| Angelacullen 1 Formula Ltd | Professional & scientific | 2024 |
| Angels Hair Collection Ltd | Other services | 2016 |
| Angeluz Limited | Professional & scientific | 2019 |
| Anglonordic Advisory Limited | Professional & scientific | 2016 |
| Another Happy Family Ltd | Hospitality | 2018 |
| Antoines Limited | Other services | 2008 |
| Anuvaayum Ltd | Manufacturing | 2018 |
| AP24 Racing Limited | Arts & recreation | 2016 |
| Aperta Aviation Ltd | Transport & logistics | 2021 |
| Apex Social Care Limited | Financial services | 2022 |
| Apollo Multi Asset Management LLP | | 2008 |
| Apple Procurement Limited | Professional & scientific | 2014 |
| Aptus Technology Limited | Information & communication | 2002 |
| Apwr Limited | Professional & scientific | 2010 |
| Aquagem Beauty Ltd | Other services | 2010 |
| Aquis Engineering Limited | Construction | 2021 |
| Arabellas Logistics Limited | Other services | 2017 |
| Arabian Brewing Company UK Ltd | Manufacturing | 2023 |
| Aralco Limited | Professional & scientific | 1998 |
| ARC Build Global Limited | Construction | 2020 |
| ARC Group Global Ltd | Professional & scientific | 2019 |
| ARC Power Ltd | Energy | 2014 |
| ARC Ride Limited | Transport & logistics | 2020 |
| Architech IT Services Limited | Information & communication | 2025 |
| Architectural Plants Limited | Agriculture & fishing | 1990 |
| Ardent Care Connect Services Limited | Health & social care | 2021 |
| Ardent Contracts Limited | Construction | 2019 |
| Area Squared Ltd | Professional & scientific | 2023 |
| Argonaut Paraplanning Consultants Ltd | Financial services | 2013 |
| ARK Pumps Limited | Wholesale & retail | 2018 |
| Arklow House Limited | Professional & scientific | 2022 |
| Arllstar Ltd | Education | 2024 |
| Armstrong Property Development Ltd | Real estate | 2025 |
| Art of Living (Reigate) Limited | Wholesale & retail | 1991 |
| Artdott Limited | Professional & scientific | 2025 |
| Artful Rigging Co Limited | Administrative & support | 2017 |
| Artryx Consulting Ltd | Professional & scientific | 2019 |
| ASH Villas Residents Management Limited | Real estate | 2025 |
| Ash-Consulting.Com Limited | Professional & scientific | 2006 |
| Ashburnham Investments Limited | Real estate | 2018 |
| Ashdown Commercial Limited | Real estate | 2014 |
| Ashdown Motor Services Limited | Wholesale & retail | 2007 |
| Ashley Louise Limited | Extraterritorial | 2003 |
| Ashtead Developments Limited | Construction | 2009 |
| Asiancontinental Ltd | Professional & scientific | 2016 |
| Asias Land Limited | Financial services | 2022 |
| Asic Health Limited | Health & social care | 2019 |
| Asin Limited | Real estate | 2022 |
| Asmith Consulting Ltd | Professional & scientific | 2017 |
| ASP (Argyll) Limited | Real estate | 2025 |
| ASP (Borden) Limited | Real estate | 2025 |
| ASP (Canterbury) Limited | Construction | 2023 |
| ASP (Coxheath) Limited | Construction | 2024 |
| ASP (Halling) Ltd | Real estate | 2023 |
| ASP (Horley) Limited | Real estate | 2022 |
| ASP Care Developments - Bedhampton Limited | Real estate | 2025 |
| ASP Care Developments - Clandon Limited | Real estate | 2025 |
| ASP Care Developments - Coleford Limited | Real estate | 2025 |
| ASP Care Developments - Effingham Limited | Real estate | 2025 |
| ASP Care Developments - Fleckney Limited | Real estate | 2025 |
| ASP Care Developments - Horley Limited | Real estate | 2025 |
| ASP Care Developments - Potton Limited | Real estate | 2025 |
| ASP Care Developments - Sileby Limited | Real estate | 2025 |
| ASP Care Developments - South Petherton Limited | Real estate | 2025 |
| ASP Care Developments - Whitstable Limited | Real estate | 2025 |
| ASP Care Developments - Wincanton Limited | Real estate | 2025 |
| ASP Care Developments - Wollaston Limited | Real estate | 2025 |
| ASP Care Developments-Clandon Build Limited | Real estate | 2025 |
| ASP Dunham OP Limited | Real estate | 2026 |
| ASP Dunham Prop Limited | Real estate | 2026 |
| Aspect Horticultural Services Ltd | Administrative & support | 2024 |
| Aspire Aviation Limited | Administrative & support | 2023 |
| Aspire Boat Sales Limited | Wholesale & retail | 2009 |
| Aspire Care Developments - on Limited | Financial services | 2025 |
| Aspire Care Developments Limited | Real estate | 2025 |
| Aspire Dunham Care Limited | Real estate | 2023 |
| Aspire Land (West) Limited | Real estate | 2025 |
| Aspire LPP Group Limited | Real estate | 2019 |
| Aspire LPP Limited | Real estate | 2019 |
| Aspire More TEN Ltd | Construction | 2020 |
| Aspire More Twelve Limited | Construction | 2024 |
| Aspire Prop Co Limited | Real estate | 2022 |
| Aspireneer Consulting Limited | Professional & scientific | 2024 |
| Astral Car Centre Limited | Wholesale & retail | 2004 |
| Astrum Properties Ltd | Real estate | 2022 |
| Asyst Call Centre Limited | Administrative & support | 2013 |
| Asyst Group Limited | Financial services | 2004 |
| Asyst Holdings Limited | Financial services | 2007 |
| Asyst Limited | Information & communication | 2004 |
| AT Rubie Ltd | Professional & scientific | 2024 |
| ATF Sound Ltd | Information & communication | 2017 |
| ATG Corporation Limited | Professional & scientific | 2025 |
| Atherfield Homes Ltd | Construction | 2023 |
| Atherfield Park View Road Management Co Ltd | Households | 2024 |
| Athletix Kidz Franchising Ltd | Professional & scientific | 2024 |
| Athletix Kidz Limited | Arts & recreation | 2016 |
| Atkins Groundworks Limited | Construction | 2017 |
| Atlantic Tech Ltd | Information & communication | 2021 |
| Atlas & Quill Ltd | Wholesale & retail | 2025 |
| Atob Ltd | Professional & scientific | 2017 |