| Approved Access Services (SW) Ltd | Construction | 2020 |
| Approved Cleaning Services (SW) Ltd | Administrative & support | 2020 |
| APS Locum Ltd | Professional & scientific | 2023 |
| APS Property Holdings Ltd | Real estate | 2017 |
| APY Electrical Services Ltd | Construction | 2026 |
| Aquabats Ltd | Construction | 2021 |
| Aquablast Drain Services Limited | Administrative & support | 2002 |
| Aqualex Ltd | Wholesale & retail | 2026 |
| Aqueous UK Limited | Information & communication | 2009 |
| AR Proptech Ltd | Households | 2024 |
| Arabela Ltd | Hospitality | 2025 |
| Arancini Ltd | Hospitality | 2018 |
| Ararat Barbers Limited | Other services | 2016 |
| Arbd Awareness Consultancy Ltd | Professional & scientific | 2026 |
| Arbre Limited | Administrative & support | 2019 |
| ARC Masterworks Ltd | Construction | 2017 |
| Arcadia (South West) Limited | Professional & scientific | 2002 |
| Architectural Elegance Limited | Manufacturing | 2023 |
| Archology Data Limited | Information & communication | 2023 |
| Arctos Developments Ltd | Real estate | 2020 |
| ARD Technical Services Limited | Construction | 2020 |
| Ardor Electrical Limited | Construction | 2014 |
| Ardua Property Management Limited | Real estate | 2019 |
| Area M Custom Engineering Ltd | Manufacturing | 2009 |
| Arfco Ltd | Real estate | 2017 |
| Argtech Ltd | Information & communication | 2018 |
| Arican Retail Limited | Wholesale & retail | 2026 |
| Ariel Solution Design Limited | Information & communication | 2014 |
| Aries VIP Limited | Arts & recreation | 2020 |
| Arken Media Ltd | Information & communication | 2020 |
| Arlington (Paragon) Ltd | Real estate | 2011 |
| Arlington TX Limited | Real estate | 1982 |
| Armec Engineering Services Ltd | Construction | 2026 |
| Armistead Omalley Property Ltd | Real estate | 2025 |
| Arnold Contracting Ltd | Construction | 2019 |
| Art Galleries of Bath Limited | Wholesale & retail | 1997 |
| Art Transport 87 Ltd | Transport & logistics | 2023 |
| Artemis AI Limited | Information & communication | 2026 |
| Artifice Solutions Limited | Information & communication | 2023 |
| Artvue Limited | Manufacturing | 2010 |
| Arundell Court (Weston-Super-Mare) Limited | Households | 1974 |
| Arwa Foods Ltd | Hospitality | 2025 |
| Arwendell Ltd | Real estate | 2025 |
| Arya Aesthetics Ltd | Health & social care | 2023 |
| Aryan Foods Limited | Hospitality | 2018 |
| Aryan Medics Ltd | Other services | 2011 |
| ASC Commercial Ltd | Real estate | 2004 |
| Ascension Quality Ltd | Professional & scientific | 2018 |
| Ascot Group (Holdings) Limited | Professional & scientific | 2012 |
| Ascot House (WSM) Ltd | Real estate | 2024 |
| Ascot Property Management Limited | Real estate | 2016 |
| Asdala Ltd | Wholesale & retail | 2021 |
| ASENA3 Limited | Hospitality | 2015 |
| ASENA4 Limited | Wholesale & retail | 2017 |
| ASF Locksmiths Limited | Manufacturing | 2013 |
| ASH Life Sciences Ltd | Professional & scientific | 2016 |
| Ashcombe Estate Agents and Lettings Ltd | Real estate | 2022 |
| Ashcombe House (Burnham-On-Sea) Management Limited | Households | 1984 |
| Ashcombe Management (WSM) Company Limited | Households | 2014 |
| Ashdene Management Company Limited | Households | 1983 |
| Ashley Enterprises Ltd | Wholesale & retail | 2014 |
| Ashley Leahy Estate Agents Limited | Real estate | 2025 |
| Ashton&Southville Damp Proofing Ltd | Construction | 2022 |
| Ashworth-Von Bernhardi Ltd. | Professional & scientific | 2020 |
| Ask-The-Markets Limited | Professional & scientific | 2014 |
| Ason UK 2015 Ltd | Construction | 2015 |
| Aspect Property Solutions Ltd | Real estate | 2005 |
| Aspen Joinery Ltd | Manufacturing | 2005 |
| Aspire Studios Ltd | Information & communication | 2023 |
| ASR Consulting Limited | Information & communication | 2017 |
| Asset Data Management Ltd | Information & communication | 2025 |
| Associated Independent Assessors Limited | Financial services | 1984 |
| Astapor Content Limited | Wholesale & retail | 2016 |
| Astleigh House (Management Company) Limited | Hospitality | 1988 |
| Aston Consultancy Limited | Professional & scientific | 2006 |
| Astute Code Ltd | Information & communication | 2016 |
| AT & OL Ltd | Administrative & support | 2014 |
| AT2 Trading Limited | Wholesale & retail | 2023 |
| Aterford Property Management Limited | Households | 1986 |
| Atkins Accountancy Services Limited | Professional & scientific | 2008 |
| Atkins Marine Services Ltd | Manufacturing | 2022 |
| Atkinson House Management Company Limited | Extraterritorial | 2007 |
| Atlantic Court Maintenance Company Limited | Households | 1974 |
| Atlantic Fish Meadow Ltd | Hospitality | 2025 |
| Atlantic House (Weston-Super-Mare) Limited | Households | 1989 |
| Atlantic Manor Ltd | Wholesale & retail | 2026 |
| Atlantic Village Limited | Administrative & support | 2018 |
| Attestari Holdings Ltd | Information & communication | 2026 |
| Attestari Immutis Ltd | Information & communication | 2026 |
| AU Recruit Ltd | Administrative & support | 2017 |
| Audio Cabinet Construction Ltd | Manufacturing | 2010 |
| Audio Visual Direct Limited | Wholesale & retail | 2010 |
| Audionation-Uk Limited | Wholesale & retail | 2008 |
| Augmented Reality Creations Ltd | Information & communication | 2020 |
| Auralets Limited | Hospitality | 2026 |
| Aureus Wealth Management Ltd | Financial services | 2022 |
| Aurora Lifesciences Ltd | Administrative & support | 2023 |
| Aurora Skies Limited | Transport & logistics | 2022 |
| Auto Mots and Servicing Ltd | Wholesale & retail | 2019 |
| Auto Rescue Somerset Limited | Manufacturing | 2017 |