| AEX International Ltd | Information & communication | 2025 |
| AF Aviation & Maintenance Limited | Manufacturing | 1997 |
| AF Housing Ltd | Real estate | 2018 |
| Affinity Homecare Group Ltd | Health & social care | 2011 |
| Affinity Investment Holdings Ltd | Households | 2021 |
| Aftongreen Retail Limited | Real estate | 1993 |
| Agamia Ltd | Health & social care | 2023 |
| AGE of Stars Limited | Information & communication | 2026 |
| Agenor Management Services Limited | Real estate | 2013 |
| Agentis Capital Advisors UK Limited | Professional & scientific | 2022 |
| AGG Associates Ltd | Information & communication | 2013 |
| Aggregated Platform Solutions Limited | Information & communication | 2019 |
| Agile Cleaning Services Ltd | Administrative & support | 2020 |
| Agnew Equestrian Limited | Agriculture & fishing | 2022 |
| Agricultural Steel Limited | Agriculture & fishing | 2019 |
| Aguler Ltd | Administrative & support | 2022 |
| Ahid Abood Plastic Surgery Limited | Health & social care | 2015 |
| Ahmeds Wilmslow Ltd | Real estate | 2017 |
| Ahrc Limited | Real estate | 2018 |
| AI Byte Ltd | Information & communication | 2026 |
| AI Ivanco Ltd | Professional & scientific | 2025 |
| AI Management Consultants Ltd | Information & communication | 2026 |
| AIC Associates Limited | Administrative & support | 2011 |
| Aidan Fitzgerald Ltd | Health & social care | 2013 |
| Aintshar Ltd | Hospitality | 2022 |
| Air ADS Limited | Transport & logistics | 1999 |
| Air VIP Services Limited | Transport & logistics | 2025 |
| Airport Solutions Ltd | Professional & scientific | 2004 |
| Aisling Plastic Surgery Limited | Health & social care | 2015 |
| Aisma Limited | Professional & scientific | 2000 |
| Aivana Limited | Professional & scientific | 2023 |
| AJ Bowker Investments Ltd | Professional & scientific | 2023 |
| AJ Brickslip & Tiling Co Ltd | Construction | 2025 |
| AJ Dentistry Limited | Health & social care | 2021 |
| AJ Medicare Limited | Health & social care | 2018 |
| AJ Real Estate Holdings Limited | Real estate | 2023 |
| AJ Wigham Medical Ltd | Health & social care | 2022 |
| AJ Windle Consulting Limited | Information & communication | 2014 |
| AJB GUT Health Limited | Health & social care | 2019 |
| AJB Investment Holdings Limited | Financial services | 2022 |
| Ajcb Limited | Health & social care | 2018 |
| AJK PM Ltd | Real estate | 2024 |
| AJP Imaging Limited | Health & social care | 2024 |
| Ajsa Consultancy Limited | Administrative & support | 2022 |
| AJW Investments 2023 Limited | Financial services | 2023 |
| AK Electrical Solutions Ltd | Construction | 2021 |
| AK Property SPV Ltd | Real estate | 2026 |
| AK Psychiatry Ltd | Health & social care | 2021 |
| AK4 Property Ltd | Real estate | 2024 |
| Akak Holdings Limited | Financial services | 2025 |
| Akenori Labs Ltd | Information & communication | 2025 |
| Akiboye Investments Ltd | Health & social care | 2022 |
| Akora Properties Ltd | Real estate | 2019 |
| AKR Care Homes Limited | Health & social care | 2017 |
| AKR Care Homes Properties Limited | Health & social care | 2017 |
| Akrs Carehomes Limited | Health & social care | 2019 |
| AKS Consulting Limited | Professional & scientific | 2015 |
| AL Sihiya Limited | Public administration | 2025 |
| Al-Hatimy Properties Ltd | Real estate | 2019 |
| Al-Hatimy Properties Newco Ltd | Real estate | 2022 |
| Alamdc Ltd | Professional & scientific | 2024 |
| Alan Douglas Aviation Ltd | Professional & scientific | 2022 |
| Alan Douglas Properties Ltd | Real estate | 2023 |
| Alan Glen Wilson Limited | Health & social care | 2012 |
| Alanclarkdesign Limited | Information & communication | 2024 |
| Alaska Projects Limited | Administrative & support | 2007 |
| Albert R. Slack Limited | Other services | 1970 |
| ALC Financial Consulting Ltd | Professional & scientific | 2024 |
| Alchemy Fabrics Ltd | Extraterritorial | 2023 |
| Alconbury Apartments (Parcels 9 & 10A) Management Company Limited | Households | 2024 |
| Alcor Reliance Ltd | Professional & scientific | 2019 |
| Aldbury Developments Limited | Real estate | 1999 |
| Alderley Edge (Cheshire) Holdings Limited | Construction | 2026 |
| Alderley Edge Cricket Club Limited | Professional & scientific | 1960 |
| Alderley Edge Hockey Club Ltd | Extraterritorial | 2013 |
| Alderley Edge Squash Club Limited | Extraterritorial | 2014 |
| Alderley Edge Strategic Developments Limited | Professional & scientific | 2026 |
| Alderley Edge Tennis Club Limited | Extraterritorial | 2014 |
| Alderley Football Coaching Limited | Education | 2022 |
| Alderley Garden Services Limited | Administrative & support | 2015 |
| Alderley Mowers & Machinery Ltd | Manufacturing | 2004 |
| Aled Jones Building Ltd | Construction | 2018 |
| Aletho Dental Care Ltd | Health & social care | 2022 |
| Aletho Property Limited | Real estate | 2026 |
| Aleva Holdings Limited | Financial services | 2019 |
| Alex Mills Digital Limited | Professional & scientific | 2020 |
| Alexander James Bathrooms Ltd | Wholesale & retail | 2020 |
| Alexis Cole Limited | Other services | 2008 |
| Alfaros Jewellery Ltd | Wholesale & retail | 2019 |
| Alfix Scaffolding Ltd | Construction | 2020 |
| Algaplex Limited | Professional & scientific | 2014 |
| Alice Align Consulting Services Ltd | Professional & scientific | 2025 |
| Align Real Estate Ltd | Real estate | 2023 |
| Aligned Inclusion Consulting Ltd | Education | 2025 |
| Aljac Welding Services Co. Ltd. | Construction | 2023 |
| ALK Medical and Dental Services Ltd | Health & social care | 2023 |
| Alkane Investments Ltd | Financial services | 2019 |
| Alkane Solutions Ltd | Information & communication | 2011 |
| ALL Matters Financial Limited | Professional & scientific | 2015 |
| ALL1 Operations Limited | Professional & scientific | 2019 |