| B Levy & Co,(Patterns)Limited | Manufacturing | 1949 |
| B&B Removals and Gardening Limited | Transport & logistics | 2022 |
| B&H London Premium Ltd | Wholesale & retail | 2025 |
| B&P London Limited | Health & social care | 2011 |
| B4TECH Limited | Information & communication | 2017 |
| BA Tuition Ltd | Education | 2024 |
| Baban Trade Limited | Construction | 2020 |
| Babba Box Co Limited | Wholesale & retail | 2019 |
| Back to the Futures Trading Ltd | Financial services | 2009 |
| Bagel Beigel Limited | Hospitality | 2026 |
| Bailey & SON Carpentry Ltd | Construction | 2023 |
| Bakhur Construction Limited | Construction | 2011 |
| Bakiasi Lifts Limited | Manufacturing | 2020 |
| Balance Decoded Ltd | Professional & scientific | 2021 |
| Ballaction London Limited | Real estate | 2004 |
| Ballisticbits Ltd | Wholesale & retail | 2025 |
| Baltaga Limited | Construction | 2026 |
| Bambino Nursery Chigwell Limited | Health & social care | 2023 |
| Barnfield Capital Ltd | Real estate | 2025 |
| Base 1 Ltd | Wholesale & retail | 1991 |
| Basically 154 Limited | Professional & scientific | 2008 |
| Bassi Residential Properties Limited | Real estate | 2026 |
| Battlecat Consulting Limited | Professional & scientific | 2023 |
| Bavas Solutions Ltd | Wholesale & retail | 2015 |
| BB Civils Limited | Construction | 2021 |
| BBS1 Construction Ltd | Construction | 2020 |
| BCO Enterprises Limited | Health & social care | 2016 |
| BD Enterprise UK Limited | Hospitality | 2020 |
| Beaded and Lush Ltd | Wholesale & retail | 2023 |
| Beal Supply and Design Limited | Wholesale & retail | 2013 |
| Beau Loves Limited | Wholesale & retail | 2009 |
| Beautybynimmy Ltd | Other services | 2026 |
| BEE & Walex Ltd | Real estate | 2021 |
| Bench Films Ltd | Information & communication | 2025 |
| Bennerley Road Property Limited | Real estate | 2021 |
| Beon Property Claims Ltd | Construction | 2014 |
| Berry Blossom Homes Ltd | Health & social care | 2024 |
| Best Kebab Chigwell Ltd | Hospitality | 2024 |
| Best Property Group Ltd | Real estate | 2023 |
| Bestlocks-London Ltd | Manufacturing | 2025 |
| Bexim Limited | Extraterritorial | 2010 |
| BGS Books Ltd | Information & communication | 2005 |
| Bharat Investment Chigwell Limited | Real estate | 2014 |
| Bharuch to Bombay Ltd | Hospitality | 2023 |
| Bicyclewanders Ltd | Administrative & support | 2025 |
| Bidu Ltd | Construction | 2016 |
| Bigaloe & Co. Ltd | Health & social care | 2011 |
| Binta Patel Ltd | Other services | 2020 |
| Birsen & Deniz Ltd | Other services | 2023 |
| Bizcrafto Ltd | Wholesale & retail | 2026 |
| Black Aurora Consulting Ltd | Information & communication | 2025 |
| Blessed Care Group Ltd | Other services | 2024 |
| Blind Massage Ltd | Other services | 2023 |
| Blofeld Limited | Arts & recreation | 2018 |
| Blossom Gardens London Limited | Administrative & support | 2018 |
| Blue 6 Services Limited | Construction | 2020 |
| Blue Triangle Solutions Ltd | Other services | 2015 |
| Bluelake Properties Ltd | Real estate | 2017 |
| Blueprinted Solutions Limited | Administrative & support | 2012 |
| Bohemia Hastings LLP | | 2015 |
| Bolduresti Services Ltd | Construction | 2021 |
| Bolton Topco Limited | Financial services | 2021 |
| Boundary Passage Limited | Real estate | 2019 |
| Bowls Residents Association Limited(The) | Administrative & support | 1967 |
| BQR Social Ltd | Professional & scientific | 2025 |
| BR1CK Ltd | Administrative & support | 2024 |
| BRA Construction Ltd | Construction | 2024 |
| Bradshaw Stairlifts Ltd | Manufacturing | 2016 |
| Braille Pages Ltd | Manufacturing | 2023 |
| Braniff Plumbing and Heating Limited | Construction | 2023 |
| Brave Dental Sedation Ltd | Health & social care | 2025 |
| Breen Business Services Limited | Administrative & support | 1991 |
| Brendon 21 Limited | Financial services | 2025 |
| Brikhaus Holdings Ltd | Real estate | 2025 |
| Bristol Prime Properties Ltd | Real estate | 2023 |
| Brix Subs Limited | Hospitality | 2019 |
| Brook Buds Limited | Other services | 2008 |
| Brook Way Consultancy Limited | Professional & scientific | 2021 |
| Brookshill Properties Limited | Real estate | 2012 |
| Brow Genie Limited | Other services | 2019 |
| Brucohen Ltd | Health & social care | 2021 |
| Brunch Cafe and Bakery Ltd | Manufacturing | 2026 |
| Brunswick Hainault Ltd | Real estate | 2025 |
| BSF BI Data Solutions Ltd | Information & communication | 2023 |
| BSK Care (UK) Ltd | Health & social care | 2020 |
| BT Real Estate Limited | Real estate | 2025 |
| Bttf Investments Limited | Real estate | 2024 |
| Buff & Polish (Chigwell) Limited | Health & social care | 2017 |
| Build IT Construction Limited | Construction | 2016 |
| Build Tech Contractors Ltd | Construction | 2023 |
| Buildvantage (Balham) Ltd | Construction | 2024 |
| Buildvantage (Freehold) Limited | Real estate | 2016 |
| Buildvantage (Oak House) Limited | Real estate | 2015 |
| Buildvantage (Pioneer House) Limited | Real estate | 2015 |
| Buildvantage (Plumstead) Ltd | Construction | 2024 |
| Buildvantage (Queensbury) Limited | Construction | 2022 |
| Buildvantage (Woolwich) Limited | Real estate | 2022 |
| Buildvantage Limited | Real estate | 2012 |
| Buildvantage Management Limited | Real estate | 2023 |
| Built Through Reputation Services Ltd | Construction | 2018 |