| Astute Wealth Management Ltd | Malvern | 2008 |
| Astute Wealth Planning Limited | Hurstpierpoint | 2012 |
| Astute Wealth Services Ltd | Ewloe | 2019 |
| Astutus Finance Limited | Heathfield | 2020 |
| Astwood (Property) Holdings Limited | Stoke-On-Trent | 2026 |
| Astwood (Trade) Holdings Limited | Stoke-On-Trent | 2026 |
| Astwood Equities Limited | Bromsgrove | 2011 |
| Astwood Group Ltd | Cranleigh | 2019 |
| Astwood Holdings Limited | Bromsgrove | 2019 |
| ASU Ventures Ltd | Cardiff | 2024 |
| Asumah Holding Group Ltd | Wembley | 2025 |
| Asunta Holdings UK Limited | Bath | 2025 |
| Asura Financial Holdings Limited | London | 2026 |
| Asura Financial Ltd | Newtownabbey | 2007 |
| Asure Financial Limited | Consett | 2018 |
| Asurelife Ltd | Preston | 2024 |
| Asurion Europe Limited | Middlesex | 2008 |
| ASV Consultants Limited | Leatherhead | 2025 |
| Asvsh Accountancy Services Limited | London | 2004 |
| ASW Associates Limited | Sittingbourne, Kent | 2019 |
| ASW Financial Management Ltd | Sutton Coldfield | 2016 |
| ASW Holdings Limited | Manchester | 2024 |
| Aswa Holdings Ltd | London | 2020 |
| Aswani Holdings Limited | Birmingham | 2023 |
| Aswatrealestate Ltd | London | 2025 |
| Aswbuilding Ltd | Cirencester | 2025 |
| ASX International Ltd | Holmfirth | 2022 |
| Asymmetric Group Ltd | Dartmouth | 2025 |
| Asymmetric Holdings Ltd | Exeter | 2024 |
| Asymmetrix Partners Limited | Altrincham | 2024 |
| Asymmetry Capital Ltd | Cardiff | 2025 |
| Asyst Group Limited | Reigate | 2004 |
| Asyst Holdings Limited | Reigate | 2007 |
| Asyst UK Bidco Limited | Loughborough | 2022 |
| Asyst UK Midco Limited | Loughborough | 2022 |
| Asyst UK Topco Limited | Loughborough | 2022 |
| AT & MA Holdings Limited | Wadhurst | 2023 |
| AT & MB Investments Ltd | Tyne & Wear | 2025 |
| AT & NC Property Limited | Glasgow | 2026 |
| AT & P (Topco) Ltd | Guisborough | 2025 |
| AT & SA Holdings Ltd | Wilmslow | 2025 |
| AT & T Pension Scheme Trustee Limited | Studley | 1999 |
| AT & TF Holdings Limited | Warwick | 2021 |
| AT 8 Ltd | Hereford | 2018 |
| AT Asset Finance Ltd | Cheltenham | 2022 |
| AT Brady Bidco Limited | London | 2017 |
| AT Brady Holdings Limited | London | 2017 |
| AT Centaur's Ltd | Harrow | 2020 |
| AT Chesson Ltd | Leatherhead | 2026 |
| AT Echo Limited | London | 2014 |
| AT FIC Subsidiary Limited | London | 2025 |
| AT Financial Solutions Limited | Southampton | 2013 |
| AT Football International Investment Limited | London | 2025 |
| AT Gill Enterprises Investments Ltd | Milton Keynes | 2024 |
| AT Global Holdings Limited | Witney | 2019 |
| AT Global Markets (UK) Limited | London | 2015 |
| AT Gostenski Group Ltd | Bury St. Edmunds | 2025 |
| AT Group Investments Limited | Maidstone | 2023 |
| AT Holdings (NW) Ltd | Altrincham | 2016 |
| AT Home Mortgages Limited | Durham | 2014 |
| AT Homecare Holdings Limited | Doncaster | 2022 |
| AT Intermediary Services Ltd | Bishopton | 2026 |
| AT Management Consultancy Limited | Durham | 2020 |
| AT Mortgage Consultants Ltd | Portsmouth | 2021 |
| AT Mortgages Ltd | Haverfordwest | 2020 |
| AT NO.1 Limited | Cambridge | 2021 |
| AT P.I Solutions Ltd | Glasgow | 2023 |
| AT Pace Mortgages Limited | Southsea | 2018 |
| AT Park Street Ltd | Lytham St. Annes | 2025 |
| AT Properties (South West) Limited | Warminster | 2023 |
| AT Property Holdings Limited | Exeter | 2017 |
| AT Reef Ltd | Stockport | 2025 |
| AT Retirement Options Wealth Management Ltd | Warrington | 2013 |
| AT Retirement Services Ltd | Lymington | 2013 |
| AT Sea Holdings Ltd | Cobham | 2026 |
| AT Squared Holdings Limited | London | 2019 |
| AT UK Holdings Limited | Birmingham | 2026 |
| AT Venture Studios Limited | London | 2023 |
| AT World Ltd | London | 2025 |
| At&S Holdings Limited | Birmingham | 2022 |
| At&T Group (UAE) Ltd | Aylesbury | 2025 |
| At-Bay Group (UK) Limited | Salford | 2025 |
| At-Us Business Finance Limited | Lichfield | 2013 |
| AT1511 Ltd | London | 2025 |
| AT3AM Leisure Ltd | Glasgow | 2026 |
| ATA (UK) Limited | Romford | 2010 |
| ATA Global Services Limited | London | 2025 |
| Ataa Limited | Sevenoaks | 1997 |
| Ataam Ltd | Dagenham | 2026 |
| Atacama Investments Limited | Surbiton | 2025 |
| Atadura Limited | Great Yarmouth | 2011 |
| Atahoran Ltd | London | 2025 |
| Ataji Holdings Ltd | Sheffield | 2025 |
| Atakash Capital Management Ltd | London | 2015 |
| Atal Exchange Ltd | London | 2009 |
| Atal Group UK Limited | Tredegar | 2018 |
| Atal Holdings Ltd | Tredegar | 2025 |
| Atal-Y-Ddraig Ltd | St Asaph Business Park | 2025 |
| Atalanta Group Ltd | Birmingham | 2025 |
| Atalanta Management Limited | Diss | 2014 |