| Brow Goals Brighton Ltd | Other services | 2018 |
| Brown Bear Audio Limited | Information & communication | 2023 |
| Brown Ramsey Catering Ltd | Hospitality | 2025 |
| Brownbook Limited | Information & communication | 2008 |
| Brownie Points Shoreham-By-Sea Ltd | Wholesale & retail | 2021 |
| Browns Farm Cottages Management Limited | Households | 2023 |
| Browns Recruitment Consultancy Ltd | Administrative & support | 2023 |
| BRS Maintenance & Decor Ltd | Construction | 2022 |
| BRT Homes Ltd | Real estate | 2022 |
| BRT Stay Limited | Households | 2018 |
| BRUCE2 Ltd | Real estate | 2023 |
| Brulafu Visual Communication Ltd | Other services | 2014 |
| Brunswick Chase Group Ltd | Professional & scientific | 2017 |
| Brunswick Fine Wines and Spirits Limited | Wholesale & retail | 2016 |
| Brunswick Place (ASL) Limited | Real estate | 2022 |
| Brunswick RTM Company Limited | Households | 2017 |
| Brush Brighton Ltd | Arts & recreation | 2022 |
| Brush IT OUT Ltd | Other services | 2024 |
| Bryant Lettings Limited | Real estate | 2020 |
| Bryantwood Photography Limited | Professional & scientific | 2015 |
| Bryterlater Design Limited | Information & communication | 2005 |
| Bspoke Coatings Limited | Construction | 2018 |
| Bsrc Property Solutions Ltd | Households | 2020 |
| BST Transport Limited | Transport & logistics | 2021 |
| BSU Enterprise Limited | Professional & scientific | 2014 |
| BT Brighton Ltd | Hospitality | 2021 |
| BT Pattenden Holdings Limited | Financial services | 2024 |
| BTC Racing Limited | Extraterritorial | 2021 |
| BTF Holdings Ltd | Financial services | 2017 |
| BTF Trustees Limited | Other services | 2025 |
| BTM Community Ltd | Education | 2024 |
| BTM Sports Ltd | Administrative & support | 2015 |
| BTN Marina Car Wash Company 2018 Limited | Wholesale & retail | 2018 |
| BTN Taxi Ltd | Transport & logistics | 2024 |
| BTN Trading Ltd | Wholesale & retail | 2020 |
| Btonbiz Ltd | Financial services | 2022 |
| Btown Flooring Limited | Construction | 2015 |
| Btrm Limited | Professional & scientific | 2015 |
| BTW Consultants Ltd | Information & communication | 2025 |
| Bubba Food Service Ltd | Hospitality | 2025 |
| Bubble Creative Consultancy Limited | Information & communication | 2015 |
| Bubble Fish Consultancy Ltd | Administrative & support | 2015 |
| Bubble POP (Brighton) Ltd | Wholesale & retail | 2025 |
| Bubblelife Ltd | Manufacturing | 2019 |
| Bubbles and Balls Ltd | Wholesale & retail | 2020 |
| Bubbles Franchise Limited | Hospitality | 2023 |
| Buckingham Close (Brighton) Limited | Households | 2008 |
| Buckingham Place RTM Company Limited | Households | 2013 |
| Buckmaster & Sons Property Management Ltd | Real estate | 2009 |
| Buddyng Limited | Administrative & support | 2019 |
| Buddy’S Caff Ltd | Hospitality | 2025 |
| Buff Motion Limited | Information & communication | 2014 |
| Buffalo American Bar & Grill Limited | Hospitality | 2012 |
| Buffalo Construction Limited | Construction | 2019 |
| Buffet Ltd | Hospitality | 2023 |
| BUG Animations Limited | Information & communication | 2009 |
| Build Big Ltd | Information & communication | 2010 |
| Build Green Construction Ltd | Construction | 2026 |
| Build Safe Homes Ltd | Construction | 2024 |
| Buildability Works Limited | Construction | 2020 |
| Buildaxis Ltd | Professional & scientific | 2023 |
| Buildbrighton | Other services | 2010 |
| Building Community Innovation Ltd | Professional & scientific | 2026 |
| Building Human Resources Ltd | Administrative & support | 2006 |
| Building Systems (Distribution) Holdings Ltd | Extraterritorial | 2013 |
| Building Systems (Distribution) Ltd | Administrative & support | 2009 |
| Buildmatt Limited | Construction | 2020 |
| Buildsync Ltd | Information & communication | 2020 |
| Built by Buffalo Ltd | Information & communication | 2007 |
| Built Different Media Limited | Information & communication | 2022 |
| Built Services Design Associates Limited | Professional & scientific | 2011 |
| Bula Properties Limited | Real estate | 2007 |
| Bulk Bites Ltd | Wholesale & retail | 2025 |
| Bulk OIL Containers Limited | Manufacturing | 1901 |
| Bulldog Film Distribution Limited | Information & communication | 2010 |
| Bulldog Tavern Ltd | Hospitality | 2024 |
| Bulldogs Digital Ltd | Professional & scientific | 2022 |
| Bullhousen Holdings Limited | Real estate | 2026 |
| Bullstein Holdings Limited | Real estate | 2020 |
| Bulsatcom UK Holdco Limited | Financial services | 2019 |
| Bumble Tents & Events Limited | Hospitality | 2017 |
| BUN and Bean Ltd | Hospitality | 2016 |
| Bungaroosh Brighton Limited | Wholesale & retail | 2017 |
| Bunks and Box Ltd | Wholesale & retail | 2025 |
| Bunkum Productions Ltd | Information & communication | 2021 |
| Bupp Loyalty Solutions Ltd | Professional & scientific | 2001 |
| Burdocks Farm Residents Association Limited | Households | 1982 |
| Burgabliss Ltd | Hospitality | 2025 |
| Burger Brothers (UK) Ltd | Hospitality | 2013 |
| Burgess Allen Limited | Administrative & support | 2015 |
| Burgess Consulting Solutions Ltd | Professional & scientific | 2025 |
| Buriton Limited | Professional & scientific | 2021 |
| Burki Group Limited | Administrative & support | 2022 |
| Burleigh Residents Management Limited | Households | 1988 |
| Burling Limited | Real estate | 1993 |
| Burnetts Newsagents Ltd | Wholesale & retail | 2020 |
| Burnt Orange Bars Limited | Hospitality | 2019 |
| Burroughs Day LLP | | 2017 |
| Burt Brill & Cardens Limited | Professional & scientific | 2014 |
| Bushby Care Ltd | Health & social care | 2004 |