| Bhunnys Catering Ltd | Hospitality | 2024 |
| BIB 2024 Ltd | Other services | 2024 |
| Big Hand People Limited | Arts & recreation | 1999 |
| Big Orange Software Limited | Professional & scientific | 2007 |
| Bigdatascientists Ltd | Information & communication | 2014 |
| Bilal & Saeedi Limited | Information & communication | 2017 |
| Bilberry Accountants Ltd | Professional & scientific | 2019 |
| Billington Export Limited | Wholesale & retail | 1992 |
| Binns Rail Consulting Limited | Professional & scientific | 2021 |
| Birchlane Limited | Information & communication | 2007 |
| Bishboshbash Ltd | Administrative & support | 2002 |
| Bison Strength and Fitness Limited | Arts & recreation | 2019 |
| Bittell Associates Limited | Professional & scientific | 2009 |
| BJI Consulting Limited | Professional & scientific | 2007 |
| BL Architectural Design Limited | Professional & scientific | 2015 |
| Black Forest Estates Ltd | Information & communication | 2024 |
| Black Horse Developments Limited | Construction | 2016 |
| Black Horse Investments Limited | Construction | 2014 |
| Blackborough Holdings Ltd | Financial services | 2026 |
| Blackthorn Business Media Limited | Information & communication | 2025 |
| Blackthorn Developments Limited | Construction | 2024 |
| Blademedry Limited | Real estate | 2012 |
| Blake's Butchers Ltd | Wholesale & retail | 2026 |
| Blanc Bloc Limited | Wholesale & retail | 2024 |
| Blends for Friends Limited | Manufacturing | 2005 |
| Bloomore (London) Limited | Administrative & support | 2021 |
| Bloomore Limited | Administrative & support | 2021 |
| Blssb Limited | Wholesale & retail | 2023 |
| Blue Compass Ltd | Professional & scientific | 2018 |
| Blue Compass Recruitment Ltd | Administrative & support | 2022 |
| Blue Rock Applications Ltd | Information & communication | 2023 |
| Blue Sky Serviced Apartments Ltd | Hospitality | 2018 |
| BLUE2 Property Services Limited | Real estate | 2019 |
| Bluebridge International Consulting Limited | Professional & scientific | 2011 |
| Blueco Roofing Ltd | Construction | 2026 |
| Blueprint Trust | Information & communication | 2014 |
| Blundell&Co Limited | Hospitality | 2025 |
| BM Grab Hire Limited | Administrative & support | 2023 |
| Bodies in Design Limited | Arts & recreation | 2014 |
| BOE Publishing Ltd. | Information & communication | 1991 |
| Boffin Recruitment Limited | Administrative & support | 2015 |
| Bolly Ltd | Manufacturing | 2023 |
| Boltholes Florida Limited | Other services | 2017 |
| Bonnie X UK Ltd | Information & communication | 2025 |
| Book Systems International Limited | Administrative & support | 2002 |
| Bookaschool Ltd | Wholesale & retail | 2023 |
| Boot and Ball Ltd | Wholesale & retail | 2020 |
| Born&Brand Ltd | Professional & scientific | 2019 |
| Box Elder Ltd | Professional & scientific | 2023 |
| Box Media Design Limited | Professional & scientific | 2021 |
| Boxhill Carpentry Limited | Administrative & support | 2020 |
| Boxhill Partnership Limited | Construction | 2013 |
| BP Partnership Limited | Professional & scientific | 2006 |
| BPY Ltd | Other services | 2019 |
| Brackenfell Property Limited | Real estate | 2021 |
| Bradley Dyer Limited | Professional & scientific | 1997 |
| Bradley Dyer Marketing Limited | Professional & scientific | 1997 |
| Bradley Dyer RAW Limited | Professional & scientific | 2017 |
| Bradmore Way Development Ltd | Construction | 2022 |
| Braeburn (Welford) Management Company Limited | Households | 2025 |
| Braewood Management Limited | Households | 1973 |
| Brain Reframe Ltd | Health & social care | 2016 |
| Brainsells Consulting Limited | Professional & scientific | 2020 |
| Brancaster Health Limited | Financial services | 2022 |
| Brand Hub Studio Ltd | Information & communication | 2022 |
| Brandammo Limited | Administrative & support | 2017 |
| Branks Development Limited | Professional & scientific | 2014 |
| Brann Consulting Limited | Professional & scientific | 2006 |
| Brass Vector Research Ltd | Professional & scientific | 2026 |
| Bremal Consulting Limited | Professional & scientific | 2016 |
| Brent Walsh Limited | Other services | 2005 |
| Brett Wormley Logistics Limited | Other services | 2019 |
| Brey Executive Travel Ltd | Transport & logistics | 2025 |
| Briar Mechanical Services Southern Ltd | Construction | 2021 |
| Brick Stickers Limited | Construction | 2026 |
| Bridge Capital Partners Ltd | Financial services | 2020 |
| Bridge Hall (Burgess Hill) Management Co Ltd | Households | 2022 |
| Bridgepoint Intelligence Ltd | Information & communication | 2025 |
| Brierley Groundworks Services Ltd | Administrative & support | 2007 |
| Brierley-Davies Ltd | Health & social care | 2020 |
| Brightfull Trading Ltd | Administrative & support | 2013 |
| Brightside Digital Limited | Information & communication | 2007 |
| Brilliant Properties Limited | Households | 1998 |
| Brilliu.App Ltd | Information & communication | 2023 |
| Bristow Brickwork & Construction Ltd | Construction | 2023 |
| Britannic Overseas Trading Company Limited | Hospitality | 1998 |
| Brittleware Limited | Construction | 2023 |
| Broadbean.Consultancy Limited | Information & communication | 2018 |
| Brogelles Limited | Extraterritorial | 2014 |
| Brokes Lodge Estate Gardens Investment Limited | Financial services | 2021 |
| Brokes Lodge Estate Gardens,Limited | Households | 1955 |
| Brokes Road Limited | Households | 1998 |
| Brompton Close Reigate (Management) Ltd | Real estate | 2021 |
| Bromsgrove Limited | Real estate | 2014 |
| Bronze Vase Limited | Financial services | 2016 |
| Brook Construction Limited | | 1986 |
| Brook Resources UK Limited | Real estate | 2019 |
| Brook Studio Ltd | Professional & scientific | 2023 |
| Brookdale Limited | Professional & scientific | 2003 |
| Brookridge Partners Limited | Information & communication | 2022 |