| Banna Medical Services Limited | Health & social care | 2012 |
| Bansols 121 Limited | Extraterritorial | 2019 |
| Bansols 123 Limited | Administrative & support | 2021 |
| Bansols 124 Limited | Extraterritorial | 2024 |
| Bansols Beta Limited | Hospitality | 1993 |
| Bansols Directors Limited | Extraterritorial | 1997 |
| Bansols Sixty-Two Limited | Extraterritorial | 2012 |
| Bansubs Ltd | Wholesale & retail | 2023 |
| Bantu Cares Ltd | Health & social care | 2019 |
| Bar Stuff Limited | Extraterritorial | 2003 |
| Barclay Residents Company Limited | Households | 1986 |
| Barefoot Media Ltd | Information & communication | 2025 |
| Barker & Evans Holdings Limited | Financial services | 2023 |
| Barker & Evans Limited | Construction | 1972 |
| Barn Farm Plants Limited | Wholesale & retail | 2011 |
| Barnby Ltd | Transport & logistics | 2026 |
| Barnstones Consulting Ltd | Professional & scientific | 2024 |
| Barrett Water Ltd | Water & waste | 2018 |
| Barrington Office (Brackley) Limited | Administrative & support | 2024 |
| Barrow Hill Music Limited | Information & communication | 2014 |
| Barry Callebaut (UK) Limited | Manufacturing | 1985 |
| Barry Callebaut Holding (UK) Limited | Manufacturing | 1990 |
| Barry Gaye Limited | Health & social care | 2022 |
| Bart Van ES Books Ltd | Information & communication | 2024 |
| Bartec Services Ltd | Manufacturing | 2025 |
| Bartholomew Street Developments Limited | Real estate | 2006 |
| Barton Hughes Transport Ltd | Transport & logistics | 2022 |
| Barton Willow Ltd | Financial services | 2024 |
| Barwell Property Services Ltd | Construction | 2022 |
| Base Performance Simulators Ltd | Manufacturing | 2009 |
| Basesettom Ltd | Financial services | 2021 |
| Bash Developments Ltd | Wholesale & retail | 2022 |
| Bassi Electrical Limited | Construction | 2018 |
| Bath Masonry Ltd | Manufacturing | 2021 |
| Batool Express Ltd | Administrative & support | 2022 |
| Battery Celler Ltd | Wholesale & retail | 2012 |
| Baty & Wenman Limited | Real estate | 2015 |
| Bavajees Ltd | Manufacturing | 2025 |
| Baykoch 2349 UK Ltd | Real estate | 2021 |
| BB Creative Studio Ltd | Professional & scientific | 2024 |
| BB Strategy Ltd | Professional & scientific | 2024 |
| BB Wine Store Limited | Wholesale & retail | 2017 |
| BB4 Hospitality Limited | Hospitality | 2017 |
| BC & J W Associates Ltd | Professional & scientific | 2017 |
| BC Executive Assistance Ltd | Information & communication | 2024 |
| BC Nail Spa Ltd | Other services | 2026 |
| BDS Couriers Limited | Transport & logistics | 2019 |
| BDT Holdings Limited | Financial services | 2017 |
| BE Portable Ltd | Wholesale & retail | 2016 |
| Beacon Dynamic Services Ltd | Professional & scientific | 2025 |
| Beaqua Ltd | Wholesale & retail | 2023 |
| Bear Gaming Ltd | Wholesale & retail | 2022 |
| Bear Instruments Ltd | Professional & scientific | 2016 |
| Beauchamp Ventures Limited | Hospitality | 2024 |
| Beaumont Court (Banbury) Property Management Limited | Households | 1987 |
| Beaumont Limited | Professional & scientific | 1993 |
| Beaumont Photography Group Limited | Financial services | 2015 |
| Beautique Events Ltd | Professional & scientific | 2021 |
| Beauty 365(UK) Ltd | Other services | 2026 |
| Beauty Studio (Oxon) Ltd | Other services | 2024 |
| Beauty Through Balance Limited | Other services | 2026 |
| Beauty Within Professional Beauty Therapy Ltd | Other services | 2003 |
| Beauty&Nova Limited | Manufacturing | 2015 |
| Beck Building Limited | Construction | 2013 |
| BEE Asset Holdings Ltd | Construction | 2026 |
| Beecham Rail Engineers (BRE) Limited | Professional & scientific | 2007 |
| Beechfield House Residents Management Limited | Households | 2015 |
| Beechies Limited | Professional & scientific | 2025 |
| Beerling Business Services Ltd | Professional & scientific | 2018 |
| Behaviour Change Ltd | Other services | 2009 |
| Belfer&Co Ltd | Wholesale & retail | 2021 |
| Bell Supply UK Ltd | Wholesale & retail | 2026 |
| Bella and Buddy Ltd | Extraterritorial | 2016 |
| Bella Cherry Ltd | Other services | 2025 |
| Bellagio Limousine Limited | Administrative & support | 2023 |
| Belle Hair N Beauty Ltd | Other services | 2026 |
| Bellenden Road Ltd | Households | 2007 |
| Belport (Exning) Limited | Real estate | 2022 |
| Belport Active Management Strategy LLP | | 2023 |
| Belport Adlington Ltd | Real estate | 2023 |
| Belport Adlington Opco Ltd | Real estate | 2023 |
| Belport AMA Limited | Real estate | 2019 |
| Belport Capital Ltd | Real estate | 2023 |
| Belport Estates Limited | Agriculture & fishing | 2022 |
| Belport Investors LLP | | 2023 |
| Belport Limited | Real estate | 2016 |
| Belushi Limited | Wholesale & retail | 2002 |
| BEN Quarman Electrical Ltd | Construction | 2016 |
| BEN Window Cleaning Ltd | Manufacturing | 2021 |
| Bench Grade Brands Group Ltd | Wholesale & retail | 2026 |
| Benchmark Operations Limited | Professional & scientific | 2024 |
| Benchmarker Ltd | Information & communication | 2011 |
| Benford Commercial Services Limited | Professional & scientific | 2019 |
| Bengal Spice Oxford Limited | Hospitality | 2022 |
| Bengal Spice Private Ltd | Hospitality | 2018 |
| Beniaminprintesa Limited | Construction | 2023 |
| Benk Solutions Ltd | Health & social care | 2013 |
| Bennett B2B Limited | Professional & scientific | 2018 |
| Bensons Barn Ltd | Agriculture & fishing | 2024 |
| Bensons Forge Ltd | Agriculture & fishing | 2024 |