| Altivest Holding Ltd | London | 2026 |
| Altivor Group Limited | London | 2026 |
| Altkuz Capgain Global Ltd | Glasgow | 2024 |
| Altman Finance Investment Co., Ltd | Somerset | 2021 |
| Altman Property Holdings Limited | Watford | 2025 |
| Altnagra Investments Limited | Chester | 2018 |
| Altnaharrie Holdings Ltd | Wadebridge | 2016 |
| Altnet Partners Holdco Limited | London | 2024 |
| Altnet Partners Limited | London | 2024 |
| Alto 5 Limited | Worcester | 2018 |
| Alto Financial Technologies Ltd | London | 2025 |
| Alto Global Partners Ltd | Beckenham | 2026 |
| Alto Insurance Group Ltd | Retford | 2012 |
| Alto Integra Wealth Management Limited | Romsey | 2025 |
| Alto J Limited | Eastwood | 2024 |
| Alto Malema HPP Limited | London | 2024 |
| Alto QS Limited | Chelmsford | 2016 |
| Alto Underwriting Limited | London | 1998 |
| Alto Verde Holdings Limited | Leicester | 2019 |
| Altoba Holdings Ltd | Daventry | 2025 |
| Altoft Holdings Ltd | Axminster | 2023 |
| Altogether Care (Holdings) Ltd | Dorchester | 2024 |
| Altogether Financial Solutions Limited | Baildon | 2008 |
| Altola Limited | Bournemouth | 2025 |
| Altolive UK Ltd | London | 2025 |
| Altomed Group Holdings Limited | Toddington | 2026 |
| Altomo Ltd | Harrow | 2017 |
| Alton Bidco Limited | Bristol | 2025 |
| Alton Capital Group Limited | Bournemouth | 2023 |
| Alton Care Group Limited | Harrow | 2009 |
| Alton Cars Holdings Limited | Leeds | 2021 |
| Alton Court Group Ltd | Leominster | 2024 |
| Alton Holdco Limited | Bristol | 2025 |
| Alton Limited | London | 2016 |
| Alton Mortgages Limited | Berkshire | 2005 |
| Alton Property Sales Ltd | Hartlepool | 2019 |
| Alton Wealth Management Limited | Bristol | 2017 |
| Altonotion Holdings Ltd | London | 2016 |
| Altoona Securities Limited | Portsmouth | 1996 |
| Altor Group Ltd | Richmond | 2026 |
| Altor RE Ltd | London | 2024 |
| Altorfer Financial Management Limited | Waltham Cross | 1990 |
| Altoria Group Ltd | Newcastle Upon Tyne | 2017 |
| Altostratus Holdings Limited | London | 2024 |
| Altoviti Limited | 15 Forlease Road | 2017 |
| Altpaynet Global Holdings, Ltd. | London | 2024 |
| Altra Energy Holding Limited | St. Albans | 2020 |
| Altra Holdings Group Ltd | Birmingham | 2025 |
| Altracap Holdings Ltd | London | 2025 |
| Altraise Advisory UK Limited | London | 2014 |
| Altrasta Capital Limited | Woodford Green | 2017 |
| Altree Capital (UK) Ltd. | London | 1999 |
| Altrevgen Ltd | West Byfleet | 2023 |
| Altrincham Home Limited | Altrincham | 2019 |
| Altrincham Treasure Limited | Altrincham | 2026 |
| Altrio Holdings Ltd | Blackburn | 2025 |
| Altrium Financial Services Ltd | London | 2024 |
| Altro Enterprises Ltd | Windsor | 2021 |
| Altrsol Ltd | Kington | 2024 |
| Altru Group Ltd | Droitwich | 2026 |
| Alts Ventures Ltd | London | 2025 |
| Altshare Holdings Limited | London | 2022 |
| Altum Depositary (UK) Limited | London | 2024 |
| Altum Fund Services (UK) Limited | London | 2024 |
| Altum Holdings (UK) Limited | London | 2018 |
| Altun Finance Limited | Waltham Cross | 2006 |
| Altunatmaz Jewellery Limited | Waterlooville | 2025 |
| Altungok Trading Ltd | Kington | 2025 |
| Altura Capital Partners Limited | London | 2025 |
| Altura Energy Group Holdings Ltd | Rochdale | 2025 |
| Altura Group Holdings Ltd | Ware | 2025 |
| Altura Holdings Group Ltd | Preston | 2025 |
| Altura Holdings Ltd | London | 2024 |
| Altura Innovations Ltd | Birmingham | 2025 |
| Altura Mortgage Finance Limited | London | 2018 |
| Altura Property Holdings Limited | London | 2025 |
| Altura Specialist Finance Limited | London | 2023 |
| Altura Ventures Limited | London | 2023 |
| Alturex Capital Limited | Waterlooville | 2025 |
| Alturos Group Limited | Hyde | 2025 |
| Altus Accounting and Bookkeeping Limited | Reigate | 2025 |
| Altus Holdings Limited | Upper Boat | 2026 |
| Altus IM Nominees Limited | London | 2021 |
| Altus Investment Management Limited | London | 2003 |
| Altus Nominees Limited | London | 2017 |
| Altus Risk Partners Ltd | London | 2025 |
| Altus Technical Group Ltd | Neston | 2018 |
| Altus UW Limited | London | 2020 |
| Altus Ventures Group Limited | Guildford | 2023 |
| Altvestor Ltd | London | 2025 |
| Altyx Corporate Limited | London | 2024 |
| Altyx Financial Planning Ltd | London | 2009 |
| ALU Group U.K. Ltd | London | 2023 |
| Alubar Global Holding Limited | London | 2025 |
| Alucare Industry (Holding) Ltd | London | 2022 |
| Alucia Ltd | Brighton | 2025 |
| Aluco Limited | Huntingdon | 2017 |
| Aluline Group Limited | Runcorn | 2010 |
| Aluma Capital Holdings Limited | London | 2021 |
| Alumet Holdings Limited | Southam | 2020 |