| Breathe and BEE Ltd | Wholesale & retail | 2026 |
| Brentford Tyres Limited | Wholesale & retail | 2021 |
| Brick House Builders Ltd | Construction | 2018 |
| Bridgepoint Staffing Ltd | Health & social care | 2026 |
| Bright & Ledgerly Ltd | Professional & scientific | 2026 |
| Bright Minds Academy Limited | Education | 2018 |
| Bright Node Ltd | Information & communication | 2023 |
| Brightsight UK Ltd | Hospitality | 2023 |
| Brill Family Limited | Professional & scientific | 2024 |
| Brilliant BIN Cleaning Ltd | Administrative & support | 2019 |
| Brink's (UK) Limited | Administrative & support | 1990 |
| Brink's Global Services, Ltd. | Transport & logistics | 1999 |
| Brink's Limited | Transport & logistics | 1969 |
| Brit Cyber Solutions Ltd | Information & communication | 2024 |
| Brit Experts Healthcare Ltd | Health & social care | 2019 |
| Britannia Autoexports Ltd | Wholesale & retail | 2024 |
| Britannia Professional Care Ltd | Health & social care | 2024 |
| Britbuy Ltd | Wholesale & retail | 2025 |
| Britfix Motors Ltd | Wholesale & retail | 2026 |
| British International Freight Association | Other services | 1944 |
| Britmandu Limited | Wholesale & retail | 2026 |
| Brits Auto Farm Ltd | Wholesale & retail | 2025 |
| Britsol Education Ltd | Education | 2024 |
| Britzz Limited | Hospitality | 2024 |
| BRM Estates Ltd | Real estate | 2022 |
| Bro's Garage Ltd | Wholesale & retail | 2025 |
| Broadnet Technologies Ltd | Wholesale & retail | 2025 |
| Broadsoft Ltd | Information & communication | 2005 |
| Broadsoft UK Holding Company Ltd | Information & communication | 2012 |
| Broadsoft UK Operating Company Ltd | Information & communication | 2012 |
| Brookshaw Designs Limited | Professional & scientific | 2025 |
| Brothers B Joinery Ltd | Manufacturing | 2022 |
| Brothers PVT Ltd | Wholesale & retail | 2018 |
| Brownie Bliss Co Ltd | Hospitality | 2025 |
| Browns Home Staging Limited | Professional & scientific | 2024 |
| BSD Cars Ltd | Transport & logistics | 2019 |
| BSJ UK Limited | Real estate | 2015 |
| Bsml Construction Limited | Construction | 2023 |
| Bstar Solutions Limited | Information & communication | 2023 |
| BT Logistic Limited | Transport & logistics | 2024 |
| BTF Tamils Forum UK Limited | Other services | 2019 |
| Bubblestown Ltd | Wholesale & retail | 2018 |
| Bubulae Ltd | Hospitality | 2024 |
| BUD Soft Ltd | Information & communication | 2013 |
| Buddha Construction Limited | Construction | 2020 |
| Budget Shop Limited | Wholesale & retail | 2014 |
| Budget Steel and Fencing Ltd | Manufacturing | 2020 |
| Build Acasa Ltd | Construction | 2025 |
| Build UP Builder Limited | Construction | 2020 |
| Buildant Ltd | Construction | 2009 |
| Building Solution 360 Limited | Construction | 2024 |
| Buildovest Ltd | Construction | 2026 |
| Buildsaini Limited | Real estate | 2024 |
| Bulolo and Family Limited | Health & social care | 2012 |
| Burgergo Limited | Hospitality | 2021 |
| Burhan Properties Limited | Real estate | 2023 |
| Business Analytics Consultants Limited | Information & communication | 2014 |
| BUYING2DAY.COM Limited | Wholesale & retail | 2011 |
| Buysold Ltd | Wholesale & retail | 2024 |
| Bwnm Transport Ltd | Transport & logistics | 2019 |
| C & a Building Solutions Limited | Construction | 2013 |
| C & C Alliance Contractors Limited | Administrative & support | 2009 |
| C & R Ceylon UK Ltd | Extraterritorial | 2021 |
| C a Jones 7 Pictures Ltd | Professional & scientific | 2025 |
| C N Motors Limited | Wholesale & retail | 2004 |
| C Plus Line Solution Ltd | Information & communication | 2015 |
| C&A Solutions Private Ltd | Professional & scientific | 2025 |
| C&C 2015 Limited | Transport & logistics | 2017 |
| C&C Thermal Insulation Ltd | Construction | 2026 |
| C.C.Anton Construct Ltd | Construction | 2026 |
| C.D.A. Construct Ltd | Construction | 2026 |
| C0DE4DEV Limited | Information & communication | 2024 |
| C3 Vision Ltd | Health & social care | 2021 |
| CAB N Coach Ltd | Administrative & support | 2019 |
| Cabyy Ltd | Transport & logistics | 2026 |
| Cabzy Holidays Limited | Administrative & support | 2025 |
| CAC Property Consult Ltd | Real estate | 2016 |
| Cade Investment Limited | Real estate | 2026 |
| Caesar Pictures Ltd | Information & communication | 2007 |
| Cafetreatz Feltham Ltd | Hospitality | 2021 |
| Cake Connection Ltd | Wholesale & retail | 2025 |
| Calliber Skills Technology Limited | Wholesale & retail | 2022 |
| Callopa Ltd | Information & communication | 2026 |
| Calton Ltd | Health & social care | 2014 |
| Camelia Beauty Ltd | Other services | 2025 |
| Campozano Brothers Ltd | Transport & logistics | 2025 |
| CAN & Able Ltd | Construction | 2014 |
| Candice Bryan’S Swim School Limited | Arts & recreation | 2024 |
| CANE-82 Transport Ltd | Wholesale & retail | 2018 |
| Cantinho SAO Vicente Ltd | Hospitality | 2015 |
| Cape Aston Properties Limited | Real estate | 2018 |
| Capital & KIN Collective Ltd | Real estate | 2025 |
| Capital Cable Jointing Ltd | Construction | 2017 |
| Capital H Catering & Leisure Equipment Ltd | Hospitality | 2002 |
| Capital Management and Investments Limited | Real estate | 2023 |
| Capitolia Automotive Ltd | Extraterritorial | 2016 |
| Capri Commerce Ltd | Wholesale & retail | 2021 |
| Captivate Properties Ltd | Construction | 2020 |
| Car Saaz Ltd | Wholesale & retail | 2025 |
| Car Sense Solutions Ltd | Information & communication | 2025 |