| Beards Holding Company Limited | Financial services | 2023 |
| Beautypro Ltd | Manufacturing | 2010 |
| Beckwith Leisure Services Ltd | Arts & recreation | 2025 |
| Beckwith Property Services Limited | Real estate | 2010 |
| Beechtime Limited | Extraterritorial | 1998 |
| Beeney & Co Limited | Construction | 1987 |
| Belfortandbellhousing Ltd | Real estate | 2026 |
| Bell Walk DRY Cleaners Ltd | Other services | 2015 |
| Belle & Wilde Limited | Manufacturing | 2019 |
| Benross Solutions Limited | Information & communication | 2015 |
| Bersche-Rolt a Ltd | Construction | 2020 |
| Bersche-Rolt B Ltd | Construction | 2020 |
| Bersche-Rolt Group Ltd | Construction | 2020 |
| Bersche-Rolt Limited | Manufacturing | 1992 |
| Bersche-Rolt LPS Ltd | Construction | 2020 |
| Best Ironwork Limited | Manufacturing | 1997 |
| BET Ahoy Ltd | Arts & recreation | 2025 |
| BET TOM Ltd | Arts & recreation | 2023 |
| Bevintagegb Ltd | Extraterritorial | 2021 |
| Bexhill Seaside Holdings Ltd | Households | 2020 |
| BF Futura (UK) Ltd. | Professional & scientific | 2014 |
| BF Line Holding Limited | Financial services | 2022 |
| BHC Logistics Limited | Transport & logistics | 2005 |
| Bidshop Ltd | Wholesale & retail | 2019 |
| Big High Limited | Real estate | 2020 |
| Billbarter UK Ltd. | Real estate | 2015 |
| Binary Testing Limited | Professional & scientific | 2002 |
| Birchgrove Homes Limited | Construction | 1995 |
| Birchwood Tree and Estate Management Ltd | Administrative & support | 2018 |
| BIT of K Ltd | Professional & scientific | 2013 |
| Bitrab Ltd | Information & communication | 2013 |
| Black Crest Construction Limited | Professional & scientific | 2025 |
| Black ROK Design Limited | Wholesale & retail | 2011 |
| Blackboys Service Station Limited(The) | Wholesale & retail | 1947 |
| Blackness Lane Limited | Information & communication | 2016 |
| Blake's Joinery Ltd. | Construction | 2012 |
| Blakestone Limited | Real estate | 2001 |
| Blddb Ltd | Real estate | 2019 |
| BLH Properties Ltd | Financial services | 2015 |
| BLOCK4 Recorder Quartet Limited | Wholesale & retail | 2021 |
| Bloomsbury Innovation Group Community Interest Company | Extraterritorial | 2016 |
| Bloxx Limited | Construction | 2024 |
| Bluebell Railway Preservation Society | Arts & recreation | 2021 |
| Bluerose Estates Ltd | Real estate | 2020 |
| BML2 Consultancy Limited | Professional & scientific | 2016 |
| BOB Wheeler Photography Ltd | Professional & scientific | 2013 |
| Bomas Dentlab Ltd | Manufacturing | 2017 |
| Bookworm Online Services Ltd. | Administrative & support | 2014 |
| Borgbit Ltd | Information & communication | 2024 |
| Born Again Plastics Recycling Ltd | Water & waste | 2006 |
| Boswell Associates (Architecture) Limited | Professional & scientific | 2002 |
| Boucle LLP | | 2021 |
| Boughton MEP Limited | Professional & scientific | 2026 |
| Bouji MF Ltd | Extraterritorial | 2025 |
| Brahman Ltd | Health & social care | 2019 |
| Bramble Brews Ltd | Manufacturing | 2020 |
| Bridges and Hearts Publishing Ltd | Wholesale & retail | 2022 |
| Bridgeway Exports Ltd | Wholesale & retail | 2026 |
| Brightapp Ltd | Information & communication | 2015 |
| Brightdog Theatre Ltd | Arts & recreation | 2025 |
| Brighterbikes Limited | Wholesale & retail | 2013 |
| Brighton Bioworks Limited | Professional & scientific | 2025 |
| Brincliffe Management Company Limited | Professional & scientific | 1986 |
| Britannic Bifold Company Limited | Construction | 2016 |
| British Divers Marine Life Rescue | Professional & scientific | 1990 |
| British Steel Frame Company Limited(The) | Real estate | 1935 |
| Broad Innovations Limited | Information & communication | 2015 |
| Bromley Craft Products Limited | Wholesale & retail | 2008 |
| Brook House Residents Association Limited | Real estate | 2005 |
| Brooker Flooring Ltd | Construction | 2025 |
| BRT Heritage Assets Ltd | Other services | 2025 |
| BRT Trustee Limited | Administrative & support | 2017 |
| Brudenell Limited | Professional & scientific | 2026 |
| Bruton Brickwork Ltd | Construction | 2021 |
| BS Network Marketing Ltd | Information & communication | 2015 |
| Bs-Pro Consulting Ltd | Information & communication | 2011 |
| BSF1 Limited | Financial services | 2024 |
| Bstock Worldwide Limited | Wholesale & retail | 2019 |
| Bsuk Ltd | Information & communication | 2016 |
| BTS Chicking Ltd | Hospitality | 2024 |
| Buckham Hill Investments Ltd | Administrative & support | 2024 |
| Bush Consultants Ltd | Professional & scientific | 2017 |
| Buxted Autos Ltd | Wholesale & retail | 2023 |
| Buxted Bike Workshop Ltd | Manufacturing | 2022 |
| Buy UK Products Limited | Extraterritorial | 2020 |
| BVE Consulting Ltd | Professional & scientific | 2021 |
| Bytes Technology Recruitment Ltd | Information & communication | 2018 |
| C & L Farmer Associates LLP | | 2009 |
| C M R Electrical Limited | Energy | 2003 |
| C P Anaesthesia Limited | Health & social care | 2004 |
| C.J. Gowing and SON Limited | Construction | 1993 |
| C.Wilce Tree Surgeons and Landscapers Ltd | Professional & scientific | 2020 |
| CA Payroll Solutions Limited | Professional & scientific | 2012 |
| Caburn Communications Limited | Other services | 2018 |
| Cad-R Tech Ltd | Professional & scientific | 2017 |
| Cadhq Ltd | Administrative & support | 2017 |
| Cafe 212 Ltd | Hospitality | 2018 |
| Calf & Co Limited | Administrative & support | 2014 |
| Callice Limited | Real estate | 2015 |
| Calpin AI Ltd | Information & communication | 2026 |