| Apie Property Solutions Ltd | Real estate | 2024 |
| Apivale Ltd | Transport & logistics | 2020 |
| APJ Construction Ltd | Construction | 2016 |
| Apjb Ltd | Wholesale & retail | 2025 |
| Apna Basket Limited | Wholesale & retail | 2024 |
| APOLLO24 Healthcare Services Ltd | Health & social care | 2022 |
| Apolonas Ltd | Transport & logistics | 2018 |
| Apple Cabs South Ltd | Transport & logistics | 2018 |
| Appletons Wool Limited | Wholesale & retail | 2013 |
| Application Centric Services Ltd | Other services | 2019 |
| Applistructure Consulting Ltd | Professional & scientific | 2026 |
| Appnova Solutions Limited | Information & communication | 2025 |
| Approach Consultancy Services Ltd | Professional & scientific | 2018 |
| APS Accountancy Holdings Limited | Financial services | 1998 |
| APS Accountancy Limited | Professional & scientific | 2011 |
| APS Nominees Limited | Extraterritorial | 2011 |
| Apsley Manor Farm Limited | Agriculture & fishing | 2013 |
| AQ Travel Limited | Transport & logistics | 2024 |
| Aqua One Solutions Ltd | Construction | 2017 |
| Aquaesea Limited | Professional & scientific | 2016 |
| Aquafi Ltd | Information & communication | 2024 |
| Aquaforest Ltd | Information & communication | 2001 |
| Aquatic Therapy Association of Chartered Physiotherapists | Health & social care | 2020 |
| Aquila Aviation Corporation Ltd | Education | 2026 |
| AR Intech Ltd | Construction | 2020 |
| AR Security Limited | Administrative & support | 2026 |
| Ar-Razaaq Limited | Health & social care | 2016 |
| Araa Solutions Limited | Information & communication | 2022 |
| Arana Clothing Co. Ltd | Wholesale & retail | 2025 |
| Araventures UK Ltd | Wholesale & retail | 2025 |
| ARB Keystone Ltd | Real estate | 2013 |
| ARB Windows Limited | Construction | 2018 |
| Arba Installations Ltd | Construction | 2020 |
| Arbitrate Ltd | Information & communication | 2018 |
| ARC Deco Limited | Construction | 2014 |
| ARC Inventory Limited | Real estate | 2023 |
| ARC Landscaping Limited | Administrative & support | 2023 |
| ARC Solutions PVT Ltd | Information & communication | 2012 |
| Arca Innovations Ltd | Information & communication | 2026 |
| Arcade Properties Ltd | Real estate | 2024 |
| Arcella HR Solutions Ltd | Administrative & support | 2024 |
| Archer (London) Limited | Real estate | 1948 |
| Arcturus Building and Construction Limited | Construction | 1976 |
| Arcus Private Ltd | Transport & logistics | 2025 |
| Arcvam Properties Ltd | Real estate | 2021 |
| Arcwise Ltd | Information & communication | 2021 |
| ARD Transport Services Limited | Transport & logistics | 2016 |
| Arenal Partnership Ltd | Professional & scientific | 2026 |
| Arfsolar Ltd | Energy | 2025 |
| Argo Supplies Ltd | Construction | 2018 |
| Ariala Ltd | Information & communication | 2025 |
| Ariella & Uriela Ltd | Health & social care | 2016 |
| Aritco UK Limited | Wholesale & retail | 2012 |
| Arivaalayam Tamil School Aylesbury Ltd | Education | 2025 |
| ARK Group FM Ltd | Construction | 2025 |
| ARK Solutions 2021 Ltd | Real estate | 2021 |
| Arkangel Medical Limited | Health & social care | 2019 |
| Arlo Electrical Installations Ltd | Construction | 2025 |
| Arlo Exec Ltd | Other services | 2021 |
| Arnold Homes Limited | Construction | 1999 |
| Arnot Development Consultancy Ltd | Professional & scientific | 2021 |
| Arnott Accounting Services Limited | Professional & scientific | 2015 |
| Aroma Trading Limited | Manufacturing | 1992 |
| ARP Projects Ltd | Construction | 2021 |
| Arpra Limited | Health & social care | 2025 |
| Arrk Properties Ltd | Real estate | 2021 |
| Arrow Compliance Training Limited | Education | 2016 |
| Arrow Plumbing Ltd | Construction | 2021 |
| ARS Consultancy Ltd | Professional & scientific | 2015 |
| ARS Homes Ltd | Real estate | 2025 |
| ARS Solutions Limited | Information & communication | 2016 |
| Arshad Brothers Ltd | Hospitality | 2024 |
| Art and Minds Ltd | Information & communication | 2023 |
| Art Tiling & Bathrooms Ltd | Construction | 2026 |
| Arte Digital Ltd | Information & communication | 2016 |
| Artha Wealth Management Ltd | Financial services | 2021 |
| Arthentic Creatives CIC | Arts & recreation | 2024 |
| Arthur Cliffe Planning Services Limited | Professional & scientific | 2003 |
| Arthur Gill Ltd | Professional & scientific | 2021 |
| Arthyconsulting Ltd | Information & communication | 2019 |
| Arti&Son Ltd | Wholesale & retail | 2021 |
| Artillery House Freehold Limited | Households | 2025 |
| Artillery Mansions Limited | Construction | 1997 |
| Artimistik Ltd | Arts & recreation | 2025 |
| Artis Cleaning Services Limited | Administrative & support | 2025 |
| Artis Group Holdings Ltd | Financial services | 2024 |
| Artis Plumbing & Heating Ltd | Construction | 2024 |
| Artis Property Renovations Ltd | Construction | 2023 |
| Artis Property Services Ltd | Construction | 2018 |
| Artistry Beauty Ltd | Other services | 2024 |
| Artluxe Supplies Limited | Wholesale & retail | 2022 |
| Artura DEV 1 Ltd | Construction | 2024 |
| Artura DEV 2 Ltd | Construction | 2025 |
| Artura DEV 3 Ltd | Construction | 2025 |
| Artura DEV 4 Ltd | Construction | 2025 |
| Artura Developments Ltd | Construction | 2024 |
| Artura Group Ltd | Real estate | 2020 |
| Artura Land 1 Ltd | Real estate | 2024 |
| Artura Land Acquisitions Ltd | Real estate | 2024 |
| Arty Goodies Ltd | Wholesale & retail | 2025 |