| Boundless Innovation Limited | Other services | 2016 |
| Bourdeau Industries Ltd | Arts & recreation | 2003 |
| Bourne Property Developments Limited | Construction | 1987 |
| Boutique Modern Limited | Manufacturing | 2010 |
| BOW WOW the Dog Chop Ltd | Wholesale & retail | 2022 |
| Bowerheath Holdings Ltd | Professional & scientific | 2006 |
| Bowerheath Limited | Real estate | 1999 |
| Bowhill Estate Management Company Limited | Households | 2018 |
| Bowhill Homes Ltd | Real estate | 2015 |
| Bowhill Properties Limited | Real estate | 2023 |
| Bowled Over Media Ltd | Information & communication | 2018 |
| Bowmar Ltd | Real estate | 2014 |
| Box & Go Limited | Hospitality | 2026 |
| Box 2 Holdings Ltd | Financial services | 2020 |
| Box Hill Services Ltd | Professional & scientific | 2009 |
| Box OUT Holdings Ltd | Extraterritorial | 2019 |
| Box OUT Records Limited | Information & communication | 2003 |
| Boxless Ltd | Professional & scientific | 2023 |
| Boxvn Limited | Transport & logistics | 2018 |
| Boxwell Road LLP | | 2011 |
| BOY Hudson Ltd | Information & communication | 2020 |
| Boyle & Perks Limited | Arts & recreation | 2012 |
| Boyne and Holland Technology Services Limited | Information & communication | 2025 |
| Boyne Consultancy Services Ltd | Administrative & support | 2018 |
| Bozboz Ltd | Information & communication | 2008 |
| BP Research Consultancy Ltd | Professional & scientific | 2002 |
| Bpat Limited | Construction | 2010 |
| BPL Realisations Limited | Health & social care | 2013 |
| BPM (Architectural Services) Limited | Professional & scientific | 2008 |
| BPS Solicitors Limited | Professional & scientific | 2017 |
| BPT Construction Group Limited | Construction | 2025 |
| BR Construction & Roofing Ltd | Construction | 2025 |
| BR19HTON Ltd | Information & communication | 2022 |
| Bradbury Electrical Contractors Ltd | Construction | 2013 |
| Bradbury Electrical Holdings Ltd | Financial services | 2024 |
| Bradbury Residential Management Limited | Real estate | 2017 |
| Braddock International Ltd | Administrative & support | 2015 |
| Bradford Flats Limited | Construction | 2017 |
| Bradford Haulage Limited | Transport & logistics | 2018 |
| Bradley Dyer Media Limited | Professional & scientific | 2002 |
| Bradley Ralph Property Limited | Real estate | 2023 |
| Bradley Stewart International Limited | Wholesale & retail | 2020 |
| Braemore Court Investments Limited | Households | 1985 |
| Braiden Accounts Limited | Professional & scientific | 2025 |
| Braiden Construction Limited | Professional & scientific | 2014 |
| Braillard Training Limited | Administrative & support | 2010 |
| Brainbath Studios Ltd | Arts & recreation | 2025 |
| Brainwaves Ventures Company Limited | Professional & scientific | 2000 |
| Braken Medical Limited | Professional & scientific | 2025 |
| Bramber Bakehouse | Manufacturing | 2015 |
| Bramber Brooks Limited | Wholesale & retail | 2016 |
| Bramber Close Seaford Limited | Households | 2006 |
| Bramble Care Homes Limited | Health & social care | 1996 |
| Brambletyne Court Limited | Households | 2013 |
| Bramptons Legacy LLP | | 2024 |
| Bramwell Asset Management Limited | Real estate | 2026 |
| Bramwell Capital Group Limited | Financial services | 2026 |
| Bramwell Healthcare Limited | Health & social care | 2026 |
| Bramwellbrand Productions Ltd | Arts & recreation | 2024 |
| Brand F Limited | Arts & recreation | 2005 |
| Brand Ptty LLP | | 2025 |
| Brand Skout Limited | Wholesale & retail | 2013 |
| Brand ZED Ltd | Professional & scientific | 2024 |
| Brandb Rad!O Ltd | Information & communication | 2024 |
| Branded Sport Limited | Professional & scientific | 2003 |
| Brandenburger Management Ltd | Professional & scientific | 2024 |
| Brandover Ltd | Professional & scientific | 2026 |
| Brandsdale Limited | Real estate | 2015 |
| Brandstencil Ltd | Information & communication | 2019 |
| Brandzooh Ltd | Financial services | 2019 |
| Brangwyn Avenue LLP | | 2012 |
| Brantford FOX Limited | Professional & scientific | 2023 |
| Brantridge Properties Limited | Real estate | 2013 |
| Brasil Online Limited | Wholesale & retail | 2024 |
| Brass Monkey Ice Cream Ltd | Manufacturing | 2017 |
| Brave Traveller Games Ltd | Information & communication | 2023 |
| Bravo One Media Ltd | Administrative & support | 2015 |
| Braybon Yard Management Company Limited | Real estate | 2013 |
| Breach Investments Limited | Real estate | 2020 |
| Bread & Honey Brighton Limited | Hospitality | 2022 |
| Bread & Milk Ltd | Hospitality | 2011 |
| Bread of Brighton Ltd | Hospitality | 2017 |
| Breakeven Awareness and Training CIC | Health & social care | 2022 |
| Breakeven Counselling Ltd | Health & social care | 2014 |
| Breaking Through the Barriers Ltd | Information & communication | 2013 |
| Breakingwaters Media Ltd | Information & communication | 2026 |
| Breakthrough Software Limited | Information & communication | 2005 |
| Breakthrough Therapy Ventures Ltd | Financial services | 2022 |
| Breakwater Limited | Professional & scientific | 2018 |
| Breathe Hbot Limited | Health & social care | 2025 |
| Breathe MEN CIC | Health & social care | 2022 |
| Breathe Wellbeing Ltd | Health & social care | 2025 |
| BREATHE123 Ltd | Wholesale & retail | 2025 |
| Breden Brands Ltd | Wholesale & retail | 2026 |
| Breem Construction Limited | Construction | 2012 |
| Brentbury Limited | Professional & scientific | 2021 |
| Brett James Conservation Limited | Other services | 2013 |
| Brett Ryder Ltd | Professional & scientific | 2006 |
| Brewbyte Ltd | Information & communication | 2024 |
| Brewery Yard Freehold Company Limited | Households | 2019 |