| Building Space Bristol Limited | Construction | 2019 |
| Building Supplies Solutions Limited | Wholesale & retail | 2015 |
| Building Winners Limited | Professional & scientific | 2017 |
| BUILDLTY99 Ltd | Construction | 2026 |
| Buildpro (U.K.) Ltd | Construction | 2020 |
| Buildro Ltd | Extraterritorial | 2021 |
| Buildserv Contractors Limited | Construction | 2012 |
| Buildsmiths UK Construction Ltd | Construction | 2022 |
| Buildwoorks Ltd | Construction | 2023 |
| Built for More Ltd | Professional & scientific | 2022 |
| Built for This Ltd | Wholesale & retail | 2023 |
| Built Intelligence Ltd | Information & communication | 2012 |
| Built With Distinction Ltd | Real estate | 2024 |
| Bukkyj Limited | Health & social care | 2019 |
| Bulgaria Property Finder Limited | Real estate | 2006 |
| Bulgarian Food Market Ltd | Wholesale & retail | 2014 |
| Bulkbox Card Storage Limited | Wholesale & retail | 2022 |
| Bull Properties Bristol Ltd | Households | 2022 |
| Bull Valour Clothing Ltd | Wholesale & retail | 2025 |
| Bullgod Information Systems Limited | Information & communication | 2017 |
| Bullingham Design Services Limited | Information & communication | 2011 |
| Bullington Press Ltd | Wholesale & retail | 2023 |
| Bullock Car Sales Ltd | Wholesale & retail | 2025 |
| Bullockng Limited | Information & communication | 2021 |
| Bulmac Property Limited | Real estate | 2025 |
| Bulrush Fine Dining Ltd | Hospitality | 2015 |
| Bulstrode Properties Limited | Professional & scientific | 2008 |
| BUM Guns HQ Limited | Wholesale & retail | 2024 |
| Bumble BEE Accountancy Ltd | Professional & scientific | 2014 |
| Bump Club Limited | Arts & recreation | 2006 |
| Bump to Cradle Ltd | Education | 2016 |
| Bumpkin Organics Ltd | Manufacturing | 2020 |
| Bumps Accident Repair Centre Ltd | Extraterritorial | 2022 |
| BUN BAO Ltd | Hospitality | 2025 |
| Buna Food Ltd | Hospitality | 2025 |
| Bundy & Bond Estate Agents Limited | Real estate | 2015 |
| Bundy Bond & Chapman Lettings Limited | Real estate | 2017 |
| Bunescu Dent Ltd | Health & social care | 2022 |
| Bunescu Development Ltd | Real estate | 2023 |
| Bunescu Larkhall Ltd | Wholesale & retail | 2021 |
| Bungiehd Ltd | Information & communication | 2014 |
| Bunker Partners LP | | 2011 |
| Bunkersonix Limited | Arts & recreation | 2010 |
| Bunn Holidays Ltd | Hospitality | 2007 |
| Buntington Green Energy Centre Ltd | Energy | 2022 |
| Buontempo Consulting Limited | Administrative & support | 2009 |
| Bupa Dental Services Limited | Health & social care | 1950 |
| Bupard Limited | Wholesale & retail | 2023 |
| Buraq Transfers Ltd | Transport & logistics | 2023 |
| Burbage Joinery Limited | Extraterritorial | 2011 |
| Burchill Construction & Development Ltd | Construction | 2020 |
| Burchills Online Ltd | Wholesale & retail | 2022 |
| Burden Neurological Institute (the) | Health & social care | 1970 |
| Bureau Esprit Ltd | Professional & scientific | 2026 |
| Burford Alpha Limited | Professional & scientific | 2003 |
| Burford Beta Holdings Limited | Professional & scientific | 2003 |
| Burford Beta Limited | Real estate | 2003 |
| Burford Carrington Limited | Real estate | 2000 |
| Burford Delta Limited | Real estate | 2003 |
| Burford Epsilon | Administrative & support | 2003 |
| Burford Estate & Property Co. Limited | Real estate | 1986 |
| Burford Management Limited | Professional & scientific | 2006 |
| Burford Zeta | Professional & scientific | 2004 |
| Burford ZZ Limited | Financial services | 2001 |
| Burgar GUY Bristol Limited | Hospitality | 2024 |
| Burger Rush Ltd | Hospitality | 2024 |
| Burger Theory Birmingham Limited | Hospitality | 2018 |
| Burger Theory Bristol Limited | Hospitality | 2017 |
| Burger Theory Ltd | Hospitality | 2023 |
| Burger Vice Ltd | Hospitality | 2023 |
| Burges Salmon Company Limited | Administrative & support | 2011 |
| Burges Salmon LLP | | 2004 |
| Burges Salmon Pension Trustees Limited | Professional & scientific | 2008 |
| Burges Salmon Services Limited | Professional & scientific | 2001 |
| Burges Salmon Trustees Limited | Administrative & support | 2000 |
| Burgess & Beech Ltd | Professional & scientific | 2015 |
| Burgess Green Ltd | Hospitality | 2017 |
| Burgess IT Consulting Ltd | Information & communication | 2013 |
| Burgess Kitchens and Carpentry Limited | Construction | 2023 |
| Burgess Masonry Limited | Construction | 2019 |
| Burgess Projects Limited | Construction | 2018 |
| Burgh Recruitment Limited | Administrative & support | 2017 |
| Burghel Express Limited | Transport & logistics | 2019 |
| Buried Giants Ltd | Information & communication | 2023 |
| Burke & Marshall Ltd | Manufacturing | 2015 |
| Burke Management Company Ltd | Real estate | 2010 |
| Burkestone Properties Ltd | Real estate | 2025 |
| Burleigh Advocates Limited | Professional & scientific | 2015 |
| Burleigh Consultancy & Management Ltd | Professional & scientific | 2026 |
| Burleigh Investment & Holdings Limited | Financial services | 2023 |
| Burleigh Park Property Investments Ltd | Real estate | 2019 |
| Burleigh Partnership Limited | Real estate | 2025 |
| Burleigh Property Ltd | Real estate | 2019 |
| Burley Hall Media Limited | Information & communication | 2015 |
| Burley News Limited | Wholesale & retail | 2018 |
| Burlington Heamingway Limited | Administrative & support | 2025 |
| Burmisk Ltd | Health & social care | 2022 |
| Burn Design Ltd | Professional & scientific | 2019 |
| Burnbridge Services Limited | Manufacturing | 2017 |
| Burnell Estates Limited | Professional & scientific | 1962 |