| Bissett-Powell Ltd | Administrative & support | 2025 |
| Bitclaritymediaholdings Ltd | Information & communication | 2025 |
| Bizagi Limited | Information & communication | 2005 |
| Bizbritain Limited | Professional & scientific | 2023 |
| Black Cat Ltd | Wholesale & retail | 2024 |
| Blackrock Pharmaceuticals Limited | Manufacturing | 2007 |
| Blandstone Limited | Other services | 1984 |
| Blaser Mills LLP | | 2014 |
| Blaser Mills Trust Corporation Limited | Professional & scientific | 2026 |
| Blind Inspiration Marlow Limited | Wholesale & retail | 2024 |
| Blind Swan Limited | Arts & recreation | 2023 |
| Bloom Garden Services Limited | Administrative & support | 2018 |
| Bloom Tree Care Limited | Administrative & support | 2022 |
| Blossom Prime Development Limited | Real estate | 2019 |
| Bloxbid Ltd | Wholesale & retail | 2025 |
| Bloxstop Ltd | Wholesale & retail | 2025 |
| Blue Castle Digital Limited | Professional & scientific | 2024 |
| Blue Chip Security Limited | Administrative & support | 1997 |
| Blue Day Healthcare Limited | Professional & scientific | 2023 |
| Blue Inicio Ltd | Information & communication | 2024 |
| Blue Moray Limited | Professional & scientific | 2021 |
| Blue Planet Recordings Limited | Wholesale & retail | 1996 |
| Blue RAY Building Solutions Ltd | Construction | 2025 |
| Blue Sky Container Investments Ltd | Administrative & support | 2021 |
| Blue Sky Intermodal (UK) Ltd. | Wholesale & retail | 2002 |
| Blue Space Property Group Limited | Professional & scientific | 2003 |
| Blue Stack Plant Ltd | Professional & scientific | 2023 |
| Blue Tiger Property Limited | Real estate | 2020 |
| Blue Tiger Solutions Limited | Information & communication | 2007 |
| BM Data Services Limited | Professional & scientific | 2018 |
| BNT Europe Limited | Financial services | 2010 |
| Bone Soup Productions Ltd | Information & communication | 2016 |
| Booker Aviation Limited | Transport & logistics | 2018 |
| Booker Gliding Club Limited | Arts & recreation | 1980 |
| Bordeaux UK Holdings I Limited | Financial services | 2017 |
| Bordeaux UK Holdings II Limited | Financial services | 2017 |
| Bordeaux UK Holdings III Limited | Financial services | 2017 |
| Bosinney Consulting Ltd | Information & communication | 2022 |
| Boston Capital Finance Ltd | Financial services | 2023 |
| Boston Capital Partners Limited | Construction | 2025 |
| Boundless CFO Partners Ltd | Professional & scientific | 2026 |
| Bourne Towers Limited | Real estate | 2024 |
| Boveney (Slough) Management Company Limited | Households | 1984 |
| Bovingdon Holdings Limited | Financial services | 2021 |
| Box Smart Ltd | Professional & scientific | 2025 |
| Boyn Hill Residents (Maidenhead) Limited | Households | 1973 |
| Bradshaw QA Consultancy Limited | Professional & scientific | 2016 |
| Brainstorm Health Solutions Limited | Health & social care | 2016 |
| Brambledene Visual Effects Ltd | Administrative & support | 2011 |
| Bramley Gardens Residents Management Company Limited | Households | 2013 |
| Bramley Lodge Residences Ltd | Real estate | 2025 |
| Brand Spark 360 Ltd | Information & communication | 2023 |
| Brandfibian Ltd | Professional & scientific | 2026 |
| Brandon James Limited | Administrative & support | 2014 |
| Brandon James Partners LLP | | 2021 |
| Branova Labs Limited | Information & communication | 2025 |
| Bravo Post Production Limited | Information & communication | 1998 |
| Brayscape Ltd | Administrative & support | 2024 |
| Breckenridge Technologies Limited | Other services | 2009 |
| Bridge Technical Consultants Limited | Administrative & support | 2012 |
| Bridge Wireless Solutions Limited | Administrative & support | 2017 |
| Briggs Books Limited | Arts & recreation | 2005 |
| Bright Yellow Beauty Ltd | Other services | 2023 |
| Brighter Futures Together C.I.C. | Health & social care | 2022 |
| Brighter Projects Ltd | Professional & scientific | 2022 |
| Brimble Tech Ltd | Energy | 2019 |
| Bristol Court Freehold Limited | Households | 2010 |
| Bristol Novelty Limited | Wholesale & retail | 1983 |
| British Menopause Society | Health & social care | 1992 |
| Broadlands Court RTM Company Limited | Households | 2014 |
| Brokerco Limited | Financial services | 2021 |
| Browns Court (Cippenham) Management Company Limited | Households | 1999 |
| Bruce Close RTM Company Limited | Households | 2006 |
| BTL Family Company Limited | Financial services | 2011 |
| Bubble Butler & Co. Ltd | Other services | 2025 |
| Buckingham Court Leaseholders Association Limited | Households | 1995 |
| Bucks Car Hire Limited | Administrative & support | 2003 |
| BUD and Belle Ltd | Professional & scientific | 2024 |
| Buildcharm Property Management Limited | Extraterritorial | 2000 |
| Bunhill Limited | Professional & scientific | 2017 |
| Buox Ltd | Construction | 2023 |
| Burlington Engineers Limited | Manufacturing | 2006 |
| Business Fit International Ltd | Professional & scientific | 2018 |
| Business Rates Consultancy Ltd | Professional & scientific | 2018 |
| Butlers Chocolate Cafe (London) Limited | Hospitality | 2007 |
| Butlers Court (High Wycombe) Residents Company Limited | Households | 1987 |
| Buttimer Holdings Limited | Real estate | 2022 |
| BWP Group Limited | Professional & scientific | 2007 |
| BWP Holdings Limited | Financial services | 2016 |
| BWP Topco Limited | Financial services | 2024 |
| BY Design Interiors Ltd | Professional & scientific | 2025 |
| C & G Contractors Limited | Construction | 2005 |
| C Crabtree Consulting Limited | Information & communication | 2013 |
| C Stark Music Limited | Information & communication | 2012 |
| C&N Management Ltd | Professional & scientific | 2010 |
| Cadd Biotech Ltd | Professional & scientific | 2026 |
| Cadden Pharma Services Limited | Professional & scientific | 2023 |
| Cadence Search Limited | Administrative & support | 2024 |
| Caerus WEB3 Limited | Information & communication | 2022 |
| Cake House High Wycombe Ltd | Wholesale & retail | 2021 |