| Butetown Artists | Arts & recreation | 1997 |
| Butetown Arts and Culture CIC | Arts & recreation | 2023 |
| Butetown Community Leisure Ltd | Arts & recreation | 2016 |
| Buthsku Ltd | Wholesale & retail | 2021 |
| Butik Limited | Wholesale & retail | 2020 |
| Butkus Limited | Transport & logistics | 2013 |
| Butlin Consulting Limited | Professional & scientific | 2014 |
| Butt Merchant Ltd | Wholesale & retail | 2025 |
| Buttar Stores Limited | Wholesale & retail | 2016 |
| Butterbowl Hotel Leeds Ltd | Hospitality | 2014 |
| Buttercup I.T Limited | Other services | 2001 |
| Buttercups Day Nursery UK Limited | Education | 2009 |
| Butterflet Ltd | Real estate | 2022 |
| Butterfly Brunch Ltd | Extraterritorial | 2020 |
| Butterfly Coach Limited | Health & social care | 2024 |
| Butterfly Data Trustees Limited | Extraterritorial | 2021 |
| Butterfly Day Nursery Limited | Education | 2017 |
| Butterfly Projects Ltd | Information & communication | 2003 |
| Buttershaw Limited | Wholesale & retail | 2013 |
| Button's and Bow's Day Nursery Ltd. | Education | 2015 |
| Buttonwood Engineering Ltd | Professional & scientific | 2026 |
| Buvik Crop Nutrition (Netherlands) Co., Ltd | Mining & quarrying | 2023 |
| Buxton Marketing Ltd | Professional & scientific | 2014 |
| Buy & Go (Holdings) Limited | Real estate | 2024 |
| Buy & Go Cars Ltd | Wholesale & retail | 2015 |
| Buy 4U Ltd | Wholesale & retail | 2018 |
| Buy Advertising Ltd | Professional & scientific | 2022 |
| Buy BOT Ltd | Wholesale & retail | 2020 |
| Buy ME! Vehicle Sales Ltd | Wholesale & retail | 2025 |
| Buy Popular Demand Ltd | Wholesale & retail | 2019 |
| Buy Sell Deliver Limited | Wholesale & retail | 2025 |
| Buyerlane Ltd | Wholesale & retail | 2022 |
| Buyers Bliss Limited | Wholesale & retail | 2025 |
| Buylet Ltd | Wholesale & retail | 2025 |
| Buymeeverywhere Limited | Wholesale & retail | 2022 |
| Buymingle Limited | Wholesale & retail | 2025 |
| Buymucho Limited | Hospitality | 2016 |
| Buymyloves Ltd | Wholesale & retail | 2024 |
| Buynax Limited | Wholesale & retail | 2025 |
| Buyneed Ltd | Wholesale & retail | 2026 |
| Buyonn Ltd | Wholesale & retail | 2026 |
| Buytrix Ltd | Wholesale & retail | 2026 |
| Buyzara PVT Ltd | Wholesale & retail | 2024 |
| Buzit Ltd | Wholesale & retail | 2025 |
| Buzz Automatic Driving Schools Ltd | Administrative & support | 2017 |
| Buzz Business Solutions Ltd | Professional & scientific | 2024 |
| Buzz Buy Cart Limited | Wholesale & retail | 2025 |
| Buzzard Buzzard Buzzard Ltd | Arts & recreation | 2019 |
| Buzzrock Management Solutions Ltd | Real estate | 2019 |
| Buzzstreets Limited | Administrative & support | 2015 |
| BV Construction & Demolition UK Limited | Manufacturing | 2022 |
| Bvanzio Ltd | Wholesale & retail | 2021 |
| Bvbb Glazing Ltd | Construction | 2019 |
| Bvcon Ltd | Wholesale & retail | 2019 |
| BVG Europe Ltd | Administrative & support | 2019 |
| Bviuon Limited | Wholesale & retail | 2021 |
| BVL Catering Repairs Limited | Manufacturing | 2021 |
| BVL Group Ltd | Wholesale & retail | 2025 |
| Bvrsma LLP | | 2010 |
| Bwalya Limited | Wholesale & retail | 2025 |
| Bwbachod CYF | Professional & scientific | 2026 |
| BWC Comps Ltd | Construction | 2026 |
| BWC Trading Limited | Wholesale & retail | 2019 |
| Bwing Global Solutions Ltd | Information & communication | 2025 |
| Bwit Australia PTY Ltd | Wholesale & retail | 2026 |
| BWJ Developments Ltd | Construction | 2024 |
| Bwlb Ltd | Information & communication | 2022 |
| BWM Windows and Doors Ltd | Manufacturing | 2023 |
| BWS Marketing Solutions Limited | Information & communication | 2019 |
| BWT Consulting Ltd | Information & communication | 2016 |
| Bwyd OR Galon Ltd | Hospitality | 2015 |
| BXB ENT Limited | Information & communication | 2017 |
| Bxin Trade Ltd | Wholesale & retail | 2025 |
| BY Kakao Ltd | Wholesale & retail | 2023 |
| BY Kathryn Ellen Ltd | Other services | 2024 |
| BY Lewis Limited | Manufacturing | 2013 |
| BY Nature's Beauty Limited | Other services | 2019 |
| BY Orzan Ltd | Construction | 2024 |
| BY Raisin GmbH Ltd | Construction | 2026 |
| BY the Book Limited | Professional & scientific | 2010 |
| BY V Limited | Wholesale & retail | 2025 |
| BY ZOE Beauty Academy Ltd | Other services | 2025 |
| Byanise Ltd | Professional & scientific | 2013 |
| Byariq Agriculture Ltd | Wholesale & retail | 2025 |
| BYB Accountancy Limited | Professional & scientific | 2003 |
| BYB Big Yellow Boots Ltd | Professional & scientific | 2025 |
| BYB Decoration Material Co., Limited | Manufacturing | 2021 |
| BYB Ltd | Manufacturing | 2016 |
| Byba Properties Ltd | Real estate | 2023 |
| Bybw Limited | Wholesale & retail | 2025 |
| BYC Impex UK Ltd | Wholesale & retail | 2020 |
| Bye-Airport Incorporation Ltd | Wholesale & retail | 2018 |
| Byeway Limited | Hospitality | 2005 |
| Byford Scaffolding Ltd | Construction | 2023 |
| Byjo.Co.Uk Limited | Manufacturing | 2014 |
| BYM Astral Limited | Real estate | 2020 |
| BYM Atrium Limited | Real estate | 2022 |
| BYM Exmouth Limited | Real estate | 2020 |
| BYM Horsham 3 Limited | Real estate | 2021 |
| BYM Horsham Limited | Real estate | 2021 |