| Alderson and Co Consultants Ltd | Professional & scientific | 2023 |
| Alexander Rose Direct Ltd | Wholesale & retail | 2026 |
| Alexander Rose Ltd. | Wholesale & retail | 1994 |
| Algorithm Marketing (PTY) Ltd | Professional & scientific | 2021 |
| ALL Cover Ltd | Administrative & support | 2018 |
| ALL in Bookkeeping and Accountancy Limited | Professional & scientific | 2022 |
| Alland Drylining & Construction Ltd | Construction | 2025 |
| Allstar Air-Conditioning Ltd | Construction | 2020 |
| Alpha Groundworks Limited | Construction | 2021 |
| Alpine Accessories Limited | Wholesale & retail | 2013 |
| Alsapa Ltd | Real estate | 2025 |
| Altea Contracts Limited | Construction | 2024 |
| Always Cinematic Ltd | Information & communication | 2025 |
| Always Dream Big Ltd | Wholesale & retail | 2023 |
| ALX Lighting Limited | Administrative & support | 2018 |
| Amanda Jayne Ltd | Wholesale & retail | 2026 |
| Ambient Designs Ltd | Wholesale & retail | 2023 |
| AMF Management Consultancy Ltd | Professional & scientific | 2018 |
| Amfaeh Ltd | Wholesale & retail | 2024 |
| Amgen Consulting Limited | Professional & scientific | 2019 |
| Ampflow Contractors Ltd | Construction | 2025 |
| Amplified Nutrition Clothing Ltd | Wholesale & retail | 2022 |
| AMT Consulting Solutions Ltd | Professional & scientific | 2014 |
| Anastasia Stein Tax and Accounting Services Ltd | Professional & scientific | 2014 |
| Andalso Improv Ltd | Education | 2023 |
| Andersson Events Ltd | Other services | 2011 |
| Andrew Green Lighting Limited | Information & communication | 2011 |
| Andy Briggs Limited | Information & communication | 2023 |
| Annabelle Horton Photography Ltd | Professional & scientific | 2024 |
| Antenna Dynamics Ltd | Professional & scientific | 2012 |
| Anthony K Webb Limited | Professional & scientific | 2008 |
| Anuya Limited | Wholesale & retail | 2019 |
| AP Roofing Ltd | Construction | 2024 |
| AP Strategic Solutions Limited | Professional & scientific | 2017 |
| Apex Pharma Talent Ltd | Administrative & support | 2024 |
| Appletree Close Management Limited | Real estate | 2020 |
| Aptura Properties Ltd | Construction | 2025 |
| APX Accounting Limited | Information & communication | 2025 |
| Aquora Heating Limited | Construction | 2026 |
| Arbitration Court Reporting Ltd | Professional & scientific | 2014 |
| ARC IT Recruitment Limited | Administrative & support | 2004 |
| Arc-It Consulting Limited | Information & communication | 2021 |
| Archer Acquisition Company Limited | Professional & scientific | 2020 |
| Archer Specialist Treatments Limited | Construction | 1996 |
| Archer Stone Restoration Limited | Construction | 1994 |
| Archer Topco Limited | Professional & scientific | 2020 |
| Arctic Comms Ltd | Professional & scientific | 2019 |
| Ardingly Drive Properties Ltd | Real estate | 2018 |
| Aries Fire Safety Limited | Wholesale & retail | 2019 |
| Arington Ltd | Real estate | 2011 |
| ARJ Contracting Ltd | Professional & scientific | 2020 |
| ARK Construction and Carpentry Ltd | Construction | 2024 |
| Arkavia Ltd | Transport & logistics | 2007 |
| Arranedge Limited | Professional & scientific | 2007 |
| Art Trace Limited | Professional & scientific | 2018 |
| Arya SAN Limited | Administrative & support | 2010 |
| Aryh Limited | Construction | 2026 |
| AS Hygiene Ltd | Health & social care | 2026 |
| Asani Ltd | Construction | 2022 |
| Aspen Court (EG) Management Company Limited | Households | 2005 |
| Aspiration Consultants Limited | Administrative & support | 2021 |
| Aspire Ductwork Services Limited | Manufacturing | 2017 |
| Aspire Education Pathway Ltd | Education | 2024 |
| Aspire Resourcing Solutions Ltd | Administrative & support | 2009 |
| Associated Construction Projects Ltd | Construction | 2006 |
| Association of Studio & Production Equipment Companies Ltd | Other services | 1994 |
| At&Gl Limited | Transport & logistics | 2025 |
| ATD Logistics & Distribution Limited | Transport & logistics | 2023 |
| Athleticoburgesshill Ltd | Arts & recreation | 2016 |
| Athletix Limited | Wholesale & retail | 2026 |
| Atlantic Cleaning Sussex Ltd | Administrative & support | 2017 |
| ATP Consultancy Ltd | Financial services | 2024 |
| Attree and Kent Limited | Extraterritorial | 1904 |
| Audio Visual Architecture Limited | Information & communication | 2008 |
| Augmenta Limited | Professional & scientific | 2004 |
| Auras & Minds Ltd | Health & social care | 2026 |
| Aureo Group Ltd | Extraterritorial | 2014 |
| Aurora Bidco 2 Limited | Administrative & support | 2021 |
| Aurora Community Care Ltd | Health & social care | 2024 |
| Aurora Topco 2 Limited | Administrative & support | 2021 |
| Auto Technologies Ltd | Wholesale & retail | 2016 |
| Automatic Door Installation Association | Other services | 2013 |
| AV Commercial Ltd | Construction | 2025 |
| AV Electrical South Limited | Construction | 2016 |
| AV Refurbishment Ltd | Construction | 2019 |
| Avantech Ltd | Information & communication | 2024 |
| Avenue Academy Limited | Education | 2022 |
| AVS Recruitment Ltd | Administrative & support | 2025 |
| AWB Property Solutions Ltd | Construction | 2021 |
| Axioma Intelligence Ltd | Information & communication | 2026 |
| Axis Facilities Management Limited | Administrative & support | 2014 |
| Azurite Labs Ltd | Professional & scientific | 2024 |
| B a Walker Limited | Wholesale & retail | 2024 |
| B B D Developments Limited | Construction | 2007 |
| B Milligan Holdings Limited | Real estate | 2025 |
| B T G Electrics Ltd | Construction | 2014 |
| B.Cooke Plumbing & Heating Limited | Construction | 2025 |
| B.W. & B.(Park Garages)Limited | Wholesale & retail | 1968 |
| Baan Thai Two Ltd | Hospitality | 2016 |
| Bagatelle Hope Limited | Real estate | 2019 |