| Blue Homes Development Limited | Professional & scientific | 2023 |
| Blue Iris Assets Limited | Real estate | 2022 |
| Blue Nautilus Limited | Professional & scientific | 2017 |
| Blue Park Theatre Company Ltd | Arts & recreation | 2024 |
| Blue Peak Global Ltd | Education | 2025 |
| Blue Planet Education Group Ltd | Administrative & support | 2026 |
| Blue Planet Group Holdings Limited | Information & communication | 2024 |
| Blue Planet IT Limited | Information & communication | 2010 |
| Blue Sail Software Ltd | Information & communication | 2023 |
| Blue Skies (Herts) Ltd | Professional & scientific | 2022 |
| Blue Skies Drone Training Ltd | Education | 2026 |
| Blue Skye Consultancy Ltd | Real estate | 2024 |
| Blue VIX Ltd | Wholesale & retail | 2025 |
| Bluebastion Entertainment Limited | Wholesale & retail | 2026 |
| Bluebell Medical Ltd | Real estate | 2021 |
| Blueberry Consulting & Solutions Design Ltd | Other services | 2013 |
| Blueberry Property Group Ltd | Real estate | 2018 |
| Bluecloudstrade Ltd | Wholesale & retail | 2025 |
| Bluecore Plumbing & Heating Ltd | Construction | 2019 |
| Bluefin Solutions Ltd | Professional & scientific | 2023 |
| Bluen Ltd | Wholesale & retail | 2022 |
| Bluepeak Creative Ltd | Wholesale & retail | 2025 |
| Blueplace Ltd | Real estate | 2020 |
| Blueprint Hour Ltd | Professional & scientific | 2025 |
| Bluethorne International Limited | Construction | 2021 |
| Bluma Jumps Limited | Wholesale & retail | 2020 |
| BLUPRINCE13 Ltd | Information & communication | 2023 |
| Blurosa Ltd | Wholesale & retail | 2025 |
| Blushington Beauty Co Ltd | Other services | 2018 |
| Blythe Meadow (Charsfield) Management Company Limited | Households | 2025 |
| BM and G Limited | Administrative & support | 2019 |
| BM Time Limited | Extraterritorial | 2013 |
| BMA Jewellers Limited | Wholesale & retail | 2026 |
| BMD by Sharon Ltd | Other services | 2017 |
| BME Electrical & Mechanical Services Limited | Construction | 2006 |
| BMG One Solution Services Ltd | Administrative & support | 2025 |
| BMG Payroll Limited | Professional & scientific | 2023 |
| BMG Transport Limited | Transport & logistics | 2023 |
| BML Investing Ltd | Real estate | 2025 |
| Bmyguest Apartments UK Ltd | Real estate | 2024 |
| BNA Group Ltd | Information & communication | 2021 |
| BNH Leisure Ltd | Hospitality | 2018 |
| BNM Ventures Ltd | Wholesale & retail | 2025 |
| Bnovate Technologies Ltd | Administrative & support | 2023 |
| Bnrp Holdings Limited | Wholesale & retail | 2022 |
| Boardwalk Properties Ltd. | Real estate | 2012 |
| Boardwalk Property Developments Ltd | Construction | 2018 |
| BOB Paterson Ltd | Construction | 2025 |
| Bobo Autopart Ltd | Wholesale & retail | 2026 |
| Bobospay Limited | Wholesale & retail | 2025 |
| Bockhill QS Services Ltd | Professional & scientific | 2013 |
| Bodaco Trading Ltd | Wholesale & retail | 2024 |
| Boddevi Ltd | Wholesale & retail | 2023 |
| Bodhichitta Consultancy Limited | Professional & scientific | 2021 |
| Bodla Enterprise Limited | Wholesale & retail | 2025 |
| Body & Mind Coaching Limited | Wholesale & retail | 2008 |
| Body and Mind Healing Therapies Ltd | Health & social care | 2025 |
| Body and Mind Studio International Ltd | Real estate | 2015 |
| Bodymindbalanceuk Ltd | Health & social care | 2021 |
| Bohemia NOW Projects CIC | Health & social care | 2023 |
| Bold APE Ltd | Wholesale & retail | 2024 |
| Bold Horns Ltd | Arts & recreation | 2025 |
| Bold Mining Ltd | Wholesale & retail | 2021 |
| Boldbit Limited | Information & communication | 2011 |
| Bollwerk Ltd | Wholesale & retail | 2024 |
| Bolt Logistics Ltd | Transport & logistics | 2019 |
| Boltjam Ltd | Real estate | 2021 |
| Bonawealth Ltd | Hospitality | 2025 |
| Bonded by Hair Ltd | Other services | 2025 |
| Bonj Ltd | Wholesale & retail | 2024 |
| Bontradeorg Ltd | Professional & scientific | 2014 |
| Bonum Ltd | Information & communication | 2026 |
| Bonza Guide Limited | Information & communication | 2023 |
| Boofee Ltd | Information & communication | 2024 |
| Book Giraffe Ltd | Wholesale & retail | 2025 |
| Boolean Group Ltd | Information & communication | 2026 |
| Boone Design Limited | Other services | 2007 |
| Boortmalt UK Limited | Professional & scientific | 2009 |
| Boost Interactive Ltd | Information & communication | 2025 |
| Boost My Power Ltd | Health & social care | 2019 |
| Boost Swimming Ltd | Wholesale & retail | 2023 |
| Boots on the Ground NW Ltd | Administrative & support | 2025 |
| Borand Media Ltd | Information & communication | 2025 |
| Boredom Buster Ltd | Wholesale & retail | 2026 |
| Borlex Construction Ltd | Construction | 2016 |
| Borntoinvent Limited | Wholesale & retail | 2004 |
| Borrower Guard Ltd | Professional & scientific | 2025 |
| Bosly Ltd | Information & communication | 2025 |
| Boston Care Company Limited | Health & social care | 2009 |
| Boston Roofing Ltd | Construction | 2025 |
| Bosun Marine Ltd | Manufacturing | 2026 |
| BOT Factory Ltd | Information & communication | 2023 |
| Bothakays Consulting Ltd | Professional & scientific | 2024 |
| Botley Governance Ltd | Professional & scientific | 2026 |
| Bouchet Travel Limited | Administrative & support | 2014 |
| Boug Talk Ltd | Professional & scientific | 2012 |
| Boughton Consultancy Limited | Professional & scientific | 2016 |
| Boujee Ltd | Wholesale & retail | 2025 |
| Boulaghrasse Limited | Hospitality | 2015 |
| Boulder Fitness Limited | Arts & recreation | 2023 |