| Buddy Hair Ltd | Other services | 2023 |
| Budget Builders 2 Ltd | Construction | 2020 |
| Budget Carpet & Flooring Centres Limited | Wholesale & retail | 2008 |
| Budget Carpet Holdings Limited | Financial services | 2021 |
| Budget Carpets & Premier Beds Ltd | Wholesale & retail | 2018 |
| Budget Uniform UK Ltd | Wholesale & retail | 2023 |
| Budgie Scrubs CYF. | Manufacturing | 2025 |
| Budo (Wales) Ltd | Transport & logistics | 2016 |
| Budo (Wales) MMA Ltd | Arts & recreation | 2022 |
| Buffer Bros Ltd | Administrative & support | 2024 |
| Bugail Limited | Extraterritorial | 2011 |
| Build 9 Ltd | Real estate | 2018 |
| Build Technology Ltd | Construction | 2026 |
| Building and Proprierties International Limited | Real estate | 2020 |
| Building Blocks G B Limited | Other services | 2018 |
| Building Services Controls 2 Limited | Construction | 2026 |
| Building Services Controls Limited | Construction | 1996 |
| Buildmor Ltd | Construction | 2018 |
| Built Right Building Limited | Construction | 2005 |
| Bulani Electronic Traders Ltd | Wholesale & retail | 2026 |
| Bulb Tech Group Limited | Wholesale & retail | 2020 |
| Bulbastic Engineering Limited | Construction | 2024 |
| Bulk Vending Systems Limited | Other services | 1994 |
| Bullart Graphics Ltd | Administrative & support | 2012 |
| Bullion RUM Limited | Wholesale & retail | 2020 |
| Bulls Properties Ltd | Construction | 2022 |
| Bundlebean Ltd | Manufacturing | 2009 |
| Bunko Limited | Manufacturing | 2010 |
| Burns Property and Letting Ltd | Real estate | 2023 |
| Burrows Caravan Park Limited | Hospitality | 2005 |
| Burton QS Consulting Ltd | Professional & scientific | 2020 |
| Burtys Bar Ltd | Hospitality | 2024 |
| Bush Road Ltd | Real estate | 2025 |
| Business Advice Limited | Real estate | 1986 |
| Business Genie Payments Ltd | Wholesale & retail | 2025 |
| Business Genie Solutions Limited | Administrative & support | 2019 |
| Business Investigations International Ltd | Professional & scientific | 2021 |
| Business Sense Accountancy Services Limited | Extraterritorial | 2015 |
| Business Sense Accountants Limited | Professional & scientific | 2012 |
| Business Sense Associates Limited | Administrative & support | 2013 |
| Business Sense Futures Limited | Extraterritorial | 2018 |
| Business Sense Group Limited | Professional & scientific | 2016 |
| Business Sense Limited | Extraterritorial | 2026 |
| Business Sense Payroll Services Limited | Extraterritorial | 2015 |
| Business Sense Security Limited | Administrative & support | 2019 |
| Business Sense Swansea Limited | Professional & scientific | 2016 |
| Business Sense Training Limited | Education | 2017 |
| Businesssense@Thebusinesscentre Limited | Extraterritorial | 2015 |
| Busters Ltd | Real estate | 2000 |
| Busy Bees Day Nursery Ltd | Education | 2010 |
| Butchers Arms (Alltwen) LLP | | 2023 |
| Butler & Edwards Electrical Services Ltd | Construction | 2017 |
| Butler Precision Engineering Ltd | Manufacturing | 2022 |
| Butter and Sugar Cakes UK Limited | Manufacturing | 2020 |
| Butterfield Morgan Audit Limited | Professional & scientific | 2024 |
| Butterfield Morgan Limited | Professional & scientific | 2000 |
| Button IT Ltd | Information & communication | 2013 |
| Buybuymotor.Com Limited | Wholesale & retail | 2018 |
| Buziness Groww Ltd | Information & communication | 2025 |
| BVS Solutions Ltd | Transport & logistics | 2016 |
| Bwheeler Property Ltd | Real estate | 2019 |
| Bwheeler Surveys Ltd | Professional & scientific | 2024 |
| Bylux Ltd | Administrative & support | 2025 |
| Byng Morris Close Management Limited | Households | 2002 |
| Byrand Limited | Construction | 2022 |
| Byrebeccarandall Ltd | Arts & recreation | 2018 |
| Bytelite Limited | Information & communication | 2020 |
| Bytemedia Limited | Information & communication | 1999 |
| C & D Transport Services Ltd | Transport & logistics | 2003 |
| C & G Auto Repairs Ltd | Wholesale & retail | 2020 |
| C & P High Voltage Services Limited | Manufacturing | 2019 |
| C & R Carpentry Limited | Construction | 2012 |
| C & R James (Property) Limited | Real estate | 2007 |
| C & R James Bakery Limited | Manufacturing | 2020 |
| C & R James Limited | Wholesale & retail | 2003 |
| C & S Commercial Letts Limited | Real estate | 2017 |
| C C M Wields Ltd | Construction | 2023 |
| C COM Accommodation Ltd | Professional & scientific | 2014 |
| C E Daultrey Ltd | Professional & scientific | 2021 |
| C F Bridgewater Limited | Financial services | 2016 |
| C F Bridgewater Property Ltd | Real estate | 2018 |
| C Goodliffe Ltd | Professional & scientific | 2021 |
| C H & V Richards Limited | Real estate | 1998 |
| C J D Heritage Properties Limited | Real estate | 2024 |
| C J Else (South Wales) Limited | Construction | 1981 |
| C K Travel Limited | Transport & logistics | 2013 |
| C M Rees Holdings Ltd | Construction | 2026 |
| C Mcananey Optical Ltd | Health & social care | 2017 |
| C N Evans Plant Hire Ltd | Construction | 2003 |
| C N R Motors Limited | Wholesale & retail | 2025 |
| C N S Power Tools Limited | Wholesale & retail | 2003 |
| C N Sampson Limited | Transport & logistics | 2023 |
| C Projects 22 Ltd | Other services | 2022 |
| C Q Properties Group Limited | Real estate | 2025 |
| C R J Transport Limited | Transport & logistics | 2019 |
| C S Retail Limited | Wholesale & retail | 2003 |
| C S Spinal Healthcare Limited | Health & social care | 2011 |
| C W LAU Limited | Financial services | 2013 |
| C W Robson Safeguarding Limited | Other services | 2017 |
| C Watson Enterprises Ltd | Other services | 2018 |