| Achernar Capital Limited | London | 2015 |
| Acheron Capital Limited | London | 2005 |
| Acheron Holding Ltd | London | 2023 |
| Achieve Education Limited | Cannock | 2014 |
| Achieve Financial Limited | Oldham | 2020 |
| Achieve Financial Planning Ltd | Inverness | 2009 |
| Achieve Health Holdings Ltd | London | 2022 |
| Achieve Holding Group Limited | Stafford | 2025 |
| Achieve Pension Consulting Ltd | Lytham St.Annes | 2018 |
| Achieve Wealth Management (Wiltshire) Limited | Swindon | 2014 |
| Achieve Your AIM (AYA) Ltd | London | 2024 |
| Achievement Holdings Limited | Norwich | 2026 |
| ACHIEVERS25 Community Interest Company | Manchester | 2026 |
| Achieving Higher Holdings Limited | Birmingham | 2020 |
| Achilles Consulting Ltd | London | 2017 |
| Achilles Estates Holdings Limited | Reigate | 2017 |
| Achilles Group Holdings Ltd | London | 2025 |
| Achilles Group Investments Limited | Abingdon | 2006 |
| Achilles Group Limited | Abingdon | 2000 |
| Achilles Holdco Limited | Abingdon | 2008 |
| Achilles Holdings Limited | Gillingham | 2020 |
| Achilles Medway (29) Limited | Gillingham | 2020 |
| Achilles Medway (32) Limited | Gillingham | 2020 |
| Achilles Partnership Ltd | Pevensey | 2020 |
| Achilles Therapeutics Holdings Limited | Birmingham | 2020 |
| Achirio Ltd | London | 2025 |
| Achnamara Holdings Limited | Lochgilphead | 2026 |
| Achorvic Hydro Limited | London | 2018 |
| Achour Investments Limited | Woodbridge | 2024 |
| Achp PLC | Chelmsford | 2001 |
| Acht&Acht Finance Limited | London | 2021 |
| ACI 2 Limited | London | 2022 |
| Acia Aero Capital (UK) Limited | Reading | 2017 |
| Acia Aero Leasing (UK) Limited | Reading | 2017 |
| Acib Holdings Limited | Nottingham | 2024 |
| Acid Labs Holdings Limited | London | 2022 |
| Acies (Cyber Hedge) Limited | London | 2021 |
| Acies Digital Limited | London | 2021 |
| Acies Holdings 1 Limited | London | 2021 |
| Acies International Trade Ltd | London | 2020 |
| Acies Management Holdings Limited | London | 2018 |
| Acies SME UK MGA Limited | London | 2020 |
| Acim Coleford 2 Ltd | London | 2025 |
| Acim Coleford Hampton Ltd | London | 2025 |
| Acim Coleford Holdings Ltd | London | 2025 |
| Acim Coleford P2 Ltd | London | 2025 |
| Acinvest Limited | Scunthorpe | 2021 |
| Acipita Limited | London | 2024 |
| Acis Communities Limited | Gainsborough | 2024 |
| Acis Underwriting Agencies Limited | Bromley | 2003 |
| Acis Ventures (UK) Ltd | Orpington | 2026 |
| ACJ Financial Planning Limited | Rugby | 2026 |
| Acje Group Ltd | Bideford | 2024 |
| Acjk Limited | Market Drayton | 2025 |
| Acjoin Limited | Doncaster | 2007 |
| ACK Malta Holdings Limited | Coventry | 2022 |
| Acker Developments Limited | Dungannon | 1994 |
| Ackerman Pierce Capital Group Ltd | Surbiton | 2026 |
| Ackerman Pierce Holdings Limited | Surbiton | 2025 |
| Ackerman Property Group Limited | Ashford | 2024 |
| Ackhurst Investments Limited | Chorley | 2018 |
| Acklam Financial Limited | Blackpool | 2003 |
| Ackland Wills & Estate Planning Ltd | Bristol | 2021 |
| Ackley Ltd | London | 2019 |
| Ackroyd Group Holdings Ltd | Nottingham | 2025 |
| ACL 2025 Holdings Ltd | Watford | 2025 |
| ACL 28 Ltd | Chertsey | 2024 |
| ACL Autolease Holdings Limited | | 1998 |
| ACL Consultants UK Limited | Bedford | 2025 |
| ACL Corporation Limited | Mayfair | 2026 |
| ACL EOT Limited | Newbury | 2025 |
| ACL Financial Group Internacional Ltd | London | 2024 |
| ACL Holdco Limited | Sheffield | 2023 |
| ACL Holdings (NE) Ltd | Durham | 2019 |
| ACL Holdings North East Limited | Hartlepool | 2026 |
| ACL Investing Limited | London | 2021 |
| ACL Propco Limited | Sheffield | 2023 |
| ACL Trustees Limited | | 2006 |
| Acla Financial Services Limited | Glasgow | 2009 |
| Aclg Limited | Tunbridge Wells | 2024 |
| Aclive Holdings Ltd | Faversham | 2023 |
| Aclop Limited | London | 2023 |
| Aclrs Limited | London | 2017 |
| Aclw Group Holdings Limited | London | 2017 |
| ACM Broking Limited | Tunbridge Wells | 1999 |
| ACM Capital Holdings Ltd | London | 2016 |
| ACM Feilding Portfolio | Oxford | 2021 |
| ACM Finances Limited | Chichester | 2021 |
| ACM Holdco Limited | Glasgow | 2025 |
| ACM Investment I Limited | Oxfordshire | 2024 |
| ACM Investments & Consultancy Limited | Billingham | 2019 |
| ACM Investments UK Ltd | London | 2016 |
| ACM Mortgage Services Limited | Paisley | 2022 |
| ACM Wealth Limited | Stirling | 2025 |
| ACM Wealth Management Ltd | Glasgow | 2013 |
| ACM Wealth Planning Limited | Berks | 2003 |
| Acmb Holdings Limited | Rugby | 2023 |
| Acmca Limited | Beith | 2002 |
| Acme Credit Consultants Limited | West Drayton | 2005 |
| Acme Family Investments Limited | Windsor | 2025 |