| BSG (South East) Limited | Construction | 2012 |
| BSH Financial Limited | Financial services | 2019 |
| BSL at Work Ltd | Health & social care | 2023 |
| BSM Catering Limited | Hospitality | 2025 |
| Bsnb Limited | Real estate | 2017 |
| BSO Concerts Ltd | Arts & recreation | 2022 |
| BT Carpentry and Construction Group Limited | Manufacturing | 2025 |
| BT Nails Ltd | Other services | 2025 |
| Buchanan Building Services Ltd | Construction | 2021 |
| Buchanan Property Plus Ltd | Construction | 2020 |
| Buchie Limited | Wholesale & retail | 2016 |
| Buckley Movement & Memory Ltd | Arts & recreation | 2026 |
| Budgetmoves Ltd | Transport & logistics | 2017 |
| Bugtown Limited | Information & communication | 2024 |
| Build & Bake Ltd | Manufacturing | 2018 |
| Build Force Talent Ltd | Construction | 2023 |
| Building Diverse Community CIC | Education | 2023 |
| Building Life (UK) Limited | Construction | 2018 |
| Built by the Ridge Ltd | Construction | 2025 |
| Bukka Properties Ltd | Real estate | 2023 |
| Buklan Ltd | Wholesale & retail | 2022 |
| Bulclad Ltd | Construction | 2019 |
| Bullfinch Consultancy Limited | Professional & scientific | 2017 |
| Bullitt Plant Hire Ltd | Administrative & support | 2026 |
| Bulmer Road Industrial Estate Limited | Construction | 2025 |
| Bureautech Ltd | Professional & scientific | 2016 |
| Burgate Lewis Limited | Construction | 2023 |
| Burghill Court Limited | Households | 2006 |
| Burlington Court Residents (Chiswick) Limited | Real estate | 1995 |
| Burn Climb Ltd | Wholesale & retail | 2025 |
| Burnt ASH Food & Wine Limited | Wholesale & retail | 2017 |
| Burnt ASH Primary School | Education | 2015 |
| Burr & Company Limited | Education | 2003 |
| Burrow Festival Ltd | Administrative & support | 2023 |
| Burwell Medical Limited | Health & social care | 2018 |
| Burwood Consulting Ltd | Professional & scientific | 2018 |
| BUS Truck Coach Technical Solutions Limited | Wholesale & retail | 2017 |
| Business Accounting & Advisory Services Limited | Professional & scientific | 2009 |
| Business Bookkeeping Ltd | Professional & scientific | 2015 |
| Business Risk Technology Limited | Professional & scientific | 2013 |
| Business School of Commerce and Management Limited | Education | 2019 |
| Business Solutions (GB) Limited | Extraterritorial | 1998 |
| Businessview Consulting Limited | Other services | 2012 |
| Businessxbridge Ltd | Administrative & support | 2015 |
| Busy Lizzy Nursery Ltd | Education | 2017 |
| Buthro Limited | Households | 2006 |
| Butler Currie & Hook Limited | Professional & scientific | 1983 |
| Butterfly Financial Planning Limited | Professional & scientific | 2017 |
| Buyvero Ltd | Arts & recreation | 2026 |
| Buzzers Academies Ltd | Education | 2023 |
| Buzzers Community CIC | Education | 2024 |
| Buzzers Education Ltd | Education | 2025 |
| BV Medical Consultants Limited | Health & social care | 2010 |
| Bvil Ltd | Manufacturing | 2023 |
| Bvrhsn Communications Ltd | Professional & scientific | 2025 |
| BW Properties (London) Ltd | Administrative & support | 2009 |
| BWE Contractors Ltd | Administrative & support | 2023 |
| BXX Ltd | Construction | 2014 |
| BY Appointment DMC UK Limited | Administrative & support | 2022 |
| BY Design Academy Ltd | Health & social care | 2022 |
| BY Design Aesthetics Ltd | Health & social care | 2022 |
| Byford Ceilings and Partitions Ltd | Construction | 2013 |
| BYG Consultancy Ltd | Information & communication | 2019 |
| Bytesize Consultants Limited | Administrative & support | 2014 |
| Bytla Ltd | Other services | 2023 |
| Byzen Ltd | Construction | 2020 |
| Bébé Garçon Limited | Wholesale & retail | 2018 |
| C & B Finance Limited | Administrative & support | 2005 |
| C & C Property Management Limited | Real estate | 2003 |
| C & G Property Limited | Administrative & support | 2004 |
| C & L M Capital Limited | Real estate | 2025 |
| C & M Property (Boscombe) Limited | Administrative & support | 2011 |
| C & M Ringwood Developments Limited | Construction | 2014 |
| C a T T Properties Limited | Real estate | 2008 |
| C D Spencer Limited | Administrative & support | 2018 |
| C K Wallace Limited | Professional & scientific | 2018 |
| C M & Hannelly Building Services Limited | Construction | 2016 |
| C Stokes Electrical Limited | Construction | 2009 |
| C W Company Secretaries Limited | Professional & scientific | 2002 |
| C&Md Properties Ltd | Real estate | 2022 |
| C&R Hounsome Ltd. | Other services | 2014 |
| C. & M. (Boscombe) Limited | Wholesale & retail | 1981 |
| C.C.F Construction Ltd | Construction | 2020 |
| C.M. Services Limited | Real estate | 1993 |
| C.P. Oblein Limited | Construction | 1973 |
| CA Dental Therapy Ltd | Health & social care | 2023 |
| CA Renovation Ltd | Construction | 2023 |
| CAA Associates Limited | Professional & scientific | 2025 |
| Cabigon Ltd | Health & social care | 2022 |
| Cabinrun Property Management Company Limited | Households | 1994 |
| Cableflow Plumbing & GAS Ltd | Construction | 2026 |
| Cacmac Limited | Real estate | 2025 |
| CAD Scenery Limited | Arts & recreation | 2013 |
| Cadmus Growth Limited | Real estate | 1992 |
| Cadzow Collins Limited | Wholesale & retail | 2017 |
| Caesars Pool Ltd | Wholesale & retail | 2020 |
| Cafe Gilberts Limited | Hospitality | 2025 |
| Cafe Treat Limited | Hospitality | 2018 |
| Cagny House RTM Company Limited | Households | 2023 |
| Cagsak Foods Ltd | Wholesale & retail | 2020 |