| Bishop Auckland Golf Club Trading Ltd | Hospitality | 2024 |
| Bishop Auckland Merchandise Limited | Wholesale & retail | 2023 |
| Bishop Auckland PUB Company Ltd | Hospitality | 2026 |
| Bishop Auckland Rugby Union Football Club Limited | Arts & recreation | 2019 |
| Bishop Auckland Tandoori Ltd | Hospitality | 2024 |
| Bishop Auckland Trading Limited | Hospitality | 2024 |
| Bishop Auckland Tyres 'N' Tests Limited | Other services | 2010 |
| Bishop Bertos Ltd | Hospitality | 2018 |
| Bishop Bertos Pizza Ltd | Hospitality | 2024 |
| Bishop Eats Ltd | Hospitality | 2026 |
| Bishop Middleham Plant & Recycling Limited | Administrative & support | 2012 |
| Bishop Trains Limited | Administrative & support | 2021 |
| Bishop United CIC | Arts & recreation | 2019 |
| Bishop’S Grill Ltd | Hospitality | 2024 |
| BJS Farms Ltd | Agriculture & fishing | 2010 |
| BKZ Driver Ltd | Transport & logistics | 2022 |
| BKZ Transport Ltd | Transport & logistics | 2022 |
| Black and Heale Construction Ltd | Manufacturing | 2022 |
| Black and Heale Timber Frames Ltd | Manufacturing | 2023 |
| Black Diamond Exotics Ltd | Wholesale & retail | 2026 |
| Black Diamond Property Group Ltd | Real estate | 2026 |
| Black Diamond Ventures Ltd | Wholesale & retail | 2026 |
| Black Thistle (Close Protection) Ltd. | Administrative & support | 2025 |
| Blackbear Consultancy Services Ltd | Information & communication | 2026 |
| Blackdene Consulting Limited | Professional & scientific | 2022 |
| Blacklock Jewellery Ltd | Wholesale & retail | 2025 |
| Blenkiron Holdings Ltd | Other services | 2024 |
| Blitz Floor Cleaning Ltd | Extraterritorial | 2025 |
| Block Stack Ltd | Information & communication | 2025 |
| BLR Restorations Limited | Construction | 2019 |
| Blucurve Limited | Wholesale & retail | 2009 |
| Blue Flame Plumbing and GAS Limited | Professional & scientific | 2013 |
| Blue Mile Care Ltd | Health & social care | 2024 |
| Blue Wing Marketing Limited | Information & communication | 2024 |
| BMB Ltd | Wholesale & retail | 2020 |
| Bobby Millican Equestrian Ltd | Arts & recreation | 2025 |
| Bobby's Sports Ltd | Arts & recreation | 2026 |
| Bodhi ZEN Clinic Limited | Other services | 2016 |
| Bondgate Fisheries Limited | Hospitality | 2003 |
| Bondgate Holdings Ltd | Real estate | 2017 |
| Bondgate Lettings Limited | Hospitality | 2021 |
| Bondisle Garage Limited | Wholesale & retail | 2011 |
| Boomex Limited | Extraterritorial | 2012 |
| Borderland (Kelso) Limited | Construction | 2021 |
| Boss Hydro Creations Limited | Manufacturing | 2019 |
| Bounder Copse Management Company (2010) Ltd | Households | 2011 |
| Bourdais Limited | Financial services | 2022 |
| Bowlees Holiday Lettings Ltd | Hospitality | 2019 |
| Bowman & SON Escorting Ltd | Transport & logistics | 2025 |
| Bowtastic Clips Ltd | Wholesale & retail | 2018 |
| Box Architectural Services Limited | Professional & scientific | 2020 |
| BPR Mart Ltd | Wholesale & retail | 2025 |
| Brad Wood Racing Limited | Arts & recreation | 2026 |
| Bradbury Commercials Ltd | Wholesale & retail | 2025 |
| Bradley Hall Land Management Limited | Real estate | 2014 |
| Bradley Mill Caravan Site Limited | Hospitality | 1971 |
| Bread and Salt Hospitality Ltd | Hospitality | 2024 |
| Breaking Bread Durham Limited | Hospitality | 2018 |
| Breaking Bread Durham Market Ltd | Wholesale & retail | 2020 |
| Breckon Timber Frame Ltd | Construction | 2026 |
| Brian Wragg Haulage Ltd | Transport & logistics | 2008 |
| Bricon International Limited | Real estate | 2017 |
| Bride & Groove Limited | Information & communication | 2021 |
| Bridge Creative Enterprise C.I.C. | Administrative & support | 2018 |
| Brigantia Capital Ltd | Financial services | 2023 |
| Brighter Bookkeeping Solutions Limited | Professional & scientific | 2019 |
| Broken Sky Media Ltd | Information & communication | 2017 |
| Brownson & Sons Limited | Construction | 2023 |
| Brucey Bakes Ltd | Wholesale & retail | 2026 |
| BSB Electrical Services(Ne) Ltd | Construction | 2025 |
| BT Building Services Limited | Construction | 2022 |
| BTL Timber and Hardware Limited | Manufacturing | 2008 |
| Buckingham Green Management Company Limited | Real estate | 2018 |
| Buddies Holdings Limited | Financial services | 2026 |
| Buddies Nursery Limited | Education | 2016 |
| Buddies Property Limited | Real estate | 2026 |
| Bugsy Foods Ltd | Hospitality | 2025 |
| Bugzy Malones Limited | Hospitality | 2025 |
| Burniston Management Company Limited | Households | 2023 |
| Burwood Heights Management Company Limited | Households | 2012 |
| Bush Interiors Ltd | Manufacturing | 2022 |
| Business Class UK Ltd | Extraterritorial | 2021 |
| Business of Words Ltd | Information & communication | 2024 |
| Byker PUB Company Limited | Hospitality | 2017 |
| C & a Agricultural Engineering Limited | Manufacturing | 2007 |
| C & C Aldred Limited | Construction | 2011 |
| C & C Forster Limited | Wholesale & retail | 2002 |
| C & T Construction Services Ltd | Construction | 2024 |
| C Harrison Electrical Services Ltd | Construction | 2025 |
| C J Roofing Services Limited | Construction | 2012 |
| C M W Utilities Limited | Energy | 2008 |
| C S Housing Rentals Ltd | Real estate | 2024 |
| C S Mills Joiners & Builders Ltd | Construction | 2017 |
| C&A Structural and Design Services Ltd | Construction | 2025 |
| C.A. (Evenwood) Limited | Real estate | 2000 |
| C.A. Group (Holdings) Limited | Construction | 2006 |
| C.E.M.G Consultancy Limited | Health & social care | 2023 |
| C.E.N.T Hospitality Ltd | Hospitality | 2025 |
| C.Potts Groundworks Limited | Construction | 2014 |
| C.S Building & Roofing Ltd | Construction | 2026 |