| Asset Wellness Management Limited | Glasgow | 2020 |
| Asset-Fix Ltd | King'S Lynn | 2022 |
| ASSET259 Ltd | London | 2025 |
| Assets for Life Ltd | Chelmsford | 2016 |
| Assets Inn Limited | London | 2021 |
| Assets of JMT Ltd | Bristol | 2018 |
| ASSETS4CHANGE Community Interest Company | Knutsford | 2024 |
| Assetta Consult Limited | Stevenage | 2018 |
| Assiato Ltd | London | 2024 |
| Assiduous Consultancy Solution Limited | Grays | 2016 |
| Assiduous Ltd | Chatham | 2018 |
| Assignment Seven Limited | Pershore | 2018 |
| Assiluxe Ltd | London | 2026 |
| Assimilate Learning Limited | Fareham | 2019 |
| Assisi Pet Funeral Services Limited | Wirral | 2013 |
| Assist Health & Safety Limited | Grimsby | 2010 |
| Assist Prime Ltd | Mildenhall | 2025 |
| Assist Protect Limited | Derby | 2010 |
| Assist Travel Limited | Birmingham | 2011 |
| Assist VIP Travel Limited | Birmingham | 2016 |
| Assist&Security Ltd | Cardiff | 2017 |
| Assistance Dogs (UK) | Princes Risborough | 2006 |
| Assistant Directors Guild UK Limited | London | 2020 |
| Assisted by JB Ltd | Abergele | 2024 |
| Assisted Recoveries (U.K.) Limited | Pudsey Leeds | 1994 |
| Assoc of Master Tradesmen Limited | Brighton | 2016 |
| Assoc. of Consultation and Engagement Professionals Ltd | Caistor | 2023 |
| Assoc. of Heritage Engineers Limited | Wallingford | 2020 |
| Associate Trainers Limited | Wickford | 2014 |
| Associated Alarms Ltd | Chester | 2022 |
| Associated Asphalt Technologies Ltd | London | 2020 |
| Associated Bearing Co Limited | Cradley Heath | 1996 |
| Associated Beauty Therapists Ltd | London | 2007 |
| Associated Business Solutions Ltd | Waterlooville | 2012 |
| Associated Carpet Group Limited | Wigan | 1985 |
| Associated CD Limited | Huddersfield | 2003 |
| Associated Commerce & Securities Limited | Okehampton | 2002 |
| Associated Continuity Teams Limited | London | 2006 |
| Associated Emergency Medical Centers (Holdings) Limited | London | 1999 |
| Associated Independent Electrical Wholesalers Limited | Ilkeston | 2001 |
| Associated Independent Stores Limited | Solihull | 1967 |
| Associated Liver Launderettes Limited | Liverpool | 1964 |
| Associated National Electrical Wholesalers Limited | Hitchin | 1993 |
| Associated Retirement Community Operators Limited | London | 2012 |
| Associated Rework Solutions Limited | Fareham | 2017 |
| Associated Shipbroking (London) Ltd | London | 2022 |
| Associated Stairlifts Limited | Leicester | 1998 |
| Associated Technology Services (Energy) Ltd | Clevedon | 2015 |
| Associated Training Services Group Ltd | London | 2019 |
| Associated Vending Services Limited | Tamworth | 1988 |
| Associated Waste Group Ltd | Grays | 2007 |
| Associated Waste Land Management Ltd | Grays | 2007 |
| Associates Hair, Body and Mind Limited | Durham | 2012 |
| Associates in Clinical Psychology Ltd | London | 2014 |
| Associates Southampton Limited | Plymouth | 2018 |
| Associates Winchester Limited | Chandler'S Ford | 2017 |
| Association DES Senegalais(Es) DU Royaume-Uni (Asru) | London | 2014 |
| Association for Accountancy & Business Affairs Ltd | Essex | 1997 |
| Association for Art History | London | 2013 |
| Association for Black Engineers (UK) Limited | London | 2008 |
| Association for Business Psychology Limited | Manchester | 2002 |
| Association for Clinical Data Management Limited | Wantage | 2001 |
| Association for Coaching | London | 2002 |
| Association for Coaching International Limited | London | 2009 |
| Association for Consultancy and Engineering | London | 1913 |
| Association for Contemporary Jewellery Limited | London | 2006 |
| Association for Continence Professionals | London | 1995 |
| Association for Curators and Programmers of Asian Cinemas CIC | Newcastle Upon Tyne | 2025 |
| Association for Environment Conscious Building | Huddersfield | 2005 |
| Association for Families of Independent Schooling (Afis) C.I.C. | Portsmouth | 2025 |
| Association for Financial Markets in Europe | London | 2009 |
| Association for Interactive Media and Micropayments Ltd | Farnham | 2008 |
| Association for Mathematics in Education | Loughborough | 2006 |
| Association for Nutrition | Ipswich | 2008 |
| Association for Professional Executive Coaching & Supervision | Woking | 2005 |
| Association for Qualitative Research Limited | Finchley | 1990 |
| Association for Rational Emotive Behaviour Therapy | Hitchin | 2002 |
| Association for Research in the Voluntary and Community Sector (Arvac) | Norwich | 1987 |
| Association for Solution Focus in Organisations Limited | Middlesex | 2016 |
| Association for Solution Focused Hypnotherapy Limited | Bristol | 2010 |
| Association for Specialist Fire Protection | Coventry | 1976 |
| Association for Standards and Practices in Electronic Trade - EAN UK Limited | London | 2004 |
| Association for Student Residential Accommodation | Redditch | 2021 |
| Association for Survey Computing CIC | London | 2022 |
| Association for the Conservation of Energy Limited | London | 1982 |
| Association for the Education and Guardianship of International Students | Stonehouse | 1997 |
| Association for Video Interaction Guidance UK | London | 2012 |
| Association for Yoga Studies (AYS) Limited | New Milton | 2019 |
| Association of Acupuncture Clinicians Ltd. | Macclesfield | 2021 |
| Association of Advanced Biostructural Correction -- Europe (Abc-E) Ltd | Falkirk | 2018 |
| Association of Aesthetics Injectable Cosmetics Limited | Grantham | 2012 |
| Association of Air Ambulances Limited | Birmingham | 2012 |
| Association of Anaesthesia Associates | Cullompton | 2008 |
| Association of Anaesthetists Enterprises Limited | London | 2025 |
| Association of Black Event Professionals Limited | London | 2021 |
| Association of Breast Surgery | London | 2010 |
| Association of British Certification Bodies | Shrewsbury | 1996 |
| Association of British Chinese Professors | Cambridge | 2018 |
| Association of British Choral Directors | London | 2000 |
| Association of British Healthtech Industries Limited | London | 1979 |