| Bluegrapes Limited | Wholesale & retail | 2009 |
| Bluelane Trading Ltd | Wholesale & retail | 2026 |
| Blueorange Holding Limited | Wholesale & retail | 2023 |
| Blues BOY Records Limited | Wholesale & retail | 2007 |
| Blues Under Limited | Hospitality | 2025 |
| Blumotiv Limited | Manufacturing | 2024 |
| BM Vehicles Ltd | Wholesale & retail | 2020 |
| Bobae Co Ltd | Hospitality | 2025 |
| Bobble Bobo Limited | Real estate | 2022 |
| Boca Hill Limited | Real estate | 2014 |
| Bogatir Ltd | Construction | 2023 |
| Bogea's T&J Ltd | Construction | 2018 |
| Boiler & GAS Works Ltd | Manufacturing | 2021 |
| Boiler Experts Ltd | Manufacturing | 2012 |
| Bold Dragon Ltd | Hospitality | 2017 |
| Bold Rush Solutions Ltd | Administrative & support | 2025 |
| Bolda Limited | Professional & scientific | 2017 |
| Boldshire Limited | Construction | 1988 |
| Bolivar Risk Limited | Administrative & support | 2015 |
| Bolkan Solution Limited | Transport & logistics | 2022 |
| Bollywood Nights Ltd | Administrative & support | 2024 |
| Bolthomes Ltd | Real estate | 2021 |
| Bond Street Consulting Limited | Professional & scientific | 2015 |
| Bondzie Properties Limited | Real estate | 2023 |
| Bonimac Limited | Arts & recreation | 2002 |
| Bonnerhill Ltd | Wholesale & retail | 2002 |
| Book Slam Limited | Arts & recreation | 2009 |
| Bookings Boost Ltd | Professional & scientific | 2022 |
| Bookmouse Ltd | Information & communication | 2025 |
| Boolaky Optics Limited | Health & social care | 2018 |
| Boom London Ltd | Administrative & support | 2014 |
| Boringbits Limited | Professional & scientific | 2019 |
| Borough Presenting Services Limited | Information & communication | 2007 |
| Bostan London Ltd | Construction | 2018 |
| Botanic Enviro Sustainable Innovations Ltd | Wholesale & retail | 2020 |
| Botanika London Limited | Administrative & support | 2020 |
| Botem Services Ltd | Other services | 2016 |
| Boulevard Construction Limited | Construction | 2023 |
| Boulevard Point 1 Limited | Real estate | 2024 |
| Boulevard Point Limited | Real estate | 2023 |
| Bountyhunt Ltd | Information & communication | 2019 |
| Bovingdon Graves Ltd | Real estate | 2019 |
| BOW Limits Limited | Administrative & support | 2014 |
| BOW Riverside Limited | Extraterritorial | 2018 |
| Bowe GP Consulting Limited | Administrative & support | 2014 |
| Bowlboyz Limited | Arts & recreation | 2025 |
| Box House Limited | Real estate | 2025 |
| Box Ltd | Wholesale & retail | 2014 |
| BP UK Solutions Limited | Wholesale & retail | 2026 |
| BPC Boundary Street Limited | Real estate | 2018 |
| BPC Interiors Holdings Limited | Financial services | 2017 |
| BPC Interiors Limited | Administrative & support | 2006 |
| BPC Interiors Properties Limited | Real estate | 2017 |
| BR Workwear Ltd | Manufacturing | 2021 |
| BR12AHS Estates Ltd | Real estate | 2026 |
| Braceyourselflondon.Com Limited | Wholesale & retail | 2017 |
| Bracko Limited | Wholesale & retail | 2022 |
| Brain Audio Limited | Information & communication | 2021 |
| Brainch Development Limited | Construction | 2018 |
| Brains and Hunch Limited | Arts & recreation | 2008 |
| Brainstorrm Heating and Pplumbing Ltd | Construction | 2022 |
| Brainy Beast Media Limited | Arts & recreation | 2013 |
| Bralia Solutions Limited | Information & communication | 2014 |
| Bram Consulting Ltd | Construction | 2011 |
| Brambles Estates Limited | Real estate | 2014 |
| Brandon Costa-Walsh Enterprises Ltd | Financial services | 2025 |
| Brati Hand Car Wash Ltd | Wholesale & retail | 2024 |
| Braxfield Recruitment Limited | Administrative & support | 2016 |
| Breeze Investments Limited | Real estate | 2004 |
| Brian Woolnough (DRY Lining) Limited | Construction | 1996 |
| Bridge Flooring Limited | Construction | 2011 |
| Bridge Supermarket Limited | Wholesale & retail | 2024 |
| Bridge the Water Ltd | Wholesale & retail | 2010 |
| Bridging & Commercial Options Number 1 Ltd | Financial services | 2019 |
| Bridging Range Limited | Education | 2026 |
| Bridgman Ltd | Other services | 2014 |
| Bridgrelite Ltd | Professional & scientific | 2024 |
| Bright Colour Limited | Administrative & support | 2012 |
| Bright Minds Leyton Ltd | Education | 2025 |
| Brighther Living Limited | Real estate | 2026 |
| Brilwyn Investment Co. Limited | Real estate | 1962 |
| Brisket House Ltd | Hospitality | 2024 |
| Bristol Hotel Operating Ltd | Hospitality | 2023 |
| Brit Fusion Group Ltd | Wholesale & retail | 2025 |
| Britannia Acoustic and Fire Ltd | Construction | 2019 |
| Britannia One Ltd | Construction | 2026 |
| Britevents Ltd | Administrative & support | 2023 |
| Britotech Limited | Administrative & support | 2023 |
| Broadoak Gear Cutting and Engineering Ltd | Manufacturing | 2010 |
| Broadoak Investment Ltd | Real estate | 2024 |
| Broadway Close (NOS 1 to 6) Maintenance Limited | Households | 1962 |
| Broadway Estates SH Ltd | Real estate | 2025 |
| Broadway Hair Salon Limited | Other services | 2022 |
| Broadway Music & Vision Limited | Wholesale & retail | 1999 |
| Broadway Rail Limited | Construction | 2014 |
| Bromley & Catford Ltd | Construction | 2013 |
| Bromley Botox Ltd | Health & social care | 2012 |
| Bronx Cheer Limited | Administrative & support | 2015 |
| Bronzerat Records Limited | Arts & recreation | 2007 |
| Brook Project Flooring Limited | Construction | 2026 |