| Blades Cost Engineering Limited | Professional & scientific | 2007 |
| Blakemore Property Group Ltd | Real estate | 2025 |
| Blankt Ltd | Professional & scientific | 2021 |
| Blanq Sheet 2 Limited | Other services | 2025 |
| Blanq Sheet Limited | Wholesale & retail | 2021 |
| Blendings Limited | Manufacturing | 2013 |
| Blenheim Court Properties Limited | Real estate | 1993 |
| Blessed Solutions Ltd | Health & social care | 2013 |
| Blind Tiger CIC | Arts & recreation | 2023 |
| Blingtandoor Ltd | Wholesale & retail | 2026 |
| Blissfusion Limited | Other services | 2025 |
| BLN Design Services Limited | Professional & scientific | 2001 |
| Blondie Bakery (Norton) Ltd | Wholesale & retail | 2023 |
| Blondie Bakery Ltd | Financial services | 2023 |
| BLOSSOM1BEAUTY Ltd | Other services | 2025 |
| Blue Deer Properties (North East) Ltd | Real estate | 2022 |
| Blue Falcon Consultancy Ltd | Information & communication | 2016 |
| Blue House Point Limited | Manufacturing | 1962 |
| Blue Light Escapes Group Ltd | Administrative & support | 2022 |
| Blue Light Escapes Ltd | Administrative & support | 2025 |
| Blue Light Escapes Travel Ltd | Administrative & support | 2025 |
| Blue Red Blue LLP | | 2025 |
| Blueridge Inspection Ltd | Professional & scientific | 2011 |
| Bluetail Services Ltd | Administrative & support | 2024 |
| Bluewater Engineering Limited | Professional & scientific | 2018 |
| BME Performance Ltd | Wholesale & retail | 2024 |
| BNS Convenience Store Ltd | Wholesale & retail | 2021 |
| Bob’S Dog Lodge Ltd | Other services | 2026 |
| Bockle Limited | Wholesale & retail | 2023 |
| Body 2 Fit Limited | Health & social care | 2007 |
| Body Shop Stockton Ltd | Wholesale & retail | 2019 |
| Boem Leisure Limited | Other services | 2017 |
| Boiler Force Teesside Ltd | Construction | 2023 |
| Bolam Cleaning Services Ltd | Administrative & support | 2016 |
| Bolero Holidays Italy Ltd | Administrative & support | 2019 |
| Bolero Holidays Ltd | Administrative & support | 2014 |
| Bomats Ltd | Health & social care | 2022 |
| Bone Street Auto Repair Ltd | Wholesale & retail | 2019 |
| Bontex & Luis Inc Ltd | Real estate | 2016 |
| Bonuscrest Limited | Professional & scientific | 2008 |
| Bookkeeping 4 Busy Bees Limited | Professional & scientific | 2014 |
| Boomerang Welding Services Ltd | Manufacturing | 2025 |
| Boomerangar Ltd | Wholesale & retail | 2022 |
| Boosted EGO Ltd | Other services | 2026 |
| Booth (NE) Limited | Transport & logistics | 2023 |
| Boots & Beyond Ltd | Arts & recreation | 2025 |
| Boro Blinds Ltd | Manufacturing | 2016 |
| Boro Flooring Solutions Ltd | Administrative & support | 2017 |
| Boroughbridge Properties Ltd | Real estate | 2011 |
| Bosward & Bonnard Search Co Limited | Professional & scientific | 2025 |
| Botsokoy Limited | Construction | 2024 |
| Boutgas Heating Services Limited | Construction | 2023 |
| Boutique Sweets Limited | Wholesale & retail | 2023 |
| Bowburn Healthcare Ltd | Health & social care | 2021 |
| Bowesfield DRY Cleaners Limited | Other services | 2024 |
| Bowesfield News Ltd | Wholesale & retail | 2021 |
| Bowey Properties Ltd | Real estate | 2021 |
| Bowles Commercial Holdings Ltd | Real estate | 2024 |
| BOX12 Global Ltd | Other services | 2019 |
| Boxit Storage Ltd | Other services | 2024 |
| BP Project Services Ltd | Professional & scientific | 2026 |
| Bradbury Inspection Limited | Professional & scientific | 2012 |
| Braddec Ltd | Other services | 2015 |
| Bradley Homes Ltd | Real estate | 2025 |
| Bradley Plumbing & Heating Ltd | Construction | 2018 |
| Branchly Limited | Information & communication | 2026 |
| Brand Direct Services Ltd | Wholesale & retail | 2023 |
| BRB Education Ltd | Professional & scientific | 2022 |
| Breach EOD Services Ltd | Professional & scientific | 2024 |
| Breakout Media Ltd | Professional & scientific | 2018 |
| Brelie Ltd | Wholesale & retail | 2022 |
| Brentwood IT Consulting Ltd | Professional & scientific | 2014 |
| Brian Cunningham Site Services Ltd | Construction | 2015 |
| Brian's Technical Services Limited | Information & communication | 2012 |
| Briarcroft Services Ltd | Professional & scientific | 2022 |
| Bridge Learning Centre CIC | Education | 2024 |
| Bridge Street Mews Management Company Limited | Households | 2004 |
| Bridgehill Day Service Ltd | Health & social care | 2013 |
| Bridgman IBC Limited | Manufacturing | 2004 |
| Bright Ideas Limited | Real estate | 2008 |
| Brilliant Health Care Services Ltd | Health & social care | 2023 |
| Britannia Electrical Systems Limited | Construction | 2024 |
| Britannia Square Limited | Wholesale & retail | 2020 |
| Brittains Electrical Services Ltd | Construction | 2024 |
| Brittany Scents Limited | Wholesale & retail | 2025 |
| Britton & Robson Limited | Wholesale & retail | 2007 |
| Brix Banx & Management Ltd | Transport & logistics | 2019 |
| Broadgate Wealth Client Servicing LLP | | 2018 |
| Brokersync Ltd | Financial services | 2025 |
| Brolga Limited | Professional & scientific | 2018 |
| Brompton House Consultants Ltd | Professional & scientific | 2017 |
| Bronze Boutique Stokesley Ltd | Wholesale & retail | 2026 |
| Brook Heating and Plumbing Ltd | Construction | 2025 |
| Brookcrest Limited | Professional & scientific | 2016 |
| Brooks Holdings (North East) Limited | Financial services | 2018 |
| Brookson (5627C) Limited | Administrative & support | 2007 |
| Brooktroop Limited | Other services | 1991 |
| Broom Hill Clinic Limited | Health & social care | 2018 |
| Brownmoor Kitchen Ltd | Hospitality | 2024 |
| Browns Safety Services Limited | Public administration | 2019 |