 2023 |
| Brusvefaret Grendelag SA | Real estate | 1983 |
| Brygga Gjøvik AS | Hospitality | 2022 |
| Bryggeveien 7-9 AS | Real estate | 2008 |
| Bråstadlia Handelslag AS | Real estate | 2019 |
| Bråstadvika Fritidsboliger AS | Real estate | 2011 |
| Brændhaugen Holding AS | Financial services | 2005 |
| Brødrene Lysgård Tak & Fasade Ans | Construction | 2006 |
| BSB Design AS | Wholesale & retail | 2026 |
| Buan Invest AS | Financial services | 2015 |
| Bue AS | Financial services | 2005 |
| Bugg AS | | 2021 |
| Busk AS | Real estate | 2022 |
| Butikkdrift Andersen AS | Wholesale & retail | 2025 |
| Butikkdrift Daniel Alejandro Contreras AS | Wholesale & retail | 2026 |
| Bygg & Trevare AS | Real estate | 2017 |
| Bygg & Trevare Eiendom AS | Real estate | 2017 |
| Bygg & Trevare Holding AS | Real estate | 2020 |
| Bygg-Male Service AS | Construction | 2018 |
| Byggedrøm AS | Professional & scientific | 2024 |
| Byggingeniør Kåseth AS | Professional & scientific | 2020 |
| BYGGKONSULT1 AS | Professional & scientific | 2013 |
| Byggmester Anders Skogen AS | Construction | 2019 |
| Byggmester Magne Fjellhaug AS | Construction | 1999 |
| Byggmester Schnell AS | Construction | 2007 |
| Byggs AS | Construction | 2023 |
| Byggverk AS | Construction | 2019 |
| Bysmak AS | Hospitality | 2025 |
| Bzaw AS | Other services | 2022 |
| Bøgata 55 AS | Real estate | 2014 |
| C a Holding AS | | 2024 |
| C.B Eiendom AS | Real estate | 2026 |
| C.Johnsen Holding AS | Information & communication | 2022 |
| Caliber Invest AS | Real estate | 2012 |
| Carinn AS | Wholesale & retail | 2024 |
| Casamanjana AS | Hospitality | 2006 |
| Casensia AS | Wholesale & retail | 2023 |
| Cbu Bolig AS | Real estate | 2011 |
| CC Eiendom Drift AS | Administrative & support | 2000 |
| CC Gasolin Gjøvik AS | Real estate | 2010 |
| CC Gjøvik Eiendom AS | Real estate | 1984 |
| CC Helse AS | Health & social care | 2019 |
| Cellulosevegen 4 AS | Real estate | 2007 |
| Cephika Norsk Strikkedesign AS | Professional & scientific | 2020 |
| Certchain AS | Professional & scientific | 2023 |
| CG Nord Media AS | Information & communication | 2021 |
| Chamonix AS | Real estate | 2002 |
| Chrismess AS | Wholesale & retail | 2018 |
| Christiania Boligutleie AS | Real estate | 2012 |
| City Home Tjuvholmen AS | Real estate | 2017 |
| CJ Veterinærtjenester AS | Professional & scientific | 2023 |
| CK Gulbrandsen Invest AS | | 2022 |
| Clean Metal Processes AS | Professional & scientific | 2012 |