| B.T.I.C. Limited | Dorking | 1996 |
| B.V.F. (Underwriting Management) Limited | Great Missenden | 1965 |
| B.W Quantum Ltd | Manchester | 2025 |
| B.W. Aylesbury (Holdings) Limited | Aylesbury | 2016 |
| B.W. Mortgages Limited | Midlothian | 2005 |
| B.W.A. (Commercial) Limited | Mappleborough Green | 1981 |
| B.W.J. Ltd | Wednesbury | 2021 |
| B.Y.E Enterprise UK Limited | London | 2024 |
| B10 Enterprise Ltd | Birmingham | 2022 |
| B10 Group Ltd | Cambridge | 2025 |
| B10 MED Properties Limited | York | 1996 |
| B1111 Holdings Ltd | Whatcote | 2017 |
| B18 Financial Group Limited | London | 2025 |
| B1K3 Ltd | Stourport-On-Severn | 2023 |
| B1ST Property Limited | Derby | 2025 |
| B2 Capital Management Holding Limited | London | 2024 |
| B2 Wealth Ltd | Spalding | 2012 |
| B2016 Ltd | Norwich | 2016 |
| B2A Investments Ltd | Burscough | 2023 |
| B2B Brokers Ltd | London | 2025 |
| B2B Cashflow Solutions Limited | Newcastle Upon Tyne | 2006 |
| B2B Effective Recoveral Limited | London | 2009 |
| B2B IT Services Holdings Limited | Cardiff | 2021 |
| B2B Loans & Mortgages Limited | Cardiff | 2006 |
| B2B Martech Group Ltd | London | 2024 |
| B2B1 Holdings Limited | Stockport | 2015 |
| B2BPOWER Ltd | London | 2026 |
| B2BUSINESS Corporate Consultants Ltd | London | 2021 |
| B2C (Holdings) Limited | Southend-On-Sea | 2010 |
| B2C Finance Ltd | Birmingham | 2009 |
| B2C2 Ltd | London | 2012 |
| B2FI Holding Ltd. | Worthing | 2024 |
| B2WISE Holdings Ltd | Leicester | 2024 |
| B3 Holdings Limited | Stoke-On-Trent | 2016 |
| B3 Homes Group Ltd | Chippenham | 2017 |
| B3 Insurance Limited | London | 2020 |
| B3 Management Limited | Leeds | 2013 |
| B3 S.A. - Brasil, Bolsa, Balcao UK Ltd | London | 2009 |
| B3 Wealth Management Limited | Dronfield | 2007 |
| B33 Group Limited | Winchester | 2024 |
| B3H Ltd | Sleaford | 2026 |
| B4 Group Limited | Salcombe | 2004 |
| B41LEY Holdings Limited | Keston | 2022 |
| B41LEY INV Limited | Kent | 2019 |
| B42 Investments | London | 2017 |
| B42.EA Limited | Park Farm Hotel, Norwich Road | 2020 |
| B4BS Investments Ltd | Hertford | 2016 |
| B4U Financial Services Limited | Paignton | 2015 |
| B4U Money Limited | Brierley Hill | 2021 |
| B51 Ventures Ltd | Newbury | 2021 |
| B5GDC Ltd | Glasgow | 2015 |
| B6 Camden Drive Ltd | Birmingham | 2025 |
| B6 Capital Partners Limited | Northampton | 2024 |
| B6 Corporate Solutions Ltd | London | 2023 |
| B6 Investments Ltd | London | 2022 |
| B7 151 Nominees Limited | Manchester | 2012 |
| B7 Care Group Ltd | Gateshead | 2022 |
| B7 Enterprises Limited | Maidenhead | 2002 |
| B88 Nexonet Trading Services Ltd | London | 2026 |
| B9 Holdings UK Limited | West Byfleet | 2026 |
| B97 Holding Limited | Doncaster | 2019 |
| B9H2 Ltd | Larne | 2020 |
| BA (GI) Limited | London | 1866 |
| BA Advisory and Partners Limited | Guildford | 2021 |
| BA Asset Management Ltd | Hove | 2020 |
| BA Enterprises Europe Ltd | Mitcham | 2001 |
| BA Exchange Company (UK) Limited | London | 2010 |
| BA Family Investment Company Limited | Stoke-On-Trent | 2024 |
| BA Finance International Ltd | London | 2016 |
| BA Financial Services Ltd | Leeds | 2020 |
| BA Gibbons Ltd | Birmingham | 2025 |
| BA Group (North East) Limited | Billingham | 2025 |
| BA Group Topco Limited | Wilmslow | 2025 |
| BA Healthcare Group Ltd | Huddersfield | 2023 |
| BA Holdco Limited | Harmondsworth | 2019 |
| BA Holdings and Investments Limited | Newport | 2021 |
| BA Latam PE Limited | London | 2011 |
| BA Mortgage Consultancy Services Ltd | Wisbech | 2023 |
| BA Mortgages & Protection Ltd | Sheringham | 2018 |
| BA Patel Limited | Edgware | 2015 |
| BA Space Between Ltd | Stockton On Tees | 2024 |
| Ba-Pan Ltd | Uckfield | 2021 |
| BA2 Holdings Limited | Clitheroe | 2024 |
| Baader Helvea Limited | | 2003 |
| Baahi Group Ltd | Cardiff | 2024 |
| Baanx.Com Ltd | Cambridge | 2018 |
| Baap Group Limited | Coventry | 2021 |
| Baat Limited | Folkestone | 2019 |
| Baaz & Co Holdings Ltd | Hounslow | 2026 |
| Baaz Investment Limited | Abertillery | 2024 |
| BAB Global Investment Limited | London | 2024 |
| BAB Global Limited | London | 2023 |
| BAB Group Holdings Limited | Bedford | 2025 |
| BAB Group Limited | London | 2022 |
| BAB International Holding Limited | London | 2024 |
| Baba JEE Holdings Ltd | Solihull | 2020 |
| Baba RE Ltd | Witham | 2017 |
| Babadil Limited | London | 2025 |
| Babahouse Ltd | Surbiton | 2025 |
| Babat Properties Ltd | Darlington | 2021 |