| Alpha Metalwork Services Ltd | Manufacturing | 2023 |
| Alpha Omega Property Ltd | Real estate | 2020 |
| Alpha Property Solutions (Rotherham) Ltd | Construction | 2019 |
| Alpha Trading Ltd | Wholesale & retail | 2021 |
| Alpine Arborist Ltd | Administrative & support | 2024 |
| Alponce's Limited | Wholesale & retail | 2024 |
| Alpsavvy Ltd | Information & communication | 2019 |
| Alrac Services Ltd | Administrative & support | 2022 |
| Alsha Homes Limited | Health & social care | 2024 |
| ALT Haulage Limited | Transport & logistics | 2007 |
| Altairco (UK) Limited | Information & communication | 2024 |
| Altered Images Photography Limited | Professional & scientific | 2008 |
| Alternate Energy Supplies Limited | Energy | 2011 |
| Altmedia Limited | Information & communication | 2000 |
| Altru & Aspire Medical Ltd | Education | 2025 |
| Aluminium Gates Direct Ltd | Wholesale & retail | 2021 |
| Aluminium Gates Group Ltd | Wholesale & retail | 2023 |
| Aluvista UK Ltd | Manufacturing | 2025 |
| Alva Medical Ltd | Health & social care | 2022 |
| Alvi Island Technology Services Ltd | Information & communication | 2023 |
| Always Nineteen Ltd | Education | 2022 |
| AM Accounts Services Limited | Professional & scientific | 2016 |
| AM Performance Ltd | Professional & scientific | 2023 |
| AM Services NW Ltd | Wholesale & retail | 2019 |
| Amanda Computing Ltd | Wholesale & retail | 2026 |
| Amanda Shaw Property Developer Ltd | Real estate | 2025 |
| Amandas Blinds Limited | Wholesale & retail | 2010 |
| Amano Blick International (Europe) Limited | Extraterritorial | 1996 |
| Amaraservices Ltd | Wholesale & retail | 2025 |
| AMB Media Ltd | Information & communication | 2025 |
| Ambc Edelweiss Houses Limited | Real estate | 2025 |
| Amber Financial Solutions Limited | Financial services | 2025 |
| Amber Mini Market Limited | Wholesale & retail | 2025 |
| Amber Traffic Management Limited | Construction | 2019 |
| Amber Tyres Limited | Wholesale & retail | 2018 |
| Ambiance Greenhill Limited | Other services | 2019 |
| AMC Engineering Ltd | Manufacturing | 2019 |
| AMC Logistics Management Ltd | Professional & scientific | 2022 |
| AMD Complete Drywall Limited | Construction | 2021 |
| Amech Automotive Ltd | Manufacturing | 2025 |
| Amelia Transport Ltd | Transport & logistics | 2021 |
| Ameliorate Properties Ltd | Real estate | 2024 |
| Amethyst Care & Support Group Limited | Health & social care | 2020 |
| AMF Plastering Limited | Construction | 2016 |
| AMG Alpoco UK Limited | Manufacturing | 1969 |
| AMG Aluminum UK Limited | Manufacturing | 2012 |
| AMG Chrome Limited | Manufacturing | 1938 |
| AMG Property & Lettings Ltd | Real estate | 2026 |
| AMG UK Group Pension Trustee Limited | Professional & scientific | 2014 |
| Amiga HR Ltd | Administrative & support | 2025 |
| Amigos Thurnscoe Limited | Hospitality | 2024 |
| Amigos Yorkshire Limited | Hospitality | 2026 |
| Amijee Consultants Ltd | Professional & scientific | 2024 |
| Amijee Ltd | Real estate | 2020 |
| Aminth Energy Ltd | Energy | 2017 |
| Amman and Appan Ltd | Real estate | 2025 |
| AMN Sahota Limited | Health & social care | 2014 |
| AMP61 Limited | Transport & logistics | 2021 |
| Amplified Lashes Limited | Wholesale & retail | 2021 |
| AMR Auto Design Ltd | Wholesale & retail | 2017 |
| AMR Northern Limited | Financial services | 2019 |
| AMR Service and Maintenance Ltd | Manufacturing | 2018 |
| AMS Developments Ltd | Construction | 2026 |
| AMS Machinery and Rentals Limited | Wholesale & retail | 2024 |
| ANA Deac Ltd | Construction | 2023 |
| Anaesurgica Ltd | Health & social care | 2018 |
| Analityca Technologies Ltd | Information & communication | 2025 |
| Anastsis Ltd | Information & communication | 2014 |
| Anatolian Touch Ltd | Other services | 2025 |
| ANB Software Ltd | Information & communication | 2007 |
| Ancient Q Ltd | Wholesale & retail | 2022 |
| Ancona Consulting Limited | Information & communication | 2025 |
| Andania Engineering Limited | Professional & scientific | 2020 |
| Andbridge Projects Limited | Real estate | 2021 |
| Anderby Care Ltd | Health & social care | 2016 |
| Anderby Properties (SY) Limited | Real estate | 2021 |
| Andrea Investments Ltd | Real estate | 2023 |
| Andrei & Albert Ltd | Transport & logistics | 2016 |
| Andrew Rogers Wealth Management Limited | Financial services | 2014 |
| Andrew Sharp Mobile Motor Vehicle Technician Limited | Wholesale & retail | 2006 |
| Andrew Stacey Upvc Ltd | Construction | 2026 |
| Andrew William Lettings Ltd | Real estate | 2020 |
| Andrewgh Ltd | Transport & logistics | 2020 |
| Andrews & Lloyd Ltd | Professional & scientific | 2026 |
| Andrews Electrical Services Ltd | Construction | 2017 |
| Andrzej Mrugala Limited | Transport & logistics | 2015 |
| Andwis Lifts Limited | Professional & scientific | 1990 |
| Andy Candler Motor Engineers (2020) Ltd | Wholesale & retail | 2019 |
| Andy Pounder Cladding Services Ltd | Administrative & support | 2017 |
| Aneesa Locum Ltd | Wholesale & retail | 2025 |
| Angel Developments (Yorkshire) Limited | Administrative & support | 2007 |
| Angel Nails & Spa (Rotherham) Limited | Other services | 2025 |
| Angel Nook Limited | Health & social care | 2017 |
| Angelic Technology AI Ltd | Information & communication | 2025 |
| Angelicadbr Limited | Professional & scientific | 2019 |
| Angell Rental Properties Limited | Real estate | 2025 |
| Angels "Wrapp IT ALL" Limited | Wholesale & retail | 2019 |
| Angels Hair Salon Limited | Other services | 2022 |
| Angels Little Delights Ltd | Wholesale & retail | 2024 |
| Angie Green Energy Ltd | Wholesale & retail | 2024 |