| Buckhurst Management Ltd | Households | 2011 |
| Buckinghamshire Medical Limited | Health & social care | 2023 |
| Buckinghamshire Urology Partnership LLP | | 2024 |
| Buckland and Woodward Plumbing and Heating Services Ltd | Construction | 2019 |
| Buckler Productions Ltd | Professional & scientific | 2004 |
| Buckley and Lynn Limited | Construction | 2018 |
| Buckley Place Management 2013 Limited | Real estate | 2013 |
| Buddies Pet Grooming Spa & Academy Ltd | Professional & scientific | 2023 |
| Budgie Healthcare Limited | Health & social care | 2022 |
| Budgies Tyre Services Limited | Wholesale & retail | 2018 |
| Buds & Spuds Ltd | Wholesale & retail | 2026 |
| Buds Property Holdings Limited | Professional & scientific | 2003 |
| Buffalo Crow Ltd | Mining & quarrying | 2012 |
| Build a Drive Limited | Construction | 2018 |
| Build Solutions Essex Ltd | Construction | 2025 |
| Build Utopia Ltd | Construction | 2015 |
| Build Your Dream Kitchen and Bathrooms Limited | Wholesale & retail | 2024 |
| Buildclip Limited | Real estate | 2004 |
| Building Awesome Futures Ltd | Professional & scientific | 2024 |
| Building Link Limited | Wholesale & retail | 1999 |
| Buildings Brothers Constructions Ltd | Construction | 2019 |
| Buildviser Ltd | Construction | 2023 |
| Bula Pacific Travel & Shipment Ltd | Transport & logistics | 2020 |
| Bulford Music Ltd | Information & communication | 2022 |
| Bullion Services Limited | Administrative & support | 2025 |
| Bullock Agricultural Limited | Administrative & support | 2024 |
| Bullock Plant Ltd | Extraterritorial | 2006 |
| Bulmer Brick Cutting Limited | Extraterritorial | 2015 |
| Bumble BEE Enterprise Limited | Financial services | 2017 |
| Bumblebeepsychology Ltd | Health & social care | 2025 |
| Bumpstead Maltings Ltd | Construction | 2023 |
| Bunny Property Holdings Ltd | Real estate | 2025 |
| Bunting & Sons (1820) Limited | Extraterritorial | 2014 |
| Buntings Fine Foods Ltd | Wholesale & retail | 2010 |
| Burdett Metals Ltd | Wholesale & retail | 2013 |
| Burdon Family Holdings Limited | Other services | 2025 |
| Burgess Industrial Group Ltd | Financial services | 2016 |
| Burke JIC Services Ltd | Other services | 2018 |
| Burkitt Holdings Limited | Administrative & support | 2025 |
| Burleigh Management Limited | Financial services | 2013 |
| Burleighone Limited | Financial services | 2022 |
| Burley Catering Consultancy Limited | Professional & scientific | 2017 |
| Burn Capital Limited | Financial services | 2017 |
| Burnden Pepper Limited | Financial services | 2006 |
| Burnham Hope Holdings Limited | Financial services | 2017 |
| Burnham Hope Properties Ltd | Real estate | 2021 |
| Burning Platform Limited | Professional & scientific | 2006 |
| Burns Court (Gidea Park) Management Company Limited | Households | 2019 |
| Burrs Elite Equine Ltd | Extraterritorial | 2018 |
| Burstar Solutions Ltd | Administrative & support | 2015 |
| Bursuc Construction Ltd | Construction | 2025 |
| Burton Meadow Management Limited | Households | 2019 |
| Burton Roofing Ltd | Construction | 2026 |
| Bury L&P Sushi Ltd | Hospitality | 2025 |
| Busbywebb Limited | Professional & scientific | 2014 |
| Bush Property (Essex) Ltd | Real estate | 2023 |
| Bushey Mill Properties Ltd | Real estate | 2021 |
| Bushgrove Property Limited | Real estate | 2017 |
| Bushra Elzubeir Limited | Financial services | 2025 |
| Business & Finance Consulting Ltd | Professional & scientific | 2012 |
| Business & Technology Management Limited | Information & communication | 2011 |
| Business and Tourist Visas Limited | Professional & scientific | 2012 |
| Business Champion Accountants Ltd | Professional & scientific | 2018 |
| Business Data Applications Limited | Real estate | 1990 |
| Business Harmonics Limited | Professional & scientific | 2005 |
| Business Kids Essex Ltd | Education | 2023 |
| Business Made Simpler Limited | Professional & scientific | 2026 |
| Business Overhead Solutions Limited | Administrative & support | 2016 |
| Business Performance Therapy Limited | Health & social care | 2024 |
| Business Weave Limited | Information & communication | 2001 |
| Buskerteers Choir Ltd | Information & communication | 2014 |
| Busybee Properties Ltd | Real estate | 2021 |
| Busybee Pursuits Ltd | Health & social care | 2016 |
| Butt Road Convenience Limited | Wholesale & retail | 2025 |
| Butterflies and Bubbles Sensory Ltd | Health & social care | 2023 |
| Butterflys Care Homes Ltd | Health & social care | 2008 |
| Butters John BEE Limited | Real estate | 2004 |
| Button Sand 1 LLP | | 2003 |
| Button Sand 2 LLP | | 2022 |
| Buttons Financing Ltd | Financial services | 2021 |
| Buxerve Ltd | Construction | 2013 |
| Buxton Acquisitions Limited | Real estate | 2022 |
| Buxton Close (Stansted Mountfitchet) Management Company Limited | Households | 2024 |
| Buxton Flow Screeds Limited | Construction | 2018 |
| Buy OFF Peak Limited | Extraterritorial | 2000 |
| Buy Tyres Ltd | Extraterritorial | 2011 |
| Buyerdock Ltd | Information & communication | 2019 |
| Buyermax Hook Ltd | Wholesale & retail | 2025 |
| Buytolet Limited | Financial services | 2015 |
| Buzz Power Ltd | Wholesale & retail | 2021 |
| BV10 Limited | Financial services | 2019 |
| BV100 Limited | Financial services | 2019 |
| BV101 Limited | Financial services | 2019 |
| BV102 Limited | Financial services | 2022 |
| BV103 Limited | Financial services | 2023 |
| BV104 Limited | Financial services | 2025 |
| BV8 Limited | Financial services | 2019 |
| BW Air and Energy Solutions Ltd | Construction | 2023 |
| BW Operations Limited | Information & communication | 2024 |
| Bwedevents Ltd | Administrative & support | 2026 |