| Ashtons Manufacturing Limited | Wholesale & retail | 1997 |
| Ashwell Holdings Limited | Construction | 2015 |
| Ashwood Gate Management Company Limited | Households | 2006 |
| ASI Doors Limited | Manufacturing | 2011 |
| ASI Media Ltd | Professional & scientific | 2012 |
| ASI TEK Ltd | Hospitality | 2022 |
| Asil Barnsley Ltd | Hospitality | 2019 |
| ASK Renewables Holdings Ltd | Financial services | 2022 |
| ASK Renewables Limited | Construction | 2013 |
| ASK Renewables Property Ltd | Real estate | 2023 |
| Askd Holdings Limited | Financial services | 2024 |
| Askey Property Group Ltd | Real estate | 2024 |
| ASL Electrical Contractors Ltd | Construction | 2016 |
| ASM Delivery Ltd | Wholesale & retail | 2017 |
| Asmus Limited | Health & social care | 2018 |
| Aspect Sport CIC | Education | 2019 |
| Aspinwall Roofing Limited | Construction | 2022 |
| Aspire Fabrications Ltd | Manufacturing | 2018 |
| Aspire Furniture Limited | Wholesale & retail | 2013 |
| Aspire in the Community Ltd | Health & social care | 2009 |
| Aspire in the Community Services Ltd | Health & social care | 2011 |
| Aspire Manufacturing Limited | Manufacturing | 2016 |
| Aspire Taekwondo Ltd | Arts & recreation | 2020 |
| ASPIRE2B Community Interest Company | Administrative & support | 2012 |
| Asquith & Higham Ltd | Real estate | 2022 |
| Asquith & Mckeefery Limited | Information & communication | 2015 |
| Asquith Site Services Ltd | Construction | 2007 |
| Asquiths Roofing and Construction Ltd | Construction | 2024 |
| Assemble Brickwork & Maintenance Ltd | Construction | 2022 |
| Assessment & Training Nerac Limited | Education | 2006 |
| Asset Holdings Ltd | Financial services | 2026 |
| Assistive Technology Solutions Ltd | Health & social care | 2025 |
| Associated Hospitality Ltd | Administrative & support | 2011 |
| Association of Metropolitan Authorities (Properties) Limited | Real estate | 1961 |
| Assured Access Solutions Yorkshire Ltd | Administrative & support | 2025 |
| Assured Care Cover Ltd | Other services | 2019 |
| Astrix Golf Limited | Manufacturing | 2024 |
| ASW Engineering Services Ltd. | Wholesale & retail | 2016 |
| Asya Food Ltd | Hospitality | 2025 |
| AT Focused Solutions Limited | Professional & scientific | 2015 |
| ATD Fabs Ltd | Manufacturing | 2011 |
| ATD Property Developments Ltd | Real estate | 2025 |
| ATE Fabrication & Welding Ltd | Manufacturing | 2018 |
| Atelier 33 Limited | Arts & recreation | 2025 |
| Athena Manufacturing Limited | Manufacturing | 2014 |
| Athersley Commercial Ltd. | Construction | 2010 |
| ATHERSLEYRECFC26 Limited | Arts & recreation | 2026 |
| ATJ Property Developments Ltd | Real estate | 2026 |
| Atkinson Building Consultancy Ltd | Professional & scientific | 2018 |
| Atlantic Fisheries Barnsley Ltd | Hospitality | 2026 |
| Atlas & I Ltd | Manufacturing | 2013 |
| Atlas & Trident Limited | Professional & scientific | 2017 |
| Atlas Chiropractic Clinic Ltd. | Health & social care | 2007 |
| Atlas Development Estate Ltd | Real estate | 2025 |
| Atlas Retailers Ltd | Wholesale & retail | 2022 |
| ATM Family Ltd | Wholesale & retail | 2024 |
| Atolia Innovations Ltd | Financial services | 2024 |
| Atom & IVY Studio Ltd | Other services | 2026 |
| Atom Transport Ltd | Transport & logistics | 2022 |
| ATR Flooring Services Limited | Construction | 2015 |
| Atrament Limited | Professional & scientific | 2007 |
| Atrium Court Restaurant Limited | Real estate | 2010 |
| ATS Motorsport Limited | Arts & recreation | 2024 |
| ATT Food Ltd | Hospitality | 2019 |
| Atta Homes Limited | Construction | 2014 |
| Atta Properties Limited | Construction | 2013 |
| Atulit.Frankies Ltd | Hospitality | 2025 |
| Audiotech Services Limited | Administrative & support | 1998 |
| Aughnafosker Productions Ltd | Information & communication | 2019 |
| Aurae Collective Ltd | Wholesale & retail | 2024 |
| Auralis Homes Limited | Construction | 2025 |
| Aurelius Marvel Holding Limited | Financial services | 2021 |
| Aurelius Marvel One Limited | Financial services | 2021 |
| Aurelius Marvel Two Limited | Financial services | 2021 |
| Aureum Performance Ltd | Arts & recreation | 2023 |
| Aurora Beauty Aesthetics Ltd | Health & social care | 2026 |
| Austwick Brickmason Limited | Construction | 2025 |
| Autentico (Hoyland) Limited | Hospitality | 2024 |
| Authenance Limited | Information & communication | 2025 |
| Autism Support & Care Limited | Health & social care | 2007 |
| Auto Body Solutions Ltd | Wholesale & retail | 2026 |
| Auto Door Control Ltd | Other services | 2024 |
| Auto-Moto Trans Ltd | Wholesale & retail | 2021 |
| Autographic Creative Ltd | Other services | 2024 |
| Autokraft VW Ltd | Wholesale & retail | 2015 |
| Automated Accountancy Limited | Professional & scientific | 2021 |
| Automated Gate Fabrications Ltd | Manufacturing | 2020 |
| Automation Training Limited | Education | 2024 |
| Autopartner Pro Limited | Professional & scientific | 2024 |
| Avacorn Ltd | Transport & logistics | 2025 |
| Avalon Construction & Civil Engineering Limited | Wholesale & retail | 2006 |
| Avant Consultants Limited | Information & communication | 2019 |
| AVB Franchises Limited | Hospitality | 2025 |
| Avedi Commerce Limited | Wholesale & retail | 2026 |
| Avedi Solutions Ltd | Construction | 2017 |
| Averne Homes Ltd | Construction | 2025 |
| Avey Lets Ltd | Real estate | 2026 |
| Avfonit Online Ltd | Wholesale & retail | 2022 |
| Avivanoctis Ltd | Transport & logistics | 2025 |
| AVJ Investments Ltd | Transport & logistics | 2016 |