| Ayla KAI Limited | Real estate | 2022 |
| Ayngaran Business Intelligence Ltd | Information & communication | 2014 |
| Ayvazov Ltd | Construction | 2016 |
| AZ Financial Consulting Limited | Administrative & support | 2012 |
| AZ London Property Management Limited | Households | 2018 |
| AZI Health Limited | Health & social care | 2021 |
| Azlinc Group Ltd | Wholesale & retail | 2025 |
| B & B Property Development Limited | Construction | 2005 |
| B & K (London) Property Ltd | Real estate | 2020 |
| B a B Investments Ltd | Real estate | 2023 |
| B Away on Holiday Ltd. | Administrative & support | 2007 |
| B HOY Limited | Professional & scientific | 2011 |
| B London Agency Limited | Administrative & support | 2017 |
| B&H Ambassador's Hatch END Ltd | Other services | 2018 |
| B&H Ambassador's Pinner Ltd | Other services | 2018 |
| B&J Freeholds Ltd | Real estate | 2016 |
| B&N Air Conditioning Ltd | Energy | 2023 |
| B&N Empathy Ltd | Real estate | 2023 |
| B.B.S. Autos Limited | Wholesale & retail | 2009 |
| B.K. Kandola Limited | Wholesale & retail | 2002 |
| B.L.A.C.K. PTY Limited | Professional & scientific | 2011 |
| B.S. Sports Limited | Wholesale & retail | 1987 |
| B3YGO Limited | Professional & scientific | 2023 |
| Baako Consulting Limited | Professional & scientific | 2016 |
| Baba Wali Restaurant Ltd | Hospitality | 2018 |
| Baby M Ltd | Extraterritorial | 2017 |
| Baby Melody London Limited | Wholesale & retail | 2024 |
| Babyballers Finchley Ltd | Health & social care | 2025 |
| Bacchus Estates Limited | Real estate | 2002 |
| Back to New (2016) Limited | Wholesale & retail | 2016 |
| Backhouse Property Services Ltd | Real estate | 1981 |
| Baelling Limited | Information & communication | 2007 |
| Bags Consulting Limited | Real estate | 2015 |
| Bahi Real Estate Ltd | Real estate | 2020 |
| Bailey Bhardwaj Investments Limited | Real estate | 2017 |
| Baileys Marvel Ltd | Information & communication | 2019 |
| Bakir GAS Limited | Construction | 2022 |
| Balaji Birmingham Ltd | Financial services | 2025 |
| Balaji Dental Limited | Health & social care | 2014 |
| Balaji Growth Limited | Information & communication | 2024 |
| Balaji Investment Ltd | Health & social care | 2023 |
| Balaji Property Limited | Real estate | 2020 |
| Balancing Bear Limited | Professional & scientific | 2022 |
| Balchem Limited | Other services | 2007 |
| Balendra Assets Ltd | Real estate | 2021 |
| Balendra Estates Limited | Real estate | 2017 |
| Ballo Industries Ltd | Information & communication | 2024 |
| Balloon 421 Limited | | 1978 |
| Balloon Decor & Events Limited | Wholesale & retail | 2019 |
| Balmain Point Ltd | Health & social care | 2023 |
| Bambhra Properties Limited | Real estate | 2021 |
| BANAS44 Ltd | Information & communication | 2018 |
| Banith Group Consortium Limited | Information & communication | 2012 |
| Banway Realty Limited | Real estate | 2022 |
| Banyan Tree Architects Ltd | Professional & scientific | 2021 |
| Baobab Property Investments Limited | Real estate | 2020 |
| Bapd Limited | Other services | 2018 |
| Barber EVO Ltd | Other services | 2026 |
| Bargain Booze Ltd | Wholesale & retail | 2023 |
| Barhale Engineering Limited | Construction | 2020 |
| Barking Goose Ltd | Other services | 2026 |
| Barnet Combat Academy Ltd | Arts & recreation | 2020 |
| Barnhill Services Limited | Professional & scientific | 2020 |
| Barntown Ltd | Other services | 2015 |
| Baron Holyport NO2 Limited | Real estate | 2024 |
| Baron Rainville Limited | Real estate | 2024 |
| Barrie Johnston Coaching Limited | Other services | 2025 |
| Barrington Management Solutions Limited | Administrative & support | 2022 |
| Barry Hammond Ltd | Real estate | 2010 |
| Barton Tyndall Limited | Real estate | 2020 |
| Bartrams Holdings Ltd | Other services | 2020 |
| Bartrams Property Consultants Limited | Real estate | 2001 |
| Barulis Limited | Arts & recreation | 2007 |
| Bass Centre Limited(The) | Wholesale & retail | 1983 |
| Bassarabica Limited | Other services | 2013 |
| Batchbuild Investments Ltd | Professional & scientific | 2017 |
| Bateman Building Company Limited | Construction | 1932 |
| Bath Hospitality Limited | Hospitality | 2016 |
| Bathexpert Ltd | Construction | 2009 |
| Batman Properties Limited | Real estate | 2023 |
| Battersea Hardware Ltd | Wholesale & retail | 2025 |
| Baum Vision Europe Limited | Wholesale & retail | 2002 |
| Baxle Ltd | Transport & logistics | 2011 |
| Baxle Projects Limited | Administrative & support | 2026 |
| Bay Health Ltd | Real estate | 2024 |
| Bay Osteopath Ltd | Health & social care | 2011 |
| Baycona Limited | Wholesale & retail | 2006 |
| Bazar Live International Ltd | Wholesale & retail | 2018 |
| Bazar London Ltd | Hospitality | 2016 |
| BB AUM 2 Limited | Real estate | 2021 |
| BB Football Limited | Arts & recreation | 2023 |
| BBA Care Limited | Hospitality | 2015 |
| Bbtd Creative Limited | Professional & scientific | 2025 |
| Bcall Limited | Professional & scientific | 2023 |
| Bcrystal.Art Ltd | Manufacturing | 2025 |
| BDV Realtor Limited | Construction | 2019 |
| BDV Trading Limited | Real estate | 2017 |
| BE Thoughtfull Limited | Professional & scientific | 2025 |
| Beach Huts Bexhill Ltd | Real estate | 2024 |
| Beacon Court (Highcliffe) Limited | Households | 1986 |