| Aphrodite Models Ltd | Other services | 2023 |
| Apollo House Holdings Limited | Real estate | 2021 |
| Apota International Ltd | Wholesale & retail | 2020 |
| Apotek Analytics Ltd | Information & communication | 2021 |
| Apotheosis Renovations Ltd | Administrative & support | 2023 |
| Apparel Gala Ltd | Wholesale & retail | 2023 |
| Apple & Pear Studio Ltd | Manufacturing | 2012 |
| Apple Acre Estate Management Limited | Real estate | 2026 |
| Apple Peel Productions Ltd | Administrative & support | 2012 |
| Appleby & GUY Properties Ltd | Real estate | 2017 |
| Appleby Medical Services Limited | Administrative & support | 2009 |
| Applejacks Burgers Ltd | Information & communication | 2016 |
| Applemore Groundworks and Agriculture Ltd | Construction | 2026 |
| Applewood Joinery Limited | Construction | 2006 |
| Applied Driving Techniques (Global Solutions) Ltd | Professional & scientific | 2008 |
| Applied Karate Ltd | Education | 2023 |
| Applied Learning Solutions Ltd | Information & communication | 2018 |
| Applin Business Ltd | Professional & scientific | 2022 |
| April Maes Catering Ltd. | Hospitality | 2018 |
| APS Mortgages (UK) Ltd | Financial services | 1999 |
| Aptitude Invest Ltd | Administrative & support | 2026 |
| AQ Restaurants Limited | Real estate | 2014 |
| Aqua Assurance Consulting Ltd | Construction | 2026 |
| Aqua Callidus Consulting Ltd | Professional & scientific | 2018 |
| Aqua Platinum Holdings Ltd | Financial services | 2024 |
| Aqua Platinum Projects Ltd | Construction | 2011 |
| Aqua Platinum Servicing Ltd | Other services | 2020 |
| Aqua Platinum Tiling Contractors Ltd | Construction | 2021 |
| Aqua Rush Limited | Financial services | 2023 |
| Aquafinishing Limited | Construction | 2022 |
| Aquatiere Limited | Manufacturing | 2015 |
| ARA Initial II Limited | Financial services | 2025 |
| Aramis Glazing Solutions Ltd | Construction | 2022 |
| ARB Elite Tree Care Ltd | Other services | 2019 |
| Arbenz Holdings Ltd | Professional & scientific | 2026 |
| Arbroath Specsavers Limited | Wholesale & retail | 2003 |
| Arbuthnott Turbines Limited | Energy | 2014 |
| ARC Business Solutions Limited | Professional & scientific | 2018 |
| ARC Cafe Collective Ltd | Hospitality | 2025 |
| ARC Electrical & Mechanical Ltd | Administrative & support | 2017 |
| ARC Fire Safety & Security Ltd | Construction | 2002 |
| ARC Retirement Planning Ltd | Administrative & support | 2021 |
| ARC Scaffolding Limited | Construction | 2025 |
| Arch Transport Solutions Ltd | Transport & logistics | 2018 |
| Archer Exhibitions Ltd | Construction | 2013 |
| Archer Road Specsavers Limited | Wholesale & retail | 2018 |
| Archibald Computing Limited | Information & communication | 2015 |
| Archicraft Designs Limited | Professional & scientific | 2015 |
| Architectural Glazing Solutions Limited | Construction | 2002 |
| Archuno Consulting Ltd | Information & communication | 2026 |
| Arcmaw Ltd | Real estate | 2014 |
| Arctic Air Conditioning Services Limited | Construction | 2012 |
| Arctic FM Limited | Construction | 2008 |
| Arctic Refrigeration Services Limited | Construction | 2008 |
| Ardachy Cottage Ltd | Real estate | 2024 |
| Arden & Way Ltd | Real estate | 2017 |
| Ardis Systems Limited | Wholesale & retail | 1989 |
| AREA36 Fabrications Ltd | Manufacturing | 2022 |
| Aresmo Limited | Health & social care | 2022 |
| Arete Stories Limited | Information & communication | 2013 |
| Aretusa Limited | Hospitality | 2020 |
| Argentum Europe 2016 LLP | | 2020 |
| Argentum Invest I LLP | | 2020 |
| Argentum Invest II LLP | | 2020 |
| Argentum Invest IV LLP | | 2020 |
| Argentum Invest IX LLP | | 2020 |
| Argentum Invest VI LLP | | 2020 |
| Argentum Invest VII LLP | | 2020 |
| Argentum Invest Viii LLP | | 2020 |
| Argentum Invest X LLP | | 2020 |
| Argentum Invest XI LLP | | 2020 |
| Argentum Invest XII LLP | | 2021 |
| Argentum Invest Xiii LLP | | 2021 |
| Argentum Invest XIV LLP | | 2021 |
| Argentum Invest XIX LLP | | 2021 |
| Argentum Invest XV LLP | | 2021 |
| Argentum Invest XVI LLP | | 2021 |
| Argentum Invest Xvii LLP | | 2021 |
| Argentum Invest Xviii LLP | | 2021 |
| Argentum Invest XX LLP | | 2022 |
| Argentum Invest XXI LLP | | 2022 |
| Argentum Invest Xxiii LLP | | 2023 |
| Argentum Invest Xxiv LLP | | 2023 |
| Argentum Invest Xxix LLP | | 2025 |
| Argentum Invest XXV LLP | | 2024 |
| Argentum Invest Xxvi LLP | | 2024 |
| Argentum Invest Xxvii LLP | | 2024 |
| Argentum Invest Xxviii LLP | | 2025 |
| Argentum LB 7 LLP | | 2020 |
| Argentum Secondary III LLP | | 2020 |
| Argo Acquisition Co. Limited | Financial services | 2022 |
| Ariddas Locums Ltd | Administrative & support | 2026 |
| Arijadestore Ltd | Wholesale & retail | 2026 |
| ARK Business Holdings Limited | Financial services | 2026 |
| ARK Computer Repair Ltd | Other services | 2020 |
| Arkatech Ltd | Professional & scientific | 2025 |
| Arkw Ltd | Professional & scientific | 2015 |
| Arlington Flats Management Limited | Households | 1996 |
| Armada Way Specsavers Limited | Wholesale & retail | 1996 |
| Armada Way Visionplus Limited | Wholesale & retail | 1996 |