| Aviationsource Ltd | Information & communication | 2021 |
| AWT Advisory Services Limited | Administrative & support | 2025 |
| B & G Machining Ltd | Manufacturing | 2013 |
| Baby J'S Ltd | Wholesale & retail | 2016 |
| Badger Productions Ltd | Information & communication | 2008 |
| Bago's Breaks Ltd | Wholesale & retail | 2023 |
| Balanced Talent Consulting Ltd | Administrative & support | 2025 |
| Bank on IT (Sales & Distribution) Ltd | Wholesale & retail | 1998 |
| Barrie Highfield & Associates Limited | Financial services | 2000 |
| Bassnett Estates Limited | Real estate | 2004 |
| Battersby Family Company Limited | Real estate | 2017 |
| BC Autos Limited | Wholesale & retail | 2009 |
| Beachley Developments Limited | Construction | 2025 |
| Beachley Investments Limited | Construction | 1991 |
| Beam Denti Spa Limited | Health & social care | 2018 |
| Beaten Metal Limited | Financial services | 2019 |
| Beaufort Dental Care Limited | Health & social care | 2010 |
| Beaufort Square Developments Limited | Real estate | 2020 |
| Bectacular Ltd | Administrative & support | 2016 |
| BED BUG Foundation CIC | Education | 2019 |
| BEE Artistic Ltd | Wholesale & retail | 2025 |
| Beegassafe Ltd | Construction | 2024 |
| Beeston Bloodstock Ltd | Agriculture & fishing | 2024 |
| Bella Coffee Chepstow Ltd | Hospitality | 2022 |
| BEN Brookshaw Dental Laboratory Ltd | Health & social care | 2013 |
| Benjamin Walker Ltd | Financial services | 2023 |
| Bensons Court Management Company Limited | Households | 1990 |
| Berry Therapy Limited | Education | 2022 |
| Berrylands Holdings Limited | Real estate | 2022 |
| Better Together Professional Services Ltd | Professional & scientific | 2017 |
| Bevan-Evans & Capehorn LLP | | 2005 |
| Bevan-Evans Family Law LLP | | 2023 |
| Bialy Transport Ltd | Transport & logistics | 2018 |
| BID Management Limited | Professional & scientific | 2013 |
| Big Lights Group Ltd | Professional & scientific | 2015 |
| Bigkid Animation Ltd | Information & communication | 2025 |
| Biogas Limited | Construction | 2025 |
| Biogas Solutions Limited | Construction | 2013 |
| Biospherics Limited | Professional & scientific | 1989 |
| Birfa Ltd | Other services | 2016 |
| Birkett Homes Limited | Construction | 2003 |
| BJM Building Services Limited | Construction | 2002 |
| BJO Transport Ltd | Transport & logistics | 2020 |
| Black FOX Media R.I. Ltd | Professional & scientific | 2014 |
| Blackmane Developments Ltd | Construction | 2018 |
| Bladen Ltd | Real estate | 2026 |
| Bluebell Barn Ltd | Other services | 2011 |
| Blythe BA Services Ltd | Information & communication | 2026 |
| BNH Property Limited | Real estate | 2023 |
| Boop Solutions Ltd | Information & communication | 2021 |
| Bradley Stoke Wills Ltd | Professional & scientific | 2006 |
| Brads Garden & Property Maintenance Services Ltd | Construction | 2021 |
| Brand Affiniti Limited | Professional & scientific | 2017 |
| Brand Financial Training Limited | Education | 2010 |
| Brand Transport Ltd | Transport & logistics | 2022 |
| Breakfast and Brunch Cafe Ltd | Hospitality | 2018 |
| Breaking Change Ltd | Information & communication | 2025 |
| Breakthroughinnovators Limited | Extraterritorial | 2011 |
| Bristol & Western Properties Ltd. | Real estate | 1929 |
| Bristol Design and Build Home Extensions Ltd | Construction | 2026 |
| Bristol Home Extensions Ltd | Construction | 2026 |
| Bristol Urban Spaces Limited | Hospitality | 2026 |
| Broadfield Court (Kingswood) Management Company Limited | Households | 2005 |
| Broadhall Limited | Real estate | 1997 |
| Broadstone Bloodstock Ltd | Agriculture & fishing | 2026 |
| Brockweir Estates Ltd | Hospitality | 2019 |
| Bronwyn Investment & Development Ltd | Real estate | 2021 |
| Brookes WYE Valley Dairy Co. Limited | Manufacturing | 2000 |
| Broomies Burgers Limited | Hospitality | 2015 |
| Brunel Air Cargo Services Limited | Transport & logistics | 2014 |
| Brunel European Limited | Transport & logistics | 2011 |
| Brunel Shipping & Liner Services (London) Limited | Transport & logistics | 1998 |
| Bryn Haul HAF Limited | Hospitality | 2026 |
| Brynawel Properties Limited | Real estate | 2015 |
| Brynna Property Co. Limited | Construction | 2010 |
| Bubble Events Limited | Administrative & support | 2004 |
| Buildcore Contractors Ltd | Construction | 2025 |
| Bulgarelli Holdings Limited | Real estate | 2025 |
| Bulwark BUS and Coach Engineering Limited | Wholesale & retail | 1992 |
| Bulwark Flava Ltd | Hospitality | 2023 |
| Burnaby Estates Limited | Construction | 2018 |
| Burtonwood DEV. Limited | Construction | 2011 |
| Buttercross Kitchen Limited | Hospitality | 2014 |
| BYW GFB Ltd | Hospitality | 2023 |
| C & a Computer Cover | | 1986 |
| C & B HIS Ltd | Wholesale & retail | 2023 |
| C & D Estate Management Limited | Construction | 2025 |
| C & D Pest Control Ltd | Agriculture & fishing | 2020 |
| Cabnex Limited | Transport & logistics | 2025 |
| Caerwent Garage Ltd | Wholesale & retail | 2012 |
| Cafe on the Hill (Tutshill) Ltd | Hospitality | 2021 |
| Cafe Racer Ville Ltd | Wholesale & retail | 2025 |
| Caldicot Technology Park Limited | Real estate | 2003 |
| Candow Financial Planning Limited | Financial services | 2018 |
| Capra Taxis Ltd | Transport & logistics | 2024 |
| Captivate Gallery Ltd | Wholesale & retail | 2019 |
| Car Tref HAF Limited | Hospitality | 2026 |
| Cardiac Health Diagnostics Limited | Health & social care | 2015 |
| Cardiff Quartz & Marble Ltd | Manufacturing | 2016 |
| Carpenters Arms Shirenewton Ltd | Hospitality | 2025 |