| Buckley Law Limited | Professional & scientific | 2017 |
| Buddhi Capital Ltd | Real estate | 2020 |
| Buddhi Horizons Ltd | Professional & scientific | 2025 |
| Budget Green Homes Ltd | Real estate | 2024 |
| Bugalter & Co Ltd | Professional & scientific | 2018 |
| Buhay Paving Ltd | Construction | 2015 |
| Build and Renovation Contractors Ltd | Construction | 2026 |
| Build Art Construction Ltd | Construction | 2023 |
| Builder & Decorator Ltd | Construction | 2012 |
| Builders in TIE Ltd | Construction | 2025 |
| Building Cons OJI Ltd | Construction | 2025 |
| Building Control Inspectors Limited | Construction | 2021 |
| Building EMP (Barnet) Limited | Construction | 2014 |
| Building EMP (London) Ltd | Construction | 2019 |
| Building Empire Ltd | Other services | 2012 |
| Building Protection Ltd | Construction | 2019 |
| Building the World Limited | Construction | 2025 |
| Buildvolt Ltd | Construction | 2025 |
| Buildwell Abodes Limited | Construction | 2022 |
| Buildwise Core Construction Ltd | Construction | 2026 |
| Bulgarian Food Pirin Ltd | Wholesale & retail | 2023 |
| Bulldog Locksmiths Limited | Manufacturing | 2021 |
| Bullgate Ltd | Real estate | 2018 |
| Bumbar Construction Ltd | Construction | 2024 |
| BUN Rush Ltd | Hospitality | 2025 |
| Bunea.Pat Ltd | Other services | 2017 |
| Burgeon Sourcing Ltd | Wholesale & retail | 2022 |
| Burlington Management Limited | Real estate | 2015 |
| Burman Global Enterprises Limited | Wholesale & retail | 2002 |
| Burnt Oak Ltd | Construction | 2025 |
| Burrow & Bound Ltd | Real estate | 2025 |
| Burrows Health Project CIC | Public administration | 2025 |
| Bush Brush Cleaners Ltd | Administrative & support | 2006 |
| Business Academy for Development, Execution and Ascension Ltd | Information & communication | 2025 |
| Business Strategy Development Ltd | Professional & scientific | 2014 |
| Butcher & More Limited | Real estate | 2025 |
| Butlers Fine Foods & Provisions Limited | Wholesale & retail | 2014 |
| Butlers Mews (Block F) Management Company Limited | Households | 1989 |
| Butnariu Ltd. | Transport & logistics | 2018 |
| Buttercups London Ltd | Wholesale & retail | 2020 |
| Butu Construction Ltd | Construction | 2019 |
| Buy a Warranty Limited | Administrative & support | 2016 |
| Buy and Sell International . COM Limited | Wholesale & retail | 2025 |
| Buy to LET Holdings Ltd | Real estate | 2020 |
| Buybigbrands Ltd | Wholesale & retail | 2020 |
| Buzzar Traders Ltd | Wholesale & retail | 2020 |
| BVI Construct Ltd | Construction | 2017 |
| BVJ Solutions Limited | Administrative & support | 2023 |
| BW Childcare Limited | Health & social care | 2025 |
| BY Alessia Ltd | Professional & scientific | 2024 |
| BY Shirin Ltd | Wholesale & retail | 2025 |
| BYF Limited | Wholesale & retail | 2017 |
| Byhy Limited | Wholesale & retail | 2025 |
| BYL Support CIC | Real estate | 2025 |
| Bylcars Limited | Transport & logistics | 2024 |
| Byran Three Limited | Real estate | 2025 |
| Byron Healthcare Ltd | Health & social care | 2021 |
| Byron Medical Ltd | Health & social care | 2022 |
| Byrosemarydesigns Ltd | Wholesale & retail | 2021 |
| Byrow Ltd | Information & communication | 2022 |
| BYZ Limited | Wholesale & retail | 2023 |
| Byzpulse Ltd | Professional & scientific | 2015 |
| Bzbeez Ltd | Wholesale & retail | 2022 |
| C & C Laundry Services Limited | Other services | 2017 |
| C & P Tailors Limited | Manufacturing | 2012 |
| C & R Motors Limited | Wholesale & retail | 2002 |
| C 4 S Security Ltd | Wholesale & retail | 2023 |
| C C M Builders Ltd | Construction | 2016 |
| C F Mechanical Services Ltd | Manufacturing | 2013 |
| C H S Building & Engineering Services Limited | Construction | 1985 |
| C L Beauty Ltd | Other services | 2025 |
| C OJE Lifting Services Ltd | Other services | 2017 |
| C R Odedra Limited | Wholesale & retail | 2021 |
| C Tanasa Ltd | Construction | 2014 |
| C&B Brickwork Ltd | Administrative & support | 2016 |
| C&K Building Services Ltd | Construction | 2014 |
| C&T Absolute Services Ltd | Construction | 2022 |
| C&V Building Ltd | Construction | 2017 |
| C&V Unique Properties Ltd | Real estate | 2023 |
| C11 Capital Ltd | Financial services | 2025 |
| C5S Medical Limited | Health & social care | 2021 |
| Caathins Property Services Ltd | Real estate | 2021 |
| CAB Extra Ltd | Wholesale & retail | 2019 |
| Cabhubz Limited | Transport & logistics | 2025 |
| Cactus Grill Ltd | Other services | 2012 |
| Caddington Golf Club Limited | Arts & recreation | 2007 |
| Caelion Ltd | Administrative & support | 2026 |
| Caerus Lifecare Limited | Health & social care | 2017 |
| Cafe Race Ltd | Hospitality | 2019 |
| Caffly Ltd | Wholesale & retail | 2025 |
| Caher Ltd | Hospitality | 2025 |
| Cake Box (Wembley) Ltd | Hospitality | 2012 |
| Cake Box Acton Ltd | Wholesale & retail | 2020 |
| Cake Box Cricklewood Ltd | Wholesale & retail | 2019 |
| Cake Shepherds Bush Ltd | Wholesale & retail | 2024 |
| Cakes & Flakes Ltd | Hospitality | 2021 |
| Caldera Holdings Ltd | Professional & scientific | 2022 |
| California Design Limited | Manufacturing | 2025 |
| California Property Ltd | Real estate | 2010 |
| Calin Nico Ltd | Transport & logistics | 2017 |