| BAE Reformer Ltd | Arts & recreation | 2026 |
| Bafole Ltd | Real estate | 2020 |
| Bahee Limited | Professional & scientific | 2013 |
| Baibeauty Limited | Wholesale & retail | 2026 |
| Baileys Property Solutions Ltd | Construction | 2021 |
| Baillie Chartres Limited | Professional & scientific | 2008 |
| Baillie Ritchie Consulting Ltd | Professional & scientific | 2020 |
| Baisu Limited | Construction | 2012 |
| Baker & Brown LP | | 2019 |
| Bakers Field (Rainham) Management Company Ltd | Households | 2017 |
| Bakker Chiropractic Limited | Health & social care | 2014 |
| Balancia Accountancy Limited | Professional & scientific | 2025 |
| Balbeggie Solar Limited | Construction | 2020 |
| Balci Properties Ltd | Real estate | 2023 |
| Baldry Investments Ltd | Real estate | 2024 |
| Bales&Tails Ltd | Other services | 2024 |
| Balmoral Storage Company Limited | Transport & logistics | 2012 |
| BAM Property Development Limited | Real estate | 2015 |
| Banana Boat Creative Ltd | Information & communication | 2021 |
| Banjo Services (UK) Ltd | Construction | 2013 |
| Banks & Partners Limited | Professional & scientific | 2015 |
| Banonbury Developments Limited | | 1984 |
| Barbell Lounge Ltd | Arts & recreation | 2022 |
| Barbu Building Limited | Construction | 2025 |
| Barbun Limited | Hospitality | 2019 |
| Barca Seventy Limited | Real estate | 2024 |
| Barcham Green Management Company Limited | Households | 2010 |
| Barclay Commercial Estates Limited | Real estate | 2014 |
| Barclay Commercial Investments Limited | Real estate | 2012 |
| Barclay Estates Limited | Real estate | 1998 |
| Barclay Group Limited | Extraterritorial | 2000 |
| Barclay Home Investments Limited | Real estate | 1999 |
| Barclay Property Centre Ltd | Real estate | 2022 |
| Barclay Property Trading LLP | | 2005 |
| Bare Necessities Limited | Wholesale & retail | 1994 |
| Barema | Other services | 1976 |
| Baresip Ltd | Wholesale & retail | 2026 |
| Barham Court (Management) Limited | Households | 1986 |
| Barham Lodge Management Company Ltd | Households | 2020 |
| Barilone Properties Limited | Real estate | 1960 |
| Baristo Ltd | Hospitality | 2022 |
| Bark Hart Limited | Professional & scientific | 2020 |
| Barkerollins Ltd | Administrative & support | 2012 |
| Barky Barbers Ltd | Other services | 2024 |
| Barley Construction Limited | Extraterritorial | 2009 |
| Barley Construction Management Limited | Extraterritorial | 2001 |
| Barley Project Management Ltd | Construction | 2022 |
| Barllows Services Ltd | Hospitality | 2018 |
| Barnabas RTM Company Limited | Real estate | 2023 |
| Barnsley and Strutmond Ltd | Real estate | 2025 |
| Barons Group Limited | Construction | 2012 |
| Barrbatt Services Ltd | Construction | 2018 |
| Barrett Commercial Limited | Administrative & support | 2024 |
| Barry Moen Editor Ltd | Information & communication | 2026 |
| Barta Limited | Other services | 2005 |
| Bartha Contemporary Limited | Wholesale & retail | 2011 |
| Barts Thoracic Surgery Education and Research Group Ltd | Professional & scientific | 2026 |
| BAS Consulting Group Ltd | Professional & scientific | 2026 |
| BAS Music Limited | Arts & recreation | 2010 |
| Basars Maritime Ltd | Extraterritorial | 2026 |
| Basasar Limited | Extraterritorial | 2023 |
| Bason Holdings Ltd | Financial services | 2020 |
| Bassiton Leasing Limited | Real estate | 2015 |
| Baston Manor Residents Company Limited | Real estate | 2000 |
| Batash Limited | Agriculture & fishing | 2024 |
| Batslamuk Limited | Arts & recreation | 2025 |
| Batur Consulting Limited | Professional & scientific | 2025 |
| Batur Holdings Limited | Financial services | 2025 |
| Baxter Philips Limited | Real estate | 1990 |
| Bay Window Creative Limited | Information & communication | 2017 |
| Baytree Property Services Limited | Administrative & support | 2015 |
| BB DEV Ltd | Information & communication | 2022 |
| BBB Property Ltd | Real estate | 2018 |
| Bbdb Limited | Arts & recreation | 2024 |
| Bbstem Limited | Professional & scientific | 2017 |
| BC Traders Limited | Hospitality | 2018 |
| BCA Performance Ltd | Arts & recreation | 2023 |
| BCC Trading Limited | Education | 2020 |
| Bccf Electrical Ltd | Construction | 2016 |
| BCR Publishing Ltd. | Information & communication | 1998 |
| BD Carpentry & Builders Ltd | Manufacturing | 2023 |
| BD Consult Limited | Professional & scientific | 2007 |
| BD Interiors Ltd | Professional & scientific | 2023 |
| BD Projects Ltd | Professional & scientific | 2024 |
| BDG Delivery UK Ltd | Transport & logistics | 2025 |
| BDK Accountants Ltd | Professional & scientific | 2013 |
| BDK Capital Limited | Real estate | 2017 |
| BDK Limited | Professional & scientific | 2023 |
| BDK Partners Ltd | Financial services | 2011 |
| BDR Digital Ventures Ltd | Wholesale & retail | 2021 |
| Bdrywall Solution Ltd | Construction | 2023 |
| BE Fabulous Boutique Limited | Other services | 2012 |
| BE U Ltd | Wholesale & retail | 2025 |
| Beach FX Limited | Administrative & support | 2023 |
| Beacon Management INT Ltd | Real estate | 2025 |
| Beacon Staffing Management Limited | Professional & scientific | 2025 |
| Beale Ironmongers Limited | Wholesale & retail | 2024 |
| Bean Works Ltd | Arts & recreation | 2013 |
| Bear Florian Limited | Wholesale & retail | 2022 |
| Bears Prestige Limited | Transport & logistics | 2025 |