| Border to Coast Warwickshire GP Limited | Edinburgh | 2019 |
| Border to Coast West Sussex GP Limited | Edinburgh | 2026 |
| Border Travel Holdings Limited | Dumfries | 2025 |
| Borderland Holdings Limited | Southampton | 2021 |
| Borderless Collective Limited | London | 2025 |
| Borders Legal Holdings Ltd | Kelso | 2024 |
| Borders Risk Management Limited | Haddington | 2013 |
| Borders Security Services Limited Limited | Uxbridge | 2022 |
| Bordershore Ltd | Ashington | 2023 |
| Borderway Finance Limited | Carlisle | 1995 |
| Bordier & CIE (UK) PLC | London | 1981 |
| Bordier International Ltd. | London | 2000 |
| Bordila Holdings Ltd | Manchester | 2023 |
| Boreal Group Ltd | Southampton | 2026 |
| Boreal Industrial EU Holdco 5 Limited | London | 2023 |
| Boreal Industrial EU Holdco 6 Limited | London | 2023 |
| Boreas (Investment) Limited | Soho | 2013 |
| Boreas Holdco Limited | Soho | 2013 |
| Boreas Holdings Limited | Worcester | 2017 |
| Boreas Sailing Limited | London | 2021 |
| Bored Incorporations Ltd | Norwich | 2021 |
| Boreham Holdings Ltd | Fareham | 2026 |
| Boreham's Car Electrical Service Limited | Oxford | 1939 |
| Borehole Solutions Group Ltd | Birmingham | 2018 |
| Borelli Tea Holdings Limited | Greenhithe | 1976 |
| Borer Limited | London | 2012 |
| Bores UK Holding Limited | Walton-On-Thames | 2026 |
| Borfin Unlimited | Barnard Castle | 2020 |
| Borg & Overstrom Holding Limited | Norwich | 2026 |
| Borg Holdings Limited | Southampton | 2025 |
| Borg Investments Ltd | Alcester | 2022 |
| Borg Protection Ltd | Hoddesdon | 2024 |
| Borga Money Limited | London | 2022 |
| Borgonon & Co Ltd | Cranleigh | 2006 |
| Borgwarner Trustees Limited | Bradford | 1988 |
| Borhani Holding Limited | London | 2019 |
| Borina Ltd | London | 2025 |
| Boring Capital Ltd | London | 2022 |
| Boring Investment Company Ltd | Stanmore | 2019 |
| Boris Fletcher Limited | Newcastle Upon Tyne | 2022 |
| Boristan Limited | Swindon | 2025 |
| Boriste Ltd | Chelmsford | 2018 |
| Borj Avaran Limited | London | 2013 |
| Borkam Properties Ltd | London | 2022 |
| Borkett Industries Limited | Hockley | 2023 |
| Borland Group Ltd | Glasgow | 2026 |
| Borland Group Property Holdings Ltd | Glasgow | 2026 |
| Borland Insurance Ltd | Glasgow | 1995 |
| Borlase Smart John Wells Trust Ltd | St Ives | 2005 |
| Borley Brothers Holdings Limited | Waltham Abbey | 2020 |
| Borley Holdings Limited | Cardiff | 2020 |
| Bormes Limited | London | 2025 |
| Born Creative Holdings Limited | London | 2016 |
| Born Enterprises Limited | Manchester | 2025 |
| Born in Scotland Ltd | Jedburgh | 2020 |
| Born Investments Ltd | London | 2026 |
| Born Limitless Holdings Limited | Nottingham | 2022 |
| Born to Rebel Ventures Limited | London | 2021 |
| Borne Holdings Limited | Stourbridge | 2023 |
| Borneo Group Limited | Padiham | 2025 |
| Bornoriginal Group Ltd | Glasgow | 2018 |
| Boro Holdings Limited | Rochdale | 2024 |
| Boron Inns Ltd | Armagh | 2022 |
| Boropex Acquisition Limited | London | 1999 |
| Borough Bench Holdings Limited | Winchester | 2021 |
| Borough Commercial Ltd | London | 2018 |
| Borough Communications Services Limited | Edinburgh | 2021 |
| Borough Green Holdings Limited | Rochester | 2017 |
| Borough Junction (Freehold) Limited | London | 2015 |
| Borough Projects Ltd | Watford | 2005 |
| Borough Residential Holdings Ltd | London | 2020 |
| Boroughbridge Holdings Ltd | Boroughbridge | 2026 |
| Boroughbridge Insurance Brokers Limited | North Yorkshire | 2009 |
| Boroughs Holdings Limited | Shrewsbury | 2019 |
| Borr (UK) Holdings Limited | Westhill | 2019 |
| Borr Mexico Ventures Limited | Westhill | 2019 |
| Borras Group Holdings Limited | St. Albans | 2013 |
| Borrie-Bonell Investment Company,Limited | Hove | 1951 |
| Borrow (UK) Limited | Ilford | 2014 |
| Borrowdale Eight Ltd | Preston | 2016 |
| Borshch Holdings Limited | Birmingham | 2019 |
| Borson Limited | Manchester | 2018 |
| Borthwick Group Holding Limited | Ashton-Under-Lyne | 2026 |
| Boru Group (Midlands) Limited | Stafford | 2024 |
| BOS (Shared Appreciation Mortgages (Scotland) NO.3) Limited | Halifax | 1997 |
| BOS (Shared Appreciation Mortgages) NO. 1 PLC | Halifax | 1995 |
| BOS (Shared Appreciation Mortgages) NO. 2 PLC | Halifax | 1996 |
| BOS (Shared Appreciation Mortgages) NO. 3 PLC | Halifax | 1997 |
| BOS (Shared Appreciation Mortgages) NO. 4 PLC | Halifax | 1997 |
| BOS (Shared Appreciation Mortgages) NO. 5 PLC | Halifax | 1997 |
| BOS (Shared Appreciation Mortgages) NO. 6 PLC | Halifax | 1997 |
| BOS Celtic Limited | Norwich | 2026 |
| BOS Contracting Limited | Manchester | 2026 |
| BOS FX Limited | Chippenham | 2025 |
| BOS Group Ltd | Aberaeron | 2026 |
| BOS HQ Ltd | Peterborough | 2009 |
| BOS Personal Lending Limited | | 1997 |
| BOS Taurus Holdings Ltd | Elgin | 2024 |
| BOS Wealth Management Limited | London | 2015 |
| Bosano Consulting Limited | Bristol | 2017 |