| Bartlett & Company Limited | Leeds | 1940 |
| Bartlett & Jones Limited | Port Talbot | 2018 |
| Bartlett Automotive Holdings Limited | Huntingdon | 2017 |
| Bartlett Group Limited | Leeds | 1969 |
| Bartlett International Holdings Limited | Airdrie | 2009 |
| Bartlett Investments Limited | Poole | 2025 |
| Bartlett James Risk Solutions Limited | Ashby-De-La-Zouch | 2018 |
| Bartlett Miller Limited | Farnham | 2006 |
| Bartlett Trustee Limited | Leeds | 2003 |
| Bartlett Underwriting Limited | Leeds | 2025 |
| Bartlett Wealth Management Ltd | Leeds | 1965 |
| Bartley Capital Group Ltd | Leeds | 2026 |
| Bartley Power Limited | London | 2014 |
| Bartley Way Holdings Limited | London | 2016 |
| Barton Bridging Capital Limited | London | 2008 |
| Barton Brown Limited | London | 2006 |
| Barton Capital Limited | Letchworth Garden City | 2024 |
| Barton Farms Holdings Limited | Retford | 2023 |
| Barton Fields Holdings Limited | Burton On Trent | 2024 |
| Barton Financial Limited | Leicester | 2015 |
| Barton Firtop Holdings (UK) Limited | Kidderminster | 2021 |
| Barton Grange Holdings Limited | Preston | 2025 |
| Barton Group Holding Ltd | Bilston | 2021 |
| Barton Holdings (2025) Ltd | Bedford | 2025 |
| Barton Inc Ltd | Newport | 2026 |
| Barton Knight Group Ltd | Guildford | 2022 |
| Barton Lily | Cambridge | 2023 |
| Barton Lyle Limited | London | 1990 |
| Barton Phillips Limited | Wigton | 2012 |
| Barton Point Limited | Wigan | 2025 |
| Barton Real Estate Holdings Limited | Wimborne | 2026 |
| Barton Ridge Holdings Ltd | Nr Chester | 2018 |
| Barton Road Capital Limited | London | 2023 |
| Barton Willow Ltd | Banbury | 2024 |
| Bartons Mead Group Ltd | Croydon | 2022 |
| Bartonwood Leasing Limited | Dartmouth | 2014 |
| Bartram Holdings Limited | Norwich | 2021 |
| Bartreyee Property Limited | Matlock | 2022 |
| Barts Insurance Brokers Limited | London | 1979 |
| Baruch Capital Limited | London | 2021 |
| Baruch H Ltd | Middleton | 2022 |
| Baruk Capital Partners Limited | London | 2014 |
| Barvae Group Limited | Beverley | 2018 |
| Barvae Holdings Limited | Beverley | 2011 |
| Barvani Limited | Poulton-Le-Fylde | 2026 |
| Barvio Limited | Kington | 2025 |
| Barwell PLC | Glasgow | 1993 |
| Barwells Wealth Limited | Lewes | 2026 |
| Barwick Dental Laboratory Services Limited | Middlesbrough | 2002 |
| Barwick Electrical Holdings Limited | Leeds | 2019 |
| Barwick Green Investments Limited | Tipton | 2023 |
| Barwick Holdings (Leeds) Limited | Leeds | 2024 |
| Barwick House Holdings Ltd | Chester | 2025 |
| Barwick Ventures Limited | Bradford | 2017 |
| Barwin EOT Limited | Goodmayes | 2025 |
| Barwise Commercial Ltd | Wrexham | 2023 |
| Barwise Contracting Services Limited | Liverpool | 2014 |
| Barwise Holdings Limited | Llay | 2013 |
| Barwood Capital (CPF2017) Limited | Towcester | 2017 |
| Barwood Capital (RIPDM1) Limited | Towcester | 2018 |
| Barwood Capital (RIPDM2) Limited | Towcester | 2018 |
| Barwood Capital Holdings Limited | Towcester | 2012 |
| Barwood Capital Limited | Towcester | 2009 |
| Barwood General Partner 2017 (Nominee) Limited | Towcester | 2017 |
| Barwood General Partner Growth Fund (IV) Limited | Towcester | 2019 |
| Barwood General Partner Growth Fund (V) Limited | Towcester | 2022 |
| Barwood Holdings Limited | Towcester | 2023 |
| Barwood Regional Property Growth Fund V (Founder Partner GP) Limited | Edinburgh | 2022 |
| Barwood Ventures Holdings Limited | London | 2013 |
| Barxton Limited | Glasgow | 2023 |
| Barxwise Ltd | Penryn | 2023 |
| Baryah Properties Holdings Limited | Bristol | 2023 |
| Baryon Holdings Limited | Slough | 2021 |
| Barzel Estates Holdings Limited | London | 2025 |
| BAS 1 Group Ltd | Rainham | 2024 |
| BAS 4 U Ltd | Preston | 2021 |
| BAS Ayin Ltd | London | 2024 |
| BAS Group Holdings Limited | Southampton | 2025 |
| BAS Venture Capital Ltd | Harrow | 2024 |
| Basa Investment Agent Ltd | London | 2024 |
| Basalt Group Limited | Antrim | 2021 |
| Basama Consumer NO.1 Ltd | London | 2024 |
| Basama Consumer NO.2 Ltd | London | 2025 |
| Basandrai Group Ltd | Trowbridge | 2021 |
| Basant & Sons Ltd | Hayes | 2017 |
| Basar Holdings Limited | Morden | 2024 |
| Basarabia Group Ltd | Cardiff | 2019 |
| Basb Limited | Stanmore | 2012 |
| Bascom Financial Services Limited | Liverpool | 2013 |
| Bascombe Holdings Limited | Wimborne | 2022 |
| Bascs Group Limited | Rawtenstall | 2024 |
| Bascule Settlements Limited | Neath | 2025 |
| Base Build Services Holdings Limited | London | 2014 |
| Base Camp Holdings Limited | Dundee | 2015 |
| Base Club Holding Ltd | Hinckley | 2026 |
| Base Contracts Holdings Limited | London | 2021 |
| Base Financial Limited | Tonbridge | 2015 |
| Base Holdings (London) Limited | London | 2019 |
| Base Holdings Limited | Liverpool | 2024 |
| Base INS Brokers Ltd | Worthing | 2021 |