| Barronvale Ltd | Wholesale & retail | 2025 |
| Barry Summers & Co Limited | Professional & scientific | 2016 |
| Basolite Ltd | Manufacturing | 2021 |
| Batu Serin Ltd | Wholesale & retail | 2026 |
| Baydigital Ltd | Wholesale & retail | 2024 |
| Beanova Ltd | Wholesale & retail | 2026 |
| Bearbert Ltd | Hospitality | 2024 |
| Bearlaven Ltd | Hospitality | 2025 |
| Becks Digital Ltd | Professional & scientific | 2018 |
| BEE Smooth Ltd | Health & social care | 2021 |
| Beeches Technical Services Ltd | Professional & scientific | 2011 |
| Bentham DJ Ltd | Hospitality | 2018 |
| Bentham SL Ltd | Wholesale & retail | 2011 |
| Betty Kisses Academy Limited | Other services | 2021 |
| Betty Kisses Limited | Other services | 2019 |
| BGS Ilyas Ltd | Wholesale & retail | 2025 |
| Bigcloud Trade Ltd | Wholesale & retail | 2025 |
| Bj's Taxis Limited | Transport & logistics | 2019 |
| Black&Mai Ltd | Wholesale & retail | 2025 |
| Blackbird Interiors Co (N.E.) Ltd | Professional & scientific | 2026 |
| Blackwater Solutions Ltd | Information & communication | 2018 |
| Blank Media Supplies Limited | Administrative & support | 2016 |
| BLINDS4YOU Limited | Wholesale & retail | 2020 |
| Bling Your Swing Limited | Other services | 2020 |
| Bloom N Witches Ltd | Hospitality | 2022 |
| BND Trading Limited | Wholesale & retail | 2024 |
| Body London United Ltd | Wholesale & retail | 2024 |
| Bondgate Electrical Distribution Limited | Wholesale & retail | 1993 |
| Bonessa Shop Global Ltd | Wholesale & retail | 2026 |
| Bosphera Co Ltd | Wholesale & retail | 2025 |
| Bosten Consultants Limited | Professional & scientific | 2012 |
| Box 43 Ltd | Hospitality | 2017 |
| Boyd Bidco Limited | Education | 2020 |
| Boyd Midco 2 Limited | Education | 2020 |
| Boyd Midco Limited | Education | 2020 |
| Boyd Topco Limited | Education | 2020 |
| Brancepeth Estates Ltd | Real estate | 2015 |
| Brancepeth Manor Park Ltd | Real estate | 2016 |
| Bravewell Limited | | 1989 |
| Brent Ardle Rope Access Ltd | Professional & scientific | 2020 |
| Brett Hyde Ltd | Other services | 2022 |
| Bridge Phonographics Limited | Arts & recreation | 1987 |
| Britannia Market Store Ltd | Wholesale & retail | 2026 |
| Britzen Trade Ltd | Wholesale & retail | 2026 |
| Burini Properties Limited | Real estate | 2023 |
| Bythepool.Co.Uk Limited | Administrative & support | 2021 |
| C & S Salon Essentials Limited | Wholesale & retail | 2014 |
| C Bamforth Roofing & Cladding Ltd | Construction | 2018 |
| C H M Rolling Stock Specialists Limited | Wholesale & retail | 2019 |
| C Stevenson Property Limited | Real estate | 2025 |
| C&K Diagnostics Ltd | Health & social care | 2021 |
| C. C. Jensen Limited | Manufacturing | 1990 |
| C. J. EMM Ltd | Professional & scientific | 2018 |
| CAA Commercial Management Ltd | Construction | 2025 |
| Cable and Taping (UK) Ltd | Manufacturing | 2021 |
| Cable North East Limited | Construction | 2012 |
| Caernis Limited | Information & communication | 2025 |
| Cafe Venture Limited | Hospitality | 2013 |
| Cahhh Services Limited | Administrative & support | 2013 |
| Campion Roofing & Cladding Limited | Construction | 2019 |
| Capella Commerce Ltd | Wholesale & retail | 2025 |
| Capture Films | Information & communication | 2004 |
| Car Connector Limited | Information & communication | 2025 |
| Car Tyre World Limited | Wholesale & retail | 2015 |
| Cares Group Holdings Limited | Health & social care | 1993 |
| Carl Greenwell Limited | Professional & scientific | 2011 |
| Carol Lesley Prockter Ltd | Extraterritorial | 2024 |
| Catchweight Comms Ltd | Professional & scientific | 2020 |
| Cathedral Taxis Limited | Transport & logistics | 2025 |
| Catterick MVR Ltd | Hospitality | 2025 |
| Cave Innovations Limited | Extraterritorial | 2011 |
| CCL Access and Coatings Limited | Construction | 2020 |
| Celikler Ltd | Wholesale & retail | 2026 |
| Charming Plume Global Ltd | Wholesale & retail | 2024 |
| Chris J Clark Transport Limited | Transport & logistics | 2018 |
| Chris Mcdonnell Golf Ltd | Education | 2025 |
| Chris Oliver Builder Ltd | Construction | 2019 |
| Chris Rimington Painting Ltd | Construction | 2022 |
| Cinam Property Investment Ltd | Real estate | 2020 |
| Citirix Ltd | Wholesale & retail | 2026 |
| Citizens Advice County Durham | Other services | 2013 |
| Civory Limited | Wholesale & retail | 2025 |
| CJG Management Limited | Administrative & support | 2026 |
| CKT Training Limited | Education | 2023 |
| CLA 3D Limited | Professional & scientific | 2024 |
| CLA Bespoke Flooring Solutions Ltd | Construction | 2024 |
| Classic Pizza (Spennymoor) Limited | Hospitality | 2005 |
| Clems Spennymoor Limited | Hospitality | 2017 |
| Clouded House Ltd | Wholesale & retail | 2016 |
| Club Community Partnership Limited | Other services | 2021 |
| CMG Dermatology Ltd | Health & social care | 2026 |
| Cobain IT Solutions Ltd | Information & communication | 2020 |
| Coban Store Ltd | Wholesale & retail | 2026 |
| Colin Smails Ltd | Wholesale & retail | 2002 |
| Colville Associates Limited | Professional & scientific | 2013 |
| Comiflex Limited | Professional & scientific | 2022 |
| CONNECT2(UK) Ltd | Wholesale & retail | 2015 |
| Cooper’S Crèche Limited | Other services | 2021 |
| Coralife Ltd | Wholesale & retail | 2025 |
| Corex E-Commerce Ltd | Wholesale & retail | 2025 |