| Brand New Living Mossley Ltd | Real estate | 2019 |
| Brand Progression Limited | Wholesale & retail | 1998 |
| Brand Street Market Ltd | Manufacturing | 2019 |
| Brand Verve Limited | Professional & scientific | 2025 |
| Brand-Wallis Limited | Real estate | 1987 |
| Brandborn Capital Ltd | Manufacturing | 2019 |
| Brandcontent Ltd | Professional & scientific | 2021 |
| Brandcove Limited | Professional & scientific | 2025 |
| Branded Brolly Limited | Wholesale & retail | 2025 |
| Brandelier Collective Limited | Professional & scientific | 2025 |
| Brandforge Commerce Ltd | Wholesale & retail | 2026 |
| Brandlaunch Ltd | Information & communication | 2023 |
| Brandora Agency Ltd | Information & communication | 2025 |
| BRANDPLAY3.0 Ltd | Hospitality | 2025 |
| Brandshop (UK) Limited | Wholesale & retail | 1998 |
| Brandsluanch Ltd | Wholesale & retail | 2021 |
| Brandynamics Ltd | Other services | 2017 |
| Brandzenith Ltd | Information & communication | 2025 |
| Branivox Ltd | Wholesale & retail | 2025 |
| Branowa Ltd | Wholesale & retail | 2025 |
| Branvect Ltd | Professional & scientific | 2025 |
| Branwen Gwyn CYF | Professional & scientific | 2023 |
| Brar Cardiff Ltd | Manufacturing | 2026 |
| Brass PIG Properties Limited | Real estate | 2024 |
| Brav Custom Ltd | Wholesale & retail | 2026 |
| Brava Management Ltd | Administrative & support | 2017 |
| Bravata Limited | Administrative & support | 2011 |
| Brave Investments Ltd | Real estate | 2014 |
| Brave Rave Events Ltd | Arts & recreation | 2022 |
| Braveheart (Scotland) Limited | Information & communication | 2010 |
| Bravelyo Ltd | Education | 2025 |
| Braventis Ltd | Administrative & support | 2011 |
| Bravitsia Consulting Ltd | Professional & scientific | 2024 |
| Bravo Deal Ltd | Wholesale & retail | 2021 |
| Bravo Recruitment Services Limited | Administrative & support | 2017 |
| Bravura Foods Limited | Wholesale & retail | 2010 |
| Bravura Holdings Ltd | Financial services | 2024 |
| Braynix Limited | Professional & scientific | 2025 |
| Brazers Engines Limited | Wholesale & retail | 2026 |
| Brazilian Gemstones Ltd | Wholesale & retail | 2016 |
| BRB Construction Ltd | Construction | 2019 |
| BRC Limited | Manufacturing | 2008 |
| BRD International Trade Co. Limited | Wholesale & retail | 2017 |
| Bread & Salt Ltd | Hospitality | 2016 |
| Bread of Devon Ltd | Hospitality | 2025 |
| Break-Point Academy Ltd | Education | 2020 |
| Breakfast of Champions Limited | Information & communication | 2026 |
| Breaking Brands Management Ltd | Professional & scientific | 2022 |
| Breakit Ltd | Wholesale & retail | 2024 |
| Breakthrough Theatre Arts C.I.C. | Education | 2021 |
| Brean Family Leisure Park Limited | Professional & scientific | 2014 |
| Brean Theme Park Holdings Limited | Real estate | 2020 |
| Breana Group Ltd | Real estate | 2025 |
| Breast Cancer Therapeutics Ltd | Professional & scientific | 2024 |
| Breathe Branding Ltd | Administrative & support | 2021 |
| Breathe Promotions Ltd | Financial services | 2014 |
| Brebe Limited | Wholesale & retail | 2011 |
| Breckland Retail Services Ltd | Wholesale & retail | 2017 |
| Brecon Street Motors Ltd | Wholesale & retail | 2026 |
| Brecongate Projects Ltd. | Construction | 1995 |
| Breddos Events Limited | Hospitality | 2014 |
| Breddos Stokey Ltd | Hospitality | 2023 |
| Breen Grey Ltd | Wholesale & retail | 2019 |
| Breeny LEE Ltd | Arts & recreation | 2019 |
| Breez Marketing Ltd | Transport & logistics | 2025 |
| Breeze Beverages Ltd | Wholesale & retail | 2017 |
| Breeze Box Limited | Wholesale & retail | 2025 |
| Breeze Labour Supply Ltd | Construction | 2017 |
| Breeze Work Solutions Ltd | Administrative & support | 2025 |
| Breezybee Ltd | Wholesale & retail | 2025 |
| Breichiau HIR Ltd | Arts & recreation | 2023 |
| Brellen Ltd | Wholesale & retail | 2025 |
| Bremleycourt Limited | Households | 1972 |
| Bren Building Limited | Construction | 2021 |
| Brendmo Accountants Ltd | Professional & scientific | 2021 |
| Brenin Limited | Wholesale & retail | 2025 |
| Brent Commodity Traders Limited | Professional & scientific | 2020 |
| Brenta International PC | | 2019 |
| Brentarch Limited | Hospitality | 1998 |
| Brentmark Limited | Financial services | 2012 |
| Brentto Industry (UK) Ltd | Administrative & support | 2014 |
| Brett Michael Engineering Ltd | Professional & scientific | 2024 |
| Brew Lounge Limited | Wholesale & retail | 2022 |
| Brew Wilnecote Ltd | Hospitality | 2026 |
| Brewberry Cafe & Resto Ltd | Hospitality | 2025 |
| Brewed Awakening Ltd | Hospitality | 2026 |
| Brewer Consultancy Cardiff Ltd | Other services | 2023 |
| Brewery Court Management Company Limited | Real estate | 2006 |
| Brexia Ltd | Wholesale & retail | 2025 |
| Brezo Global Ltd | Wholesale & retail | 2026 |
| Brght Pine Saas Tech Ltd | Information & communication | 2025 |
| Brgr & Shakes Ltd | Hospitality | 2021 |
| BRI. Inst. of Economics and Political Science Ltd | Education | 2017 |
| Brian Harries Building Ltd | Construction | 2022 |
| Brian Jones Carpentry Limited | Manufacturing | 2026 |
| Brian Jones Engineering Ltd | Extraterritorial | 2023 |
| Brian Macentee Architecture & Design Limited | Professional & scientific | 2012 |
| Brian Robson Contracts Limited | | 1947 |
| Brianne Commercial Limited | Real estate | 2026 |
| Brianne Estates Ltd | Real estate | 2024 |