| Boggled Ltd | Information & communication | 2025 |
| Bohemian Bazaar Limited | Manufacturing | 2025 |
| Boiler Services Engineers Limited | Construction | 2024 |
| Bold Apartments 2 Ltd | Real estate | 2025 |
| Bold Apartments Ltd | Real estate | 2024 |
| Bold Online Marketing Ltd | Administrative & support | 2021 |
| Bold Street Management Co. Limited | Households | 2007 |
| Bolder Homes Limited | Real estate | 2015 |
| Bolt Group Ltd | Construction | 2022 |
| Bolt the Bird Ltd | Wholesale & retail | 2025 |
| Bolton Birch (Chester) Limited | Professional & scientific | 2016 |
| Bolton Tibbs Limited | Wholesale & retail | 2025 |
| BON VOY Medicals Ltd | Health & social care | 2021 |
| Bond Avenue Capital Limited | Real estate | 2019 |
| Bond Property Management Company Limited | Households | 2023 |
| Bonnied Limited | Health & social care | 2023 |
| Bonum Ideas South Wales Ltd | Professional & scientific | 2018 |
| Boomtastic Fireworks Limited | Wholesale & retail | 2024 |
| Boost Studios Limited | Professional & scientific | 2024 |
| Booted Limited | Professional & scientific | 2020 |
| Boowm Ltd | Information & communication | 2019 |
| Border and Bridges Limited | Wholesale & retail | 2022 |
| Border Grace Consulting Limited | Professional & scientific | 2018 |
| Born to Bake Limited | Manufacturing | 2022 |
| Boromir House Limited | Real estate | 2009 |
| Borough Aerospace Limited | Manufacturing | 2017 |
| Borrowdale Manton Developments Ltd | Construction | 2025 |
| Boss Places Ltd | Hospitality | 2023 |
| Bossman Properties Limited | Real estate | 2019 |
| Boston Wealth Management Ltd | Financial services | 2012 |
| Botanica Garden Design Ltd | Administrative & support | 2005 |
| Botes Group Limited | Wholesale & retail | 2025 |
| Bouaka Limited | Real estate | 2023 |
| Boult Properties Ltd | Real estate | 2020 |
| Boulton Restaurant Group Limited | Hospitality | 2023 |
| Boulton Warehouse Ltd | Real estate | 2022 |
| Bound Logic Limited | Information & communication | 2021 |
| Boundary Court Management Company Limited | Real estate | 2002 |
| Bourne Boutique Ltd | Wholesale & retail | 2022 |
| Bourne Ready Ltd | Manufacturing | 2026 |
| Bowcrest Limited | Construction | 1963 |
| Bowker Investments Limited | Real estate | 2019 |
| Box Office Creator Ltd | Information & communication | 2026 |
| Boydies Ltd | Real estate | 2024 |
| BP Property NW Ltd | Real estate | 2025 |
| BPD Mechanic Ltd | Wholesale & retail | 2025 |
| BPM OPS Ltd | Professional & scientific | 2025 |
| Bpuzzled Ltd | Real estate | 2013 |
| Bradshaw Farnham LEA Limited | Real estate | 2003 |
| Braecroft Landscapes Limited | Administrative & support | 2014 |
| Braeside Management (Ambleside) Limited | Real estate | 1998 |
| Braid Consulting Ltd | Professional & scientific | 2025 |
| Bramag Ltd | Information & communication | 2014 |
| Bramerton Court Management Limited | Real estate | 1986 |
| Bramhalls Limited | Professional & scientific | 2009 |
| Brand Adhd Services Limited | Health & social care | 2024 |
| Brand Mark Franchising Ltd | Professional & scientific | 2014 |
| Brand Nubian Ltd | Wholesale & retail | 2026 |
| Brandflake Design Ltd | Professional & scientific | 2022 |
| Brantec Limited | Information & communication | 2018 |
| Brantley Properties Limited | Real estate | 1996 |
| Braum VENUE2 Ltd | Hospitality | 2026 |
| Brave Lash Limited | Other services | 2020 |
| Bravo Associates Limited | Professional & scientific | 2015 |
| Bravo Catering Limited | Hospitality | 2025 |
| Breach Apparel Ltd | Wholesale & retail | 2018 |
| Breach Culture Ltd | Wholesale & retail | 2025 |
| Breathe Normally Limited | Health & social care | 2019 |
| Breck House Management Limited | Households | 2026 |
| Breckfield Ltd | Construction | 2019 |
| Bremers Ltd | Professional & scientific | 2025 |
| Brendan Bilton Consulting Limited | Administrative & support | 2010 |
| Brendan James Consulting Ltd | Professional & scientific | 2023 |
| Brennan Homes Ltd | Real estate | 2024 |
| Brex Group Ltd | Wholesale & retail | 2025 |
| Brick Investments Limited | Real estate | 2015 |
| Brickworksolutions Limited | Construction | 2009 |
| Brident Services Ltd | Professional & scientific | 2011 |
| Bridge Automotive Limited | Wholesale & retail | 2005 |
| Bridge Financial Services Limited | Professional & scientific | 2026 |
| Bridgeway Living Group Ltd | Wholesale & retail | 2026 |
| Bridpoint Management Ltd | Real estate | 2014 |
| Bridport (Liverpool) Management Company Limited | Real estate | 2005 |
| Bridscape Ltd | Construction | 2005 |
| Bright Car Finance Limited | Financial services | 2020 |
| Bright Sales Ltd | Wholesale & retail | 2018 |
| Bright Spot Reports Limited | Health & social care | 2025 |
| Brighter Bloom Healthcare Group (Northwest) Limited | Health & social care | 2025 |
| Brighter Bloom Healthcare Group Ltd | Health & social care | 2021 |
| Brighter Futures School Limited | Education | 2025 |
| Brightscene Media Limited | Information & communication | 2010 |
| Brightwell Travel Ltd | Administrative & support | 2025 |
| Brisbane Projects Limited | Information & communication | 2021 |
| Bristow Building Company Ltd | Construction | 2017 |
| Britannia Asset Management Limited | Real estate | 2021 |
| Britannia Corp Limited | Other services | 2020 |
| Britannia Management Consultant Ltd | Professional & scientific | 2020 |
| Brite Point Ltd | Administrative & support | 2025 |
| British Self Defence Governing Body Limited | Education | 1992 |
| Britton Interpreting Limited | Other services | 2017 |