| ANY Capital Investments Limited | Harrow | 2019 |
| ANY Telecom Ltd | Waltham Cross | 2016 |
| Anyan Consulting Limited | Northwich | 2015 |
| Anyc Holdings Limited | Little Eaton | 2025 |
| Anycomp 2017 NO.2 Limited | Northampton | 2017 |
| Anyfunding Ltd | Hyde | 2011 |
| Anyma Capital Ltd | London | 2020 |
| Anything BUT Golf Ltd | Weybridge | 2020 |
| Anything Mortgage Limited | London | 2017 |
| Anytime Mortgages Ltd | Solihull | 2023 |
| Anytime Ventures Group Ltd | London | 2020 |
| Anyvan Finance Co Limited | London | 2020 |
| Anyvan Investment Holdings Limited | London | 2020 |
| Anyway Holdings Limited | Limavady | 2022 |
| Anyway Ventures Limited | York | 2025 |
| Anywhere Group Limited | Clitheroe | 2018 |
| ANZ & Co Group Limited | Dalmain Road | 2026 |
| ANZ Consulting Ltd | Birmingham | 2025 |
| ANZ Pensions (UK) Limited | London | 1951 |
| Anzar Ventures Ltd | London | 2025 |
| Anzen Wealth Consulting Ltd | Midhurst | 2023 |
| Anzille Ltd | London | 2024 |
| Anzl Limited | Harrow | 2017 |
| AO Capital Investments Ltd | Ellesmere Port | 2025 |
| AO Capital Partners Limited | London | 2024 |
| AO Group Ltd | Coventry | 2015 |
| AO Holdings Limited | West Sussex | 2017 |
| AO Home Group Limited | Luton | 2024 |
| AO Hotels Group Ltd | Edgware | 2024 |
| AO Ltd | Bolton | 2009 |
| AO Mortgages Limited | Gloucester | 2019 |
| AO3 Holdings Limited | Beaconsfield | 2017 |
| AO44 Holdings Limited | London | 2022 |
| AO44 Property Limited | London | 2022 |
| AOA Capital Holdings Limited | Chertsey | 2025 |
| AOC GP (UK) Ltd. | London | 2016 |
| AOD Investments Limited | Northwich | 2016 |
| Aodl Ltd | Plymouth | 2023 |
| Aoer Holdings Limited | Londonderry | 2025 |
| AOG Finance Limited | London | 2006 |
| AOG Investments Ltd. | London | 2012 |
| Aogro Holdings Ltd | Nottingham | 2020 |
| AOI Holdings Ltd | Bedfordshire | 2019 |
| AOJ Grazing Ltd | Aberaeron | 2024 |
| AOK Holdings Ltd | Glasgow | 2017 |
| AOK Property Ltd | Birmingham | 2021 |
| AOK Shareholdings Ltd | Liphook | 2026 |
| Aokar Holdings Ltd | London | 2023 |
| AOL Holdings Ltd | Stockport | 2024 |
| AOL Management Limited | Rayleigh | 2014 |
| AON ANZ Holdings Limited | London | 2012 |
| AON Canz UK Holdings Limited | London | 2026 |
| AON Capital Ltd | Bolton | 2022 |
| AON DC Trustee Limited | London | 2015 |
| AON Finance UK 1 Limited | London | 2019 |
| AON Finance UK 2 Limited | London | 2020 |
| AON Finance UK 3 Limited | London | 2020 |
| AON Finance UK 4 Limited | London | 2020 |
| AON Finance UK 5 Limited | London | 2022 |
| AON Global Holdings Intermediaries Limited | London | 1961 |
| AON Holdings Limited | London | 1988 |
| AON Life Solutions Limited | London | 2022 |
| AON Minet Pension Trustees Limited | London | 2021 |
| AON Overseas Holdings Limited | London | 2012 |
| AON Pension Trustees Limited | London | 1979 |
| AON Polar UK 1 Limited | London | 2023 |
| AON Polar UK 2 Limited | London | 2023 |
| AON Polar UK 3 Limited | London | 2024 |
| AON Randolph UK Limited | London | 2019 |
| AON Securities Limited | London | 1997 |
| AON UK Group Limited | London | 1989 |
| AON UK Holdings Intermediaries Limited | London | 2001 |
| AON UK Holdings Limited | London | 2008 |
| AON UK Limited | London | 1925 |
| AON US & International Holdings Limited | London | 2013 |
| Aonghusa Bunus Limited | Inverness | 2022 |
| Aonic UK Ltd | London | 2022 |
| Aonne Holdings Limited | Harlow | 2026 |
| Aontacht Holdings Limited | Stockport | 2025 |
| AOO Group Ltd | Liverpool | 2024 |
| Aooi Holding Ltd | Manchester | 2021 |
| Aoonea Ltd | Otley | 2026 |
| AOP GP Limited | London | 2017 |
| Aopia Limited | Edinburgh | 2025 |
| AOR Holdings Limited | Witney | 2019 |
| Aorp Investments Ltd | Sherborne | 2019 |
| AOS Air Conditioning and Engineering Holdings Limited | Birmingham | 2024 |
| Aosta Holdings Limited | Cardiff | 2024 |
| AOT Investments Ltd | Dartford | 2025 |
| Aotrom Limited | Lochgelly | 2019 |
| AOU Investments Limited | Maidenhead | 2024 |
| Aoye Group Holdings Limited | London | 2026 |
| Aozora Europe Limited | London | 2015 |
| AP & S Family Limited | Nr Warrington | 2024 |
| AP Adhesives Europe, Ltd | London | 2025 |
| AP Adviser Ltd | Stanmore | 2024 |
| AP Aguila Holdings, Ltd. | London | 2022 |
| AP Asset Holdings Ltd | Preston | 2023 |
| AP Baleine 3 Holdings Limited | Aberdeen | 2026 |
| AP Bashford Mortgages Ltd | Rotherham | 2024 |