| Bluesteel (Bath) Limited | Construction | 2011 |
| Bluestripe Consulting Ltd | Professional & scientific | 2018 |
| Blush Talent Management Limited | Arts & recreation | 2023 |
| Bluskye Property Limited | Real estate | 2024 |
| BM Data Visualisation Limited | Information & communication | 2019 |
| BM Holdings 365 Limited | Construction | 2023 |
| BM Lewis Limited | Wholesale & retail | 2011 |
| BML Digital Ltd | Information & communication | 2017 |
| BNG Plus Ltd | Professional & scientific | 2025 |
| BNX South West Ltd | Professional & scientific | 2010 |
| Board Lines Ltd | Other services | 2022 |
| Boardlife Ltd | Professional & scientific | 2019 |
| BOB AI Ltd | Professional & scientific | 2024 |
| BOB Fairclough and Associates Ltd | Professional & scientific | 2018 |
| Bobby MAK Hair Limited | Other services | 2009 |
| Bobo Tails Books Limited | Information & communication | 2016 |
| Boca Teamwear Ltd | Wholesale & retail | 2009 |
| Bock Works Limited | Manufacturing | 2018 |
| Body Mind and Soul Therapy Limited | Other services | 2024 |
| Bodywork Limited | Wholesale & retail | 1987 |
| Bogus Ltd | Wholesale & retail | 2025 |
| Boilerforce Heating Services Ltd | Construction | 2023 |
| Boilers and Bathrooms (SW) Limited | Construction | 2017 |
| Bokeh and Bloom Ltd | Administrative & support | 2022 |
| Bokk Group Ltd | Construction | 2024 |
| Bokks Enterprise Limited | Real estate | 2002 |
| Bold Environmental Limited | Professional & scientific | 2011 |
| Bollywood Foods Limited | Manufacturing | 2003 |
| Bolt Designs Ltd | Professional & scientific | 2020 |
| Bolt Holdings Limited | Financial services | 2024 |
| Bolt-On Marketing Ltd | Administrative & support | 2019 |
| Bolwell Hair Ltd | Other services | 2022 |
| Bombay Balti Limited | Hospitality | 2004 |
| Bond O'Seven Ltd | Financial services | 2014 |
| Bond One Europe Limited | Professional & scientific | 2013 |
| Bonfire Hill Limited | Wholesale & retail | 2006 |
| Bonhill Estates Limited | Extraterritorial | 2022 |
| Bonivil Ventures Ltd | Real estate | 2023 |
| Bonnett Carpentry Limited | Construction | 2017 |
| Bonneybond Limited | Real estate | 1993 |
| Bonuchi Ltd | Construction | 2022 |
| Bookingstream Ltd | Professional & scientific | 2025 |
| Books Beautiful Limited | Information & communication | 2024 |
| Bootstrap Systems Limited | Information & communication | 2008 |
| Bopd Ltd | Real estate | 2023 |
| Born Health Ltd | Professional & scientific | 2012 |
| Born to Chun Limited | Real estate | 2023 |
| Borrum Belenus (UK) Limited | Professional & scientific | 2024 |
| Bosk Interiors Ltd | Wholesale & retail | 2026 |
| Bossa Accessories Ltd | Wholesale & retail | 2025 |
| Bossington Hall Limited | Hospitality | 2016 |
| Bosworth Ltd | Professional & scientific | 2022 |
| Botanee Asset Limited | Real estate | 2021 |
| Boulders Community Housing CIC | Hospitality | 2026 |
| Bourne Legal Costs Limited | Other services | 2002 |
| Boutique Block Management Limited | Real estate | 2023 |
| Boutique Blocks Limited | Real estate | 2025 |
| Bowen Renovare Limited | Real estate | 2023 |
| Bowerbird Consulting Ltd | Construction | 2023 |
| Bowerhouse Bath Ltd | Administrative & support | 2016 |
| Bowers Associates Ltd | Education | 2012 |
| Bowie Live Ltd | Arts & recreation | 2022 |
| Bowimi Limited | Information & communication | 2018 |
| Bownham Mead Mortgages Ltd | Financial services | 2025 |
| Bowrey Future Proofing Ltd | Financial services | 2023 |
| Boxchamps Ltd | Arts & recreation | 2025 |
| Boxlock Engineering Limited | Mining & quarrying | 2011 |
| Boydside Ltd | Agriculture & fishing | 2017 |
| BP Consulting Services Ltd | Administrative & support | 2025 |
| BP Play Cafe Ltd | Hospitality | 2026 |
| BPD Group Holdings Limited | Financial services | 2024 |
| BPD Joinery Limited | Construction | 2023 |
| BPM Contracting Services Limited | Construction | 2005 |
| BPM Land Holdings Limited | Real estate | 2021 |
| BQM Consulting Limited | Professional & scientific | 2006 |
| Brabazon Enterprises Limited | Real estate | 2025 |
| Brabazon Estates Limited | Real estate | 2019 |
| Bracken Inc Limited | Information & communication | 2025 |
| Brad Abrahams Limited | Health & social care | 2006 |
| Bradley & Co (Bristol) Limited | Real estate | 2015 |
| Bradley Property Maintenance Ltd | Construction | 2021 |
| Bradlok Engineering Ltd | Professional & scientific | 2020 |
| Bradshaw & Co Limited | Professional & scientific | 2012 |
| Brahamos Limited | Hospitality | 2017 |
| Brain's Foto Guides Limited | Information & communication | 2017 |
| Brainforest Limited | Wholesale & retail | 2017 |
| Brainprint Limited | Professional & scientific | 2010 |
| Brainx Movement SP Ltd | Other services | 2025 |
| Bramble Eight Ltd | Financial services | 2020 |
| Bramble Hedge Farm Limited | Real estate | 2017 |
| Bramhall Estates (Bath) Limited | Real estate | 1996 |
| Bramhall Homes Limited | Construction | 2016 |
| Bramley Developments (Bath) Limited | Construction | 2014 |
| Bramshill Investments Ltd | Real estate | 2008 |
| Brand & JEB Holdings Ltd | Financial services | 2025 |
| Brand Flow Ltd | Professional & scientific | 2025 |
| Brandappropos Limited | Professional & scientific | 2016 |
| Branded & Unstoppable Ltd | Professional & scientific | 2023 |
| Brandguard Ltd | Extraterritorial | 2025 |
| Brass Tacks Limited | Health & social care | 1988 |