| Bloochip Ltd | Manufacturing | 2012 |
| Bloochip Tool Room Services Ltd | Manufacturing | 2024 |
| Blossom Cocktail Bar Ltd | Hospitality | 2024 |
| BLU Room Architecture Ltd | Professional & scientific | 2016 |
| Blubern Ltd | Wholesale & retail | 2024 |
| Blue Elsa Ltd | Health & social care | 2020 |
| Blue Events 2024 Ltd | Wholesale & retail | 2024 |
| Blue FOX Caravans Ltd | Wholesale & retail | 2023 |
| Blue Gaydon Ltd | Professional & scientific | 2024 |
| Blue Ghost Group Ltd | Transport & logistics | 2020 |
| Blue House Darlington Ltd | Hospitality | 2020 |
| Blue's Bottles Ltd | Wholesale & retail | 2019 |
| Bluebox Business Space Ltd | Administrative & support | 2019 |
| BM Print Shop Ltd | Extraterritorial | 2019 |
| BMD Civils Ltd | Construction | 2019 |
| BMS Overseas Limited | Manufacturing | 2002 |
| BN Trans Ltd | Transport & logistics | 2019 |
| BNM Energy Ltd | Professional & scientific | 2017 |
| Boardroom Ventures Ltd | Professional & scientific | 2026 |
| Body Doctors NE Ltd | Arts & recreation | 2025 |
| Bodyshop Logistics Ltd | Transport & logistics | 2019 |
| Bohemian Property Holdings Ltd | Real estate | 2019 |
| Boiler FIX NE Ltd | Construction | 2019 |
| Bold Bloc Design Limited | Wholesale & retail | 2009 |
| Bolted Ltd | Manufacturing | 2026 |
| Bolton SDL Ltd | Other services | 2022 |
| Bonafide Peptides Ltd | Wholesale & retail | 2026 |
| Bondgate Foods Ltd | Hospitality | 2024 |
| Bondgate I.T. Services Limited | Information & communication | 1998 |
| Bondgate Innovation Group Limited | Financial services | 2020 |
| Bondgate Retail Ltd | Extraterritorial | 2010 |
| Bondgate UK Limited | Professional & scientific | 2007 |
| Bonnie Property (NE) Ltd | Real estate | 2024 |
| Book Hobby Limited | Wholesale & retail | 2025 |
| Borama Engineering Ltd | Manufacturing | 2014 |
| Borealis Consulting Ltd | Professional & scientific | 2010 |
| Born Decom Services Limited | Professional & scientific | 2025 |
| Born to Suceed Limited | Professional & scientific | 2021 |
| Borngreat Motors Ltd | Wholesale & retail | 2026 |
| Borrows Consulting Limited | Professional & scientific | 2021 |
| Borthwick Construction Limited | Construction | 2019 |
| Bounce Equestrian Ltd | Agriculture & fishing | 2018 |
| Bourne Court Residents' Association Limited | Other services | 2000 |
| Bowes Properties Ltd | Real estate | 2024 |
| Bowness Properties Ltd | Construction | 1977 |
| Bowtell Roofing and Cladding Solutions Ltd | Construction | 2025 |
| Bowtie Safety & Risk Limited | Professional & scientific | 2024 |
| Box-Well Ltd | Education | 2019 |
| Boxfit Ltd | Arts & recreation | 2009 |
| Boxfusion Consulting Limited | Information & communication | 2010 |
| Boyah Limited | Wholesale & retail | 2026 |
| BP Carpentry Limited | Construction | 2013 |
| BPH Commercial Limited | Wholesale & retail | 2022 |
| BRA Lady Darlington Ltd | Wholesale & retail | 2016 |
| Brad Davies Haulage Ltd | Transport & logistics | 2026 |
| Braddan (Saars) Ltd | Professional & scientific | 2010 |
| Braddan Group Ltd | Financial services | 2010 |
| Braddan Plant Hire Ltd | Administrative & support | 2014 |
| Braddan Structures Limited | Construction | 2008 |
| Bradley's Antique Packing Services Limited | Administrative & support | 2014 |
| Bradley's Furniture Carriers Limited | Transport & logistics | 2004 |
| Braithwaite Engineering Ltd | Wholesale & retail | 2020 |
| Braithwaites Haulage Limited | Transport & logistics | 2016 |
| Bramble Business Insights LLP | | 2018 |
| Bramley Consultation Services Ltd | Information & communication | 2020 |
| Brand Style Ltd | Hospitality | 2018 |
| Branded CUP Group Ltd | Manufacturing | 2026 |
| Brandon Limited | Information & communication | 2019 |
| Brasa Prime Ltd | Wholesale & retail | 2026 |
| Brass Holdings Ltd | Construction | 2023 |
| Brave Hearts North East CIC | Health & social care | 2020 |
| Brazlogistic Ltd | Wholesale & retail | 2025 |
| Break Arena Limited | Education | 2025 |
| Brett Cockburn Logistics Ltd | Transport & logistics | 2025 |
| Bricklane Hairdressing Limited | Other services | 2018 |
| Bricklayers Tools Limited | Wholesale & retail | 2022 |
| Bridge Court Residents Association Limited | Households | 1988 |
| Brierdale Landscapes Ltd | Administrative & support | 2019 |
| Brigantia Productions Limited | Information & communication | 2020 |
| Brigantium Designs Limited | Manufacturing | 2015 |
| Bright Cubez ( UK) Ltd | Wholesale & retail | 2025 |
| Bright Frog Ltd | Information & communication | 2014 |
| Brightstar AI Solutions Limited | Information & communication | 2025 |
| Britcroft Logistics Ltd | Transport & logistics | 2021 |
| BRN Express Delivery Limited | Transport & logistics | 2021 |
| Broadway Daycare Limited | Education | 2011 |
| Brodie Holdings Darlington Limited | Hospitality | 2025 |
| Broken Homes Ltd | Construction | 2025 |
| Brollyboy Ltd | Information & communication | 2022 |
| Brook Cherith Health Care Services Limited | Health & social care | 2022 |
| Brookes HV Solutions Limited | Construction | 2026 |
| Brookson (5096J) Limited | Administrative & support | 2007 |
| Brookson (5267I) Limited | Professional & scientific | 2007 |
| Brotherhood Ventures Limited | Hospitality | 2014 |
| Brotherhoood Ventures Limited | Hospitality | 2025 |
| Brothers Y Medical Ltd | Health & social care | 2025 |
| Brownes Artisan Butchers Limited | Wholesale & retail | 2019 |
| Brownless Cleaning Specialists Ltd | Administrative & support | 2018 |
| Brownlow Cars Ltd | Wholesale & retail | 2022 |
| Browns Fabrications Limited | Manufacturing | 2002 |