| Basement Waterproofing Consultants Limited | Professional & scientific | 2023 |
| Basementartsproject CIC | Arts & recreation | 2022 |
| Basewheel Limited | Wholesale & retail | 2004 |
| Baseworks Ltd | Construction | 2009 |
| Bash & Smash Body Fitness Limited | Arts & recreation | 2017 |
| Bash Cleaning Solutions Ltd | Administrative & support | 2024 |
| Bash Hires Ltd | Transport & logistics | 2024 |
| Bash Recycles Limited | Water & waste | 2026 |
| Bashart Pharma Ltd | Wholesale & retail | 2025 |
| Bashirsons Limited | Real estate | 2003 |
| Bashon Properties Ltd | Real estate | 2024 |
| Basi Retrofit Services Ltd | Construction | 2022 |
| Basia Design Ltd | Wholesale & retail | 2024 |
| Basil & Pearl Enterprises Ltd | Real estate | 2023 |
| Basilica Management Limited | Real estate | 2005 |
| Basilico Leeds Ltd | Hospitality | 2025 |
| Basis Consulting Limited | Extraterritorial | 2002 |
| Basis Solutions Limited | Extraterritorial | 2002 |
| Basis Yorkshire Ltd | Health & social care | 2007 |
| Basit Kamboh Ltd | Wholesale & retail | 2025 |
| Baskind Gastro Limited | Health & social care | 2023 |
| Baskind Health Limited | Health & social care | 2017 |
| Basmed Ltd | Wholesale & retail | 2023 |
| Bass MED Ltd | Health & social care | 2018 |
| Bassface Promotions UK Ltd | Administrative & support | 2017 |
| Bassilious Associates Ltd. | Administrative & support | 2016 |
| Basstadka Limited | Hospitality | 2025 |
| Bassured Law Limited | Professional & scientific | 2012 |
| Basum Zest Limited | Wholesale & retail | 2024 |
| Batchd Limited | Hospitality | 2022 |
| Batchstamp Limited | Households | 1986 |
| Bate Soila Ltd | Health & social care | 2019 |
| Bates Family Investments Limited | Financial services | 2017 |
| Bateson Limited | Construction | 2002 |
| Bateson Property Limited | Real estate | 2023 |
| Bath Lane Mills Freehold Ltd | Real estate | 2026 |
| Bathurst Partners Ltd | Professional & scientific | 2015 |
| Batistas Boilers and Utilities Ltd | Construction | 2025 |
| Batley Gelato Ltd | Hospitality | 2021 |
| Batli Prime Ltd | Wholesale & retail | 2026 |
| Batt-Capelli Limited | Extraterritorial | 2020 |
| Battery Arbitrage Capital Limited | Construction | 2025 |
| Battery Capital Limited | Construction | 2025 |
| Batty France Ltd | Construction | 2020 |
| Batty Moss Limited | Hospitality | 2004 |
| Bauer CX Consulting Ltd | Professional & scientific | 2026 |
| Bauer Financial Ltd | Real estate | 2015 |
| Bauman Lyons Architects Limited | Professional & scientific | 1997 |
| Baumann Media Ltd | Information & communication | 2016 |
| BAV Property Investments Ltd | Real estate | 2018 |
| Bavaria Automotive Ltd | Wholesale & retail | 2019 |
| Bavette Bistro Ltd | Hospitality | 2023 |
| BAW Surveying Ltd | Professional & scientific | 2025 |
| Bawa MED Limited | Health & social care | 2020 |
| Bawtry Limited | Real estate | 2022 |
| BAX Property Ltd | Real estate | 2023 |
| Baxmed Regulatory Ltd | Professional & scientific | 2023 |
| Baxter Holiday Lettings Limited | Hospitality | 2026 |
| Baxter Marketing Co. Ltd | Professional & scientific | 2025 |
| Baxter Property Investment Limited | Real estate | 2007 |
| Baxter Real Estate Limited | Real estate | 2015 |
| Bay Communications Ltd | Professional & scientific | 2021 |
| Bay Laurel Hair Limited | Other services | 2023 |
| Bay Sentry Limited | Information & communication | 2015 |
| Bay&Co. Trading Limited | Wholesale & retail | 2016 |
| Baya Maintenance Ltd | Construction | 2020 |
| Baybridge Executive Search Partners Limited | Administrative & support | 2021 |
| Baydale Limited | Professional & scientific | 2015 |
| Baynian Ltd | Administrative & support | 2018 |
| Bayside Consulting Ltd | Administrative & support | 2024 |
| Bayside Property Solutions Limited | Households | 2026 |
| Bayswater Attorneys Limited | Professional & scientific | 2009 |
| Bayswater Bank Limited | Financial services | 2006 |
| Bayswater Computer Systems Limited | Other services | 2003 |
| Bayswater Consultancy Ltd | Administrative & support | 2025 |
| Bayswater Group Limited | Professional & scientific | 1999 |
| Bayswater Hotels Group Ltd | Hospitality | 2009 |
| Bayswater Hotels Limited | Hospitality | 2000 |
| Bayswater Properties (UK) Limited | Real estate | 1995 |
| Bayswater Residential & Nursing Homes Limited | Health & social care | 2000 |
| Bayswater Stores Limited | Wholesale & retail | 1999 |
| Bayswater Traders Ltd | Administrative & support | 2025 |
| Bayswater Transport Limited | Transport & logistics | 2001 |
| Bayswater Wholesale Limited | Wholesale & retail | 1995 |
| Baytul Istithmar Ltd | Real estate | 2026 |
| BAZ Barber Eastbourne Ltd | Other services | 2022 |
| BAZ Distribution Limited | Wholesale & retail | 2021 |
| Bazaar Catering Limited | Hospitality | 2019 |
| Bazaar Studio Holdings Limited | Financial services | 2026 |
| Bazaar Studio Limited | Arts & recreation | 2016 |
| Bazaar Studio Storage Ltd | Transport & logistics | 2024 |
| BB Camera Services Ltd | Information & communication | 2013 |
| BB North Limited | Real estate | 2023 |
| BB Properties (Yorkshire) Ltd | Real estate | 2022 |
| BB Talent Resourcing Ltd | Administrative & support | 2025 |
| BB Trustees 1 Limited | Professional & scientific | 2021 |
| BB Trustees 2 Limited | Professional & scientific | 2021 |
| BBB Takeouts Ltd | Hospitality | 2019 |
| BBC Developments Limited | Real estate | 1999 |
| BBE NJS Care Limited | Public administration | 2025 |