| Boxley Tyre Services Limited | Wholesale & retail | 1969 |
| Boyds Electrical Ltd | Construction | 2011 |
| Boykov 04 Ltd | Transport & logistics | 2018 |
| BP Elite Services Ltd | Administrative & support | 2024 |
| Bpcg Limited | Professional & scientific | 2013 |
| BPMC26 Ltd | Construction | 2025 |
| Brackenbury Lodge Residents Association Limited | Households | 1997 |
| Brad's Tyres Ltd | Wholesale & retail | 2023 |
| Bradley & Co Limited | Professional & scientific | 2011 |
| Bradley Jack Designs Ltd | Professional & scientific | 2023 |
| Braeburn Holdings Ltd | Real estate | 2024 |
| Braided UK Limited | Other services | 2025 |
| Braincup Media Ltd | Information & communication | 2021 |
| Brake Manning Ltd | Financial services | 2026 |
| Bramble Fields Management Company Ltd | Households | 2025 |
| Brand Labs Group Ltd | Financial services | 2024 |
| Brand New Audio Ltd | Information & communication | 2020 |
| Brand New Notebook Ltd | Professional & scientific | 2020 |
| Branded Biscuit Ltd | Manufacturing | 2025 |
| Brandfunk Ltd | Extraterritorial | 2022 |
| Brandsensory Limited | Professional & scientific | 2023 |
| Branta Fields RTM Limited | Administrative & support | 2011 |
| BRB Trucking Limited | Transport & logistics | 2025 |
| Breese Design Limited | Professional & scientific | 2025 |
| Brenna Properties Ltd | Real estate | 2018 |
| Brent Homes Ltd | Real estate | 2023 |
| Brewtech Fabrications Ltd | Manufacturing | 2014 |
| Brickstocks Holdings Limited | Real estate | 2019 |
| Bridge Housing and Support Ltd | Real estate | 2025 |
| Bridge Transits Ltd | Wholesale & retail | 2026 |
| Bridgefield Accounting & Projects Ltd | Professional & scientific | 2026 |
| Bridgeman Restoration Ltd | Construction | 2023 |
| Bridgers Craft Limited | Manufacturing | 2025 |
| Bridgewood Rochester Limited | Real estate | 2002 |
| Bright & Breezyy Cleaning Solutions Ltd | Administrative & support | 2025 |
| Bright Paths Learning & Technology Foundation CIC | Education | 2025 |
| Bright Scaffolding Ltd | Construction | 2025 |
| Bright Sparks Education Service Ltd | Education | 2024 |
| Brightcad Ltd | Professional & scientific | 2025 |
| Brighter Future Organisation Ltd | Education | 2023 |
| Brighton Pest Control Limited | Professional & scientific | 2024 |
| Brightside Heating Services Limited | Construction | 2016 |
| Brightside Properties Limited | Real estate | 2002 |
| Brightside Services Holdings Limited | Financial services | 2013 |
| Brightwey Beauty Ltd | Other services | 2024 |
| Brightwey Ltd | Construction | 2023 |
| Brightwey Removals Ltd | Transport & logistics | 2025 |
| Brimsted Auto Repairs Ltd | Wholesale & retail | 2025 |
| Bring Something Back Ltd | Information & communication | 2022 |
| Brit Enterprise Limited | Construction | 2013 |
| Britsmind AI Ltd | Education | 2026 |
| Britten Kinslow Investments Ltd | Real estate | 2023 |
| Britvape Ltd | Wholesale & retail | 2021 |
| Broadway Car Wash Ltd | Administrative & support | 2025 |
| Broc Group Limited | Administrative & support | 2018 |
| Brogdale Butchers Ltd | Wholesale & retail | 2012 |
| Brompton Farm Road Residents Limited | Households | 1973 |
| Brompton Motor Company (Canterbury) Limited | Transport & logistics | 1975 |
| Brompton Motor Company Limited | Transport & logistics | 1965 |
| Brook Blast Limited | Construction | 2022 |
| Brookside Court (HOO) Limited | Households | 1984 |
| Brosnan Technology Consulting Ltd | Information & communication | 2026 |
| Brother Grill Ltd | Hospitality | 2024 |
| Brothers Cafe Strood Ltd | Hospitality | 2021 |
| Brown COW Audio Visual Ltd | Information & communication | 2014 |
| Bruno Construction.Co.Uk Ltd | Construction | 2026 |
| Bryant and Daughters Bookkeeping Services Limited | Professional & scientific | 2018 |
| BSC & SON Limited | Administrative & support | 2004 |
| BSC & SON Secretaries Limited | Extraterritorial | 2008 |
| BSJ Estate Management Limited | Real estate | 2024 |
| BSJ Healthcare Professionals Limited | Health & social care | 2015 |
| Bssted Limited | Health & social care | 2024 |
| Bstr-Studio Ltd | Information & communication | 2025 |
| BT Property Investments Ltd | Real estate | 2021 |
| BTM Coins and Media Limited | Wholesale & retail | 2021 |
| BTP First Limited | Financial services | 2019 |
| Bubble & Scruff Limited | Education | 2015 |
| Buckstar Property Management Ltd | Real estate | 2025 |
| Build an Event Limited | Information & communication | 2014 |
| Build-Uk Limited | Construction | 2013 |
| Buildforce CM Ltd | Construction | 2019 |
| Building Compliance Services Ltd | Professional & scientific | 2016 |
| Buildscape Supplies Limited | Wholesale & retail | 2015 |
| Built to Perfection Ltd | Construction | 2024 |
| Bullvin Electrical Limited | Construction | 2012 |
| Buluk BIZ Ltd | Financial services | 2026 |
| Bunny Run Childcare Limited | Education | 2002 |
| Burch Services Ltd | Construction | 2026 |
| Burham Community Pride Ltd | Hospitality | 2023 |
| Burlanes Site Services Limited | Construction | 2014 |
| Burney Street London Management Company Limited | Real estate | 2016 |
| Bush Developments Ltd | Real estate | 2021 |
| BUSINESSCOUT24 Ltd | Manufacturing | 2026 |
| Businology Limited | Information & communication | 2012 |
| Bussybamy.A.J Ltd | Health & social care | 2013 |
| Butcher of Brogdale Ltd | Wholesale & retail | 2008 |
| Butterbridge Limited | Real estate | 2024 |
| Buyadigger Limited | Extraterritorial | 2014 |
| Buyblend Ltd | Wholesale & retail | 2025 |
| Buzi Limited | Transport & logistics | 2025 |