| Beyond Boundaries Travel Ltd | Administrative & support | 2025 |
| Beyond Marketing AI Ltd | Information & communication | 2025 |
| Beyond the Brij Ltd | Health & social care | 2026 |
| Beyond the Fringe 183 Ltd | Other services | 2015 |
| BEZ Solutions Ltd | Professional & scientific | 2011 |
| Beznexx Technologies Limited | Information & communication | 2025 |
| BF01 Limited | Construction | 2024 |
| Bfcr Management Company Limited | Households | 2015 |
| BFW Gym & Developments Limited | Construction | 2021 |
| BFW Properties Limited | Real estate | 2022 |
| BG Construction Solutions Ltd | Professional & scientific | 2017 |
| BH (Freehold) Limited | Real estate | 2016 |
| BH Education Limited | Education | 2022 |
| Bhandari Group Ltd | Real estate | 2020 |
| Bharti Software Ltd | Information & communication | 2011 |
| Bhaw Properties Ltd | Real estate | 2019 |
| BHG Advisers Limited | Professional & scientific | 2007 |
| Bianco Gelato Patisserie Limited | Wholesale & retail | 2023 |
| Bibbegan Investments Ltd | Financial services | 2025 |
| Big BAD Great Big Ltd | Information & communication | 2018 |
| Big Bear Forest School Ltd | Education | 2026 |
| Big Big Train Productions Limited | Information & communication | 2019 |
| Big Big Train Touring LLP | | 2023 |
| Big Blue Audio Limited | Extraterritorial | 2009 |
| Big Games Shop Ltd | Wholesale & retail | 2022 |
| Big Picture Wealth Planning Ltd | Financial services | 2017 |
| Biga Group UK Limited | Information & communication | 2022 |
| Bill Kear (Plant Hire) Limited | Professional & scientific | 1989 |
| Bill Kear Plant & Agricultural Contractors Limited | Construction | 1982 |
| Billy Basin Limited | Other services | 1999 |
| Bioreg UK Limited | Professional & scientific | 2014 |
| Birch Riddle & Co Limited | Professional & scientific | 2003 |
| Birchdene Ltd | Real estate | 2016 |
| Bird Residents Company Limited | Households | 1973 |
| Birkett Hall Developments Limited | Construction | 2024 |
| Birkett Hall Homes Limited | Construction | 2024 |
| Birkmyre Park Ltd | Information & communication | 2019 |
| Birley Moor Management Company Limited | Real estate | 2017 |
| Birrusdale Limited | Administrative & support | 2015 |
| Birth Instinct Limited | Health & social care | 2012 |
| Bishop Architects Limited | Professional & scientific | 2020 |
| Bite ME Street Foods Limited | Hospitality | 2025 |
| Bitec Services Ltd | Professional & scientific | 2025 |
| Bites Media Ltd | Administrative & support | 2009 |
| Bitprof Ltd | Professional & scientific | 2016 |
| Bits Trading Limited | Real estate | 2020 |
| Bizprof Ltd | Information & communication | 2011 |
| BJ Refurbishment Limited | Construction | 2016 |
| Black Isle Engineering Ltd | Professional & scientific | 2019 |
| Black Kite Search Limited | Administrative & support | 2015 |
| Black Panda Paya Ltd | Hospitality | 2024 |
| Black Square Capital Ltd | Professional & scientific | 2014 |
| Black Star Pubs Ltd | Hospitality | 2022 |
| Black Wheels Chauffeurs Limited | Transport & logistics | 2026 |
| Black Wolf Global Ltd | Wholesale & retail | 2024 |
| Blackall Court Limited | Households | 2002 |
| Blackbox Technologies Limited | Information & communication | 2001 |
| Blackbrook Interiors Ltd | Wholesale & retail | 2018 |
| Blackbrook Kitchens Ltd | Wholesale & retail | 2018 |
| Blackclip Limited | Construction | 2015 |
| Blackheart Management Ltd | Professional & scientific | 2020 |
| Blackridge Installations Ltd | Construction | 2026 |
| Blacks Burgers Franchise Ltd | Hospitality | 2018 |
| Blackwood Fashion Investments Limited | Wholesale & retail | 2020 |
| Bladerunner Limited | Health & social care | 2000 |
| Blaze Rigging Ltd | Construction | 2025 |
| Bledi Construction Ltd | Administrative & support | 2017 |
| Blendstyle Limited | Real estate | 2000 |
| Blenheim Court Residents RTM Company Limited | Households | 2013 |
| Blenheim High School | Education | 2012 |
| Blenheim Roofing Services Limited | Construction | 1997 |
| Bleu Homes Ltd | Construction | 2020 |
| Bleuivy 24 Ltd | Real estate | 2024 |
| Bloc Architects Limited | Professional & scientific | 2023 |
| Blocdoc Ltd | Health & social care | 2019 |
| Blocdoc Services LLP | | 2019 |
| Blocked Gutters Ltd | Administrative & support | 2019 |
| Bloomvie Ltd | Information & communication | 2026 |
| Blossom and Bloom Consultancy Limited | Professional & scientific | 2012 |
| Bloxworth Close (Freehold) Limited | Households | 2006 |
| BLU Labs Ltd | Information & communication | 2026 |
| Blue Builds & Design Ltd | Professional & scientific | 2023 |
| Blue Cloud Graphics Ltd | Manufacturing | 2020 |
| Blue Interiors Limited | Construction | 2010 |
| Blue Line Boilers Ltd | Construction | 2026 |
| Blue Lobster Investments Limited | Real estate | 2023 |
| Blue Roofing Ltd | Construction | 2024 |
| Blue Seas (Consulting) Limited | Professional & scientific | 2012 |
| Blue Zebra Strategy Limited | Professional & scientific | 2015 |
| Bluechip Heating Limited | Construction | 2007 |
| Blueflame Boilers Ltd | Construction | 2020 |
| Bluegates Management Company Limited | Households | 1990 |
| Blueroc Estates Ltd | Real estate | 2021 |
| Bluescape Design, Planning & Construction Limited | Construction | 2014 |
| Bluestar Care Services Limited | Health & social care | 2024 |
| Blustack Limited | Wholesale & retail | 2023 |
| Bmak Investments Limited | Professional & scientific | 2007 |
| BMR Energy and Property Consultants Ltd | Construction | 2022 |
| BOB Barnett Holdings Limited | Financial services | 2020 |
| Bobtec Ltd | Information & communication | 2016 |