| ALL Cube Holdings Limited | Financial services | 2015 |
| ALL Cube Limited | Administrative & support | 2008 |
| ALL Materials Handling Ltd | Administrative & support | 2018 |
| ALL Things Studio Limited | Administrative & support | 2014 |
| Allderwyne Ltd | Manufacturing | 2025 |
| Allen & Sons Maintenance Ltd | Construction | 2011 |
| Allied Electrical Security Limited | Administrative & support | 1997 |
| Alpha Labels and Signs Limited | Manufacturing | 1994 |
| Alphabetter Limited | | 1974 |
| Alphamolly Limited | Information & communication | 2021 |
| AM Grey Holdco Ltd | Financial services | 2025 |
| Amac Investments Ltd | Real estate | 2014 |
| Amarti Ltd | Professional & scientific | 2020 |
| Amata Interiors Limited | Professional & scientific | 2025 |
| Amateur Poker Limited | Arts & recreation | 2005 |
| Amazing Gifts Limited | Wholesale & retail | 2004 |
| AMG Carrier Ltd | Transport & logistics | 2020 |
| Amin Jahan Ltd | Hospitality | 2019 |
| AML Consultants Limited | Professional & scientific | 1994 |
| Amron London Limited | Health & social care | 2025 |
| AN Prop Limited | Households | 2023 |
| Anatine Limited | Real estate | 2013 |
| Anderson Family Property Ltd | Real estate | 2025 |
| Anderson Management (UK) Ltd | Construction | 2011 |
| Andrews Property Renovation Ltd | Real estate | 2012 |
| Andromeda Property LLP | | 2018 |
| Angels Paws Rescue CIC | Other services | 2026 |
| Anglin Security UK Ltd | Administrative & support | 2024 |
| Animist Studio Limited | Information & communication | 2020 |
| Ankita Enterprise PVT Ltd. | Wholesale & retail | 2026 |
| Another Way Theatre Ltd | Arts & recreation | 2016 |
| Anther Healthcare Ltd | Wholesale & retail | 2022 |
| Anthony's Property Management Limited | Real estate | 2026 |
| APA Insights Limited | Administrative & support | 2020 |
| Appcntrl Limited | Information & communication | 2021 |
| Apps Construction Ltd | Construction | 2013 |
| Aquafilms Limited | Administrative & support | 2008 |
| Aquillo Accounting Ltd | Professional & scientific | 2016 |
| AR Barbers Ltd | Other services | 2024 |
| Arandal Properties Limited | Health & social care | 2010 |
| Arbpec Ltd | Real estate | 2021 |
| Arcgeolink Limited | Professional & scientific | 2015 |
| Arch Consultants Avis Limited | Financial services | 2021 |
| Arch Consultants Hardy Limited | Financial services | 2021 |
| Arch Electrical Contractors Ltd | Construction | 2024 |
| Arctenon Ltd | Manufacturing | 2025 |
| Arden & Grace Limited | Financial services | 2026 |
| Aries Advisory Ltd | Professional & scientific | 2019 |
| Aristos Properties Ltd | Real estate | 2019 |
| Arjun Property Ltd | Real estate | 2012 |
| Arko Creatives Ltd | Construction | 2025 |
| Arminius Limited | Real estate | 1988 |
| Arminius Property Ltd | Real estate | 2021 |
| ARN Yacht Limited | Professional & scientific | 2023 |
| Arteaga Ltd | Real estate | 2026 |
| Artis Telecom Ltd | Information & communication | 2017 |
| Arts Consultancy Ltd | Professional & scientific | 2016 |
| Aryan Computer Associates Limited | Information & communication | 1999 |
| AS Medical Consultancy Ltd | Health & social care | 2026 |
| Ascendancy Partners Limited | Hospitality | 2015 |
| ASH Surveyors Ltd | Professional & scientific | 2012 |
| Ashtead Property Ltd | Real estate | 2018 |
| ASN Air Conditioning Ltd | Construction | 2025 |
| Aspiringu Ltd | Other services | 2018 |
| Asprey's Residents Association Limited | Real estate | 2007 |
| Asset Care Group Ltd | Construction | 2025 |
| Asset Guard Group Ltd | Information & communication | 2025 |
| Associated Welding Supplies Ltd | Construction | 2009 |
| Assured Home Solutions Limited | Construction | 2023 |
| Asteri Management Limited | Professional & scientific | 2022 |
| Aston Medcare Ltd | Administrative & support | 2019 |
| ATA Property Partners Ltd | Real estate | 2025 |
| Atallah Ltd | Real estate | 2025 |
| ATD Developments Ltd | Construction | 2018 |
| Atkins Special Risks Limited | Financial services | 1995 |
| Atlas Products Limited | Wholesale & retail | 2017 |
| Attiki Art Limited | Arts & recreation | 2022 |
| Auctions First Limited | Real estate | 2008 |
| Audiotube Limited | Arts & recreation | 2006 |
| Aura Building Concepts Ltd | Construction | 2016 |
| Autobodyplus Ltd | Wholesale & retail | 2025 |
| Autostrada Inspections Ltd | Construction | 2023 |
| Auxiliary Biocgt Consulting Ltd | Professional & scientific | 2024 |
| Avaco Scaffolding Ltd | Construction | 2016 |
| Avanti Financial Planning Limited | Financial services | 2023 |
| Avar Logistics Ltd | Transport & logistics | 2021 |
| Avenir Consulting Limited | Professional & scientific | 2015 |
| Avis Investments Limited | Real estate | 2023 |
| Avmk Accountants Limited | Professional & scientific | 2022 |
| Avmk Commercial Finance Ltd | Financial services | 2025 |
| Avmk Homes Ltd | Real estate | 2022 |
| Avondale (Freehold) Limited | Real estate | 1997 |
| AVP Construction Ltd | Construction | 2014 |
| AW Equity Limited | Real estate | 2023 |
| Awaken Potential Ltd | Education | 2026 |
| Axial Properties (UK) Ltd | Real estate | 2001 |
| Ayling Scaffolding Limited | Construction | 2020 |
| B & S Construction Consultants Ltd | Professional & scientific | 2024 |
| B a Wellbeing Ltd | Health & social care | 2019 |
| B&N Partners Limited | Administrative & support | 2026 |