| Brandscope Ltd | Information & communication | 2021 |
| Branksmere Studio Ltd | Professional & scientific | 2024 |
| Bransbury Park Cafe Limited | Hospitality | 2020 |
| Brashfield Investments Limited | Financial services | 2020 |
| Brassfile Ltd | Construction | 2018 |
| Brausen Limited | Real estate | 2025 |
| Brave Martial Arts Ltd | Professional & scientific | 2023 |
| Bravo November Limited | Manufacturing | 2023 |
| Breach Farm Management Company Limited | Real estate | 2024 |
| Brett Haley FX Limited | Construction | 2023 |
| Brew & Clue Publishing Ltd | Information & communication | 2025 |
| Brew Revolution Ltd | Hospitality | 2024 |
| Brewhouse Developments Limited | Construction | 2025 |
| Brian Mabe Fire Protection Ltd | Construction | 2016 |
| Brick Revival Limited | Administrative & support | 2017 |
| Brickmakers Developments Limited | Construction | 2024 |
| Bricktex Southern Limited | Construction | 2022 |
| Bridge and Branson Ltd | Manufacturing | 2016 |
| Bridge Cafe Ltd | Hospitality | 2018 |
| Bridge Joinery Limited | Manufacturing | 2022 |
| Bridle Transport Limited | Administrative & support | 2011 |
| Bright Fruit Ltd | Wholesale & retail | 2017 |
| Bright Technology Ltd | Construction | 2003 |
| Bright Vision Care Ltd | Health & social care | 2024 |
| Brighton Court Limited | Wholesale & retail | 1998 |
| Brightside Systems Limited | Information & communication | 2003 |
| Brightsparkz 24/7 Limited | Construction | 2018 |
| Brightway Global Services Limited | Administrative & support | 2021 |
| Brilliant Blinds Limited | Wholesale & retail | 2002 |
| Brilliant BLU Ltd | Professional & scientific | 2012 |
| Brilliant Doors and Windows Ltd | Construction | 2024 |
| Brima Group Limited | Transport & logistics | 2025 |
| Brimington Property Limited | Real estate | 2023 |
| Brinco Limited | Financial services | 2008 |
| Brindabella Investments Limited | Real estate | 2018 |
| Brindley Machinery Moving Limited | Transport & logistics | 2020 |
| Bring IT Back Into Britain Limited | Manufacturing | 2020 |
| BRIP0319 (Kidbrook Send) LLP | | 2020 |
| BRIP0319 (Kidbrook Wimbledon) LLP | | 2019 |
| BRIP0918 (Tongham) LLP | | 2019 |
| Briskcoffee Ltd | Hospitality | 2026 |
| Brit Teak Furniture Limited | Manufacturing | 2023 |
| Britannia Master Locksmiths Ltd | Administrative & support | 2006 |
| Britpip Limited | Information & communication | 2012 |
| BRM Computers Limited | Information & communication | 2012 |
| BRO Hose Ltd | Financial services | 2024 |
| Broadside Training Limited | Education | 2010 |
| Broadsword Air Ambulance Ltd | Manufacturing | 2025 |
| Broadsword Helicopters Ltd | Manufacturing | 2025 |
| Broadway Civils Ltd | Construction | 2026 |
| Brockenhurst Rest Home Limited | Health & social care | 2009 |
| Brockhampton Developments Limited | Construction | 2024 |
| Broissance Ltd | Transport & logistics | 2026 |
| Broken Studios Limited | Information & communication | 2019 |
| Broker Alexander Limited | Financial services | 2018 |
| Brolin Roofing and Building Ltd | Construction | 2025 |
| Brook Lane Rest Home Limited | Health & social care | 2007 |
| Brook LEA Management Limited | Real estate | 2017 |
| Brookfield Data Comms Ltd | Information & communication | 2015 |
| Brookley Properties Limited | Real estate | 2019 |
| Brooklyn Medical Ltd | Health & social care | 2023 |
| Brookscapes Landscaping Limited | Administrative & support | 2018 |
| Browins Ltd | Real estate | 2017 |
| Brown Onion Books Ltd | Wholesale & retail | 2025 |
| Brown Spice Limited | Hospitality | 2016 |
| Broxmead Limited | Households | 1985 |
| BRS Property Developments Ltd | Real estate | 2025 |
| Brunel Health Network PCN Limited | Health & social care | 2023 |
| Brunsdon Mechanical Services Ltd | Construction | 2019 |
| Bryburn Fire Protection Ltd | Construction | 2024 |
| Bryburn Holdings Limited | Financial services | 2021 |
| Bryburn Homes Ltd | Construction | 2025 |
| Bryburn Investments Ltd | Financial services | 2025 |
| Bryburn Limited | Construction | 2014 |
| Brynwell (Southern) Limited | Construction | 2009 |
| Brynwell Limited | Construction | 2024 |
| BS Burgers Ltd | Hospitality | 2021 |
| BS4 Approvers Ltd | Professional & scientific | 2026 |
| BS4 Group Ltd | Professional & scientific | 2026 |
| Bsgd Properties Ltd | Real estate | 2022 |
| BSL Scaffolding Services Limited | Construction | 2024 |
| BSS Companies Ltd | Wholesale & retail | 2025 |
| BSS Enterprise Solution Ltd | Manufacturing | 2023 |
| BSS Solution Accounting & Bookkeeping Ltd | Professional & scientific | 2022 |
| BSS Solution Legal & Insolvency Ltd | Professional & scientific | 2022 |
| BSV Consultancy Services Limited | Professional & scientific | 2015 |
| BT Commercial Cleaning Ltd | Administrative & support | 2022 |
| BT Energy Solutions Limited | Public administration | 2020 |
| BTG Bathrooms Ltd | Construction | 2025 |
| BTR Carpentry & Joinery Ltd | Manufacturing | 2022 |
| BTW Property Services Ltd | Construction | 2025 |
| BTY by Kimberley Ltd | Other services | 2018 |
| BTY Co Supplied Ltd | Other services | 2025 |
| Buahkuli Ltd | Hospitality | 2021 |
| Bubble Citea Ltd | Wholesale & retail | 2019 |
| Bubble City Ltd | Wholesale & retail | 2013 |
| Bucas Store Limited | Wholesale & retail | 2024 |
| Buckingham Pubs Limited | Hospitality | 2010 |
| Bucknall Family Catering Limited | Hospitality | 2017 |
| Buckwells of Southsea Limited | Wholesale & retail | 2002 |