| 23C Ltd | Professional & scientific | 2024 |
| 360 Picture Solutions UK Limited | Professional & scientific | 2017 |
| 3H Learning Solutions Ltd | Professional & scientific | 2023 |
| 3M Drives & Controls Ltd | Manufacturing | 2025 |
| 89 Church Road Limited | Real estate | 2017 |
| A & J Property Holdings and Investment Ltd | Real estate | 2021 |
| A & M Berry Properties Ltd | Real estate | 2026 |
| A & N Property Management Ltd | Real estate | 2024 |
| A Burgess Ltd | Wholesale & retail | 2009 |
| A J Beaman Holdings Limited | Real estate | 2016 |
| A&J New Homes Limited | Construction | 2017 |
| A&S Employment Services Limited | Professional & scientific | 2025 |
| A.I.R. Cladding Supplies Limited | Manufacturing | 2011 |
| A.J.Beaman (Construction) Limited | Construction | 2002 |
| A.P.T Lettings Limited | Real estate | 2009 |
| A.R.M. Construction Management Limited | Construction | 2016 |
| A.S.L.R. Fabrication Services Ltd. | Manufacturing | 1992 |
| A1 Airsoft Ltd | Wholesale & retail | 2025 |
| A1 Motor Services Limited | Wholesale & retail | 2006 |
| A1 Paraplanning Services Limited | Financial services | 2016 |
| A1CAD Ltd | Professional & scientific | 2025 |
| Abrafoam Limited | Administrative & support | 1996 |
| Absolute Branding Limited | Wholesale & retail | 2018 |
| Accelerate Marketing and Marketing Research Ltd | Professional & scientific | 2013 |
| Access Services & Consultancy Ltd | Construction | 2021 |
| ACG Occupational Therapy Limited | Health & social care | 2019 |
| ACH Developments Limited | Real estate | 2022 |
| Acheron Care Limited | Health & social care | 2019 |
| Acheron Consultancy Services Limited | Information & communication | 2023 |
| Acheron Property Limited | Real estate | 2024 |
| ACN Consulting Ltd | Information & communication | 2015 |
| Active Life Physiocare Ltd | Health & social care | 2016 |
| Acupoint Ltd | Administrative & support | 2013 |
| Addstone (UK) Limited | Wholesale & retail | 1999 |
| Advance Carpentry Ltd | Construction | 2011 |
| Advanced Journey Chauffeuring Limited | Transport & logistics | 2017 |
| Advanced Postformed Systems Limited | Manufacturing | 2010 |
| Advanced Solutions Midlands Ltd | Administrative & support | 2017 |
| AER Garden Services Ltd | Administrative & support | 2020 |
| Aesthetics by ELA Ltd | Health & social care | 2025 |
| Agentices Limited | Information & communication | 2026 |
| Air Group Investments Limited | Financial services | 2014 |
| Aize Properties Limited | Real estate | 2025 |
| AKA Shaw Consulting Ltd | Professional & scientific | 2016 |
| Akay UK Consultancy Ltd | Hospitality | 2021 |
| AKS Machine Hire Limited | Wholesale & retail | 2025 |
| AL Driver Hire Limited | Transport & logistics | 2022 |
| Alan Parker Associates Limited | Real estate | 1997 |
| Albany Developments Limited | Construction | 1986 |
| Alex Wright Consulting and Training Ltd | Professional & scientific | 2025 |
| Alison & IAN Woodcock Ltd | Wholesale & retail | 2018 |
| Alive Publishing Limited | Other services | 1988 |
| ALL About YOU (Ellesmere) Limited | Other services | 2023 |
| ALL My Thoughts Ltd | Information & communication | 2024 |
| ALL Things Boutique Limited | Wholesale & retail | 2016 |
| Alleyne's Academy | Education | 2013 |
| Alsecco (U.K.) Limited | Manufacturing | 2024 |
| Am-Advanced Ltd | Information & communication | 2025 |
| Amadu Care Ltd | Health & social care | 2018 |
| Ambas Limited | Real estate | 1980 |
| AMC Consultancy Solutions Services Limited | Administrative & support | 2025 |
| Amea Leisure Limited | Hospitality | 2024 |
| AMG Care Services Group Limited | Financial services | 2012 |
| AMG Consultancy Services Limited | Health & social care | 1985 |
| AMG Medico Legal Limited | Health & social care | 1997 |
| Amphora Marketing Limited | Wholesale & retail | 2011 |
| Amplify by Chloe Limited | Hospitality | 2024 |
| Amricc Ltd | Professional & scientific | 2016 |
| AMY Seabridge Ltd | Agriculture & fishing | 2011 |
| Ancestry Residents Management Ltd | Households | 2025 |
| Anchor Place Buildings Limited | Professional & scientific | 2009 |
| AND Then There WAS One Holdings Limited | Financial services | 2025 |
| Angel Associates Limited | Administrative & support | 2022 |
| Angel Business Finance Limited | Financial services | 2021 |
| Angel Finance & Mortgages Limited | Financial services | 2021 |
| Angelcare Corporate UK Limited | Wholesale & retail | 2007 |
| Anna Locum Ltd | Health & social care | 2021 |
| Apex Building Control Ltd | Construction | 2025 |
| Aphellion Digital Ltd | Information & communication | 2024 |
| Applied Materials Research Innovation and Commercialisation Company Ltd | Professional & scientific | 2016 |
| Apro Plumbing & Heating Limited | Construction | 2006 |
| APS (2017) Limited | Wholesale & retail | 2017 |
| Aqua Crystal UK Limited | Extraterritorial | 2012 |
| Aquafix Ltd | Construction | 2024 |
| Aquaventures Swim School Ltd | Education | 2019 |
| Aqueco Ltd | Construction | 2008 |
| Aquina (Railway) Ltd | Real estate | 2019 |
| Aquina Community Limited | Real estate | 2021 |
| Aquina Investments Limited | Real estate | 2017 |
| Aquina Staffordshire Ltd | Financial services | 2025 |
| Aquina Tunstall PC Ltd | Hospitality | 2017 |
| AR Rail Limited | Professional & scientific | 2022 |
| Arabpeacock Interactive Learning Limited | Education | 2016 |
| ARB Marketing Pros Ltd | Other services | 2024 |
| Arborchase Limited | Agriculture & fishing | 2017 |
| Arch Contract Services Ltd | Construction | 2023 |
| Archer Construction Services Limited | Professional & scientific | 2007 |
| Architectural Industrial Refurbishment Limited | Construction | 2014 |
| Ariyah Children’S Care Ltd | Health & social care | 2024 |
| Arkitecht Creative Agency Limited | Professional & scientific | 2026 |