| Bockatech Ltd | Professional & scientific | 2015 |
| Bofi Racing Ltd | Manufacturing | 2016 |
| Bolting Developments Limited | Real estate | 1998 |
| Bona Sort Ltd | Wholesale & retail | 2025 |
| Bond and Moulds Limited | Manufacturing | 2008 |
| Bond Developers Ltd | Real estate | 2022 |
| Bond Health Ltd | Health & social care | 2021 |
| Bondar Labs Ltd | Manufacturing | 2026 |
| Bonded Components Limited | Manufacturing | 1984 |
| Bonnett's (Bakers) Limited | Real estate | 1979 |
| Bonnetts Gate Residents Association (Leasehold) Limited | Households | 2019 |
| Bonska Consultancy Ltd | Professional & scientific | 2019 |
| Bood Health Ltd | Health & social care | 2023 |
| Bood Investments Ltd | Financial services | 2024 |
| Boomerang Radio Limited | Information & communication | 2025 |
| Boomtown Boys Ltd | Wholesale & retail | 2025 |
| Booth Concrete Limited | Wholesale & retail | 1959 |
| Booz Allen Commercial Cyber (UK), Ltd. | Professional & scientific | 2021 |
| Booz Allen Hamilton International (U.K.) Ltd | Professional & scientific | 2000 |
| Borney UK Limited | Wholesale & retail | 1993 |
| Boss Wiring Ltd | Manufacturing | 2019 |
| Boudwells Limited | Real estate | 2024 |
| Bouncy Castle Hire Limited | Administrative & support | 2017 |
| Bowens Amalgamated Services Limited | Real estate | 2017 |
| Boxworth 52 Limited | Agriculture & fishing | 2024 |
| Boxworth Limited | Wholesale & retail | 2017 |
| Boyzmedic Ltd | Health & social care | 2016 |
| Bracey Properties Ltd | Real estate | 2025 |
| Bracken Asset Management Limited | Real estate | 2024 |
| Bracken Properties Limited | Real estate | 2010 |
| Bradbrook Physiotherapy Ltd | Health & social care | 2008 |
| Bradgate Grounds Maintenance Limited | Administrative & support | 2020 |
| Bradley Structures Ltd | Professional & scientific | 2023 |
| Brampton Cleaners Ltd | Administrative & support | 2025 |
| Brampton Energy Storage Limited | Construction | 2021 |
| Brampton Hair Company Limited | Other services | 2020 |
| Brampton Medics Ltd | Health & social care | 2026 |
| Brampton Motor Group Ltd | Wholesale & retail | 2025 |
| Brampton Park Ltd | Construction | 2014 |
| Brand Commercial Property Limited | Real estate | 1998 |
| Brand Communications Limited | Manufacturing | 1991 |
| Brand Elevation Limited | Extraterritorial | 2005 |
| Brand Motorsports Limited | Arts & recreation | 1998 |
| Brand New Old School Ltd | Professional & scientific | 2008 |
| Brand Planet Ltd | Administrative & support | 2011 |
| Brand Plumbing Ltd | Construction | 2022 |
| Branding Eaze Ltd | Wholesale & retail | 2025 |
| Brands in Bloom Ltd | Wholesale & retail | 2021 |
| Brass Building Freehold Limited | Households | 2013 |
| Brass Building RTM Company Limited | Households | 2012 |
| Brench Plumbing Services Limited | Construction | 2016 |
| Breve Technology Holdings Limited | Financial services | 2020 |
| Brick Game Limited | Wholesale & retail | 2006 |
| Bridge Planning Ltd | Professional & scientific | 2022 |
| Bright Circle Learning Community Interest Company | Education | 2023 |
| Bright Mortgage Advice Limited | Financial services | 2003 |
| Bright Multimedia Ltd | Information & communication | 2001 |
| Bright Silence Limited | Information & communication | 2015 |
| Bright Wealth Management Limited | Financial services | 2011 |
| Brightfeather Ltd | Administrative & support | 2014 |
| Brimstone Energy Limited | Construction | 2023 |
| Brindlebay Limited | Agriculture & fishing | 2022 |
| Brington North LLP | | 2016 |
| Briony Rice Associates Ltd | Professional & scientific | 2023 |
| Bristows Cycles Limited | Wholesale & retail | 2018 |
| Britannia Garage Service Ltd | Wholesale & retail | 2025 |
| Britannia Homecare Solutions Ltd | Administrative & support | 2021 |
| British Isles Grooming Association Ltd | Other services | 2016 |
| Britt Classic Cars Ltd | Administrative & support | 2019 |
| Britt Property Ltd | Real estate | 2014 |
| Broadland Toilet Hire Ltd | Water & waste | 2021 |
| Broadley Automotive Limited | Wholesale & retail | 2013 |
| Brody House Management Limited | Households | 2004 |
| Bromax UK Logistics Ltd | Transport & logistics | 2021 |
| Brook Farm (Cambs) Ltd | Administrative & support | 2013 |
| Brook Martin Associates Ltd | Professional & scientific | 2015 |
| Brookside Financial Consulting Services Ltd | Financial services | 2013 |
| Brookview Glaziers Ltd | Construction | 2010 |
| Brothers Construction Essex Limited | Construction | 2019 |
| Brothers Construction Suffolk Limited | Construction | 2021 |
| Broughton Consultancy Limited | Administrative & support | 2017 |
| BROW4 CIC | Health & social care | 2021 |
| Brown Hare Limited | Real estate | 2023 |
| Browns Fencing & Landscapes Limited | Administrative & support | 2023 |
| Bruce & Walker Limited | Manufacturing | 1959 |
| BS Graves Electrical Limited | Construction | 2002 |
| BSP Technologies Limited | Information & communication | 2010 |
| Bsps Area 11 Limited | Arts & recreation | 2007 |
| Bsps Area 12 Limited | Arts & recreation | 2007 |
| Bsps Area 13A Limited | Arts & recreation | 2007 |
| Bsps Area 13B Limited | Arts & recreation | 2007 |
| Bsps Area 14 Limited | Arts & recreation | 2007 |
| Bsps Area 15 Limited | Arts & recreation | 2007 |
| Bsps Area 15A Limited | Arts & recreation | 2007 |
| Bsps Area 16 Limited | Arts & recreation | 2007 |
| Bsps Area 17 Limited | Arts & recreation | 2007 |
| Bsps Area 1A Limited | Arts & recreation | 2007 |
| Bsps Area 1B Limited | Arts & recreation | 2007 |
| Bsps Area 2A Limited | Arts & recreation | 2007 |
| Bsps Area 2B Limited | Arts & recreation | 2007 |