| Blue Sea Pictures Limited | Information & communication | 2024 |
| Blue Sky Property (North East) Limited | Real estate | 2019 |
| Blue Square Trading Limited | Administrative & support | 1993 |
| Blue Wave Taekwondo Ltd | Education | 2022 |
| Blue Zone Residential Limited | Households | 2025 |
| Bluesky Accountancy Limited | Professional & scientific | 2013 |
| Bluesky Managed Payroll Services Limited | Extraterritorial | 2015 |
| Bluestream Management PMC Limited | Other services | 2020 |
| BMG NE Limited | Wholesale & retail | 2023 |
| Bmodern Interiors Ltd | Wholesale & retail | 2023 |
| BMV Recovery Limited | Transport & logistics | 2020 |
| Boar's Head Sunderland Ltd | Hospitality | 2026 |
| Boardwalk Leisure Limited | Hospitality | 2017 |
| BOB Gnarly Surf Ltd | Wholesale & retail | 2012 |
| Boba Cat Limited | Hospitality | 2020 |
| Bobina Ltd | Other services | 2022 |
| Bobo 1325 Limited | Arts & recreation | 2015 |
| BOC Care and Support Ltd | Health & social care | 2022 |
| BOC E-Learning Limited | Administrative & support | 2022 |
| BOC Virtual Agency Limited | Administrative & support | 2023 |
| Boho Hair Studio Ltd | Other services | 2023 |
| Bohol Consultancy Services Limited | Information & communication | 2015 |
| Boilex Ltd | Construction | 2024 |
| Bold Fashion Limited | Wholesale & retail | 2025 |
| Boldon Fish Bar Limited | Hospitality | 2024 |
| Boldon Vape Ltd | Wholesale & retail | 2025 |
| Boldstep Consulting Limited | Administrative & support | 2025 |
| Bollardscan Limited | Professional & scientific | 2016 |
| Bolt Distribution UK Ltd | Wholesale & retail | 2026 |
| Bonallie PUB Co Limited | Hospitality | 2025 |
| Bonners Raff RTM Company Limited | Real estate | 2021 |
| Bonnie SW Properties Ltd | Real estate | 2019 |
| Bonny LAD Productions Limited | Information & communication | 2025 |
| Bonsai Homes Ltd | Real estate | 2020 |
| BOO Developments Limited | Construction | 2024 |
| Book ME Serviced Accommodation Ltd | Administrative & support | 2025 |
| Bordeaux Rentals Ltd | Real estate | 2026 |
| Border Leathercrafts Limited | Wholesale & retail | 2006 |
| Borgrollswarner (UK) Limited | Extraterritorial | 2012 |
| Borna Ltd | Wholesale & retail | 2025 |
| Borngood CIC | Information & communication | 2025 |
| Boshers (NE) Ltd | Professional & scientific | 2015 |
| Boshotbari Ltd | Real estate | 2022 |
| Boss Cuts 1 Ltd | Other services | 2025 |
| Botanic Brand Ltd | Wholesale & retail | 2024 |
| Bould Brother Venture 2 Limited | Hospitality | 2025 |
| Bounce North East Ltd | Arts & recreation | 2016 |
| Boutique GX Ltd | Wholesale & retail | 2019 |
| Bowe Turner Ltd | Manufacturing | 2024 |
| Bowers & Mackinnon Optical Limited | Health & social care | 2006 |
| Bowes Court Management Company Limited | Professional & scientific | 2011 |
| Boxtrader Ltd | Wholesale & retail | 2024 |
| Boyce Assets Limited | Real estate | 2022 |
| Boyce Cars Limited | Wholesale & retail | 2025 |
| Boyd Industries Limited | Construction | 2018 |
| BP & SA Limited | Health & social care | 2024 |
| BPB Leisure Ltd | Hospitality | 2026 |
| BPP Visual Limited | Administrative & support | 2014 |
| Bppst Ltd | Hospitality | 2025 |
| Brace-Yourself Premium Sports & Orthopaedic Bracing Limited | Health & social care | 2021 |
| Bradlee Bute Logistics Ltd | Transport & logistics | 2025 |
| Braena Community Interest Company | Arts & recreation | 2010 |
| Braines Commercial Property Ltd | Real estate | 2025 |
| Braines Group Holdings Limited | Financial services | 2024 |
| Brandaxis Limited | Information & communication | 2026 |
| Brandling Park Mews Ltd | Real estate | 2025 |
| Brandling ST Properties Ltd | Real estate | 2025 |
| Brawny Ltd | Wholesale & retail | 2023 |
| BRD Utilities Ltd | Construction | 2023 |
| Breakfree Counselling Services Ltd | Health & social care | 2018 |
| Breakfree Training Ltd | Education | 2023 |
| Breakthrough Professional Services Limited | Professional & scientific | 2025 |
| Breese Wealth Management Limited | Professional & scientific | 2023 |
| Brewlab Limited | Professional & scientific | 1996 |
| Brewlab Technical Services Limited | Manufacturing | 2016 |
| Brian Clark Joinery Limited | Construction | 2010 |
| Brian Mackenow & Co Limited | Professional & scientific | 2011 |
| Brick & Bell Properties Ltd | Construction | 2026 |
| Bridge Food House Ltd | Hospitality | 2025 |
| Brierfield 1962 Limited | Extraterritorial | 2013 |
| Bright Impact CIC | Professional & scientific | 2024 |
| Bright Sparks Electrician & Property Maintenance Ltd | Households | 2026 |
| Brighter Academy Trust | Education | 2013 |
| Brighter Pathways North East CIC | Administrative & support | 2025 |
| Brightsparks Training Community Interest Company | Education | 2013 |
| Brillo Properties Ltd | Real estate | 2014 |
| Brini Solution Limited | Real estate | 2022 |
| Britcraft Studio Limited | Wholesale & retail | 2025 |
| British Esports | Arts & recreation | 2016 |
| British Esports Federation Limited | Arts & recreation | 2016 |
| Broadcasting Initiative Northern Development C.I.C. | Information & communication | 2025 |
| Brook Brothers Plumbing and Heating Ltd | Construction | 2025 |
| Brookdon Ltd | Information & communication | 2026 |
| Brookfield Gardens Management Company Limited | Administrative & support | 2007 |
| Brookside House (Sunderland) Management Limited | Administrative & support | 2000 |
| Brookside Lodge Management Company Limited | Households | 2006 |
| Brookson (5470G) Limited | Administrative & support | 2007 |
| Brookson (5555G) Limited | Administrative & support | 2007 |
| Brown,Thornton & LEE Independent Financial Advisers LLP | | 2005 |
| BS Property Management (NE) Ltd | Real estate | 2015 |