| ALI and Chap Ltd | Information & communication | 2018 |
| Alices Tea Shop Ltd | Hospitality | 2022 |
| Aligned Psychology Ltd | Education | 2025 |
| ALL Seasons Tree Care (East Midlands) Limited | Administrative & support | 2022 |
| Allez! Bakes Limited | Manufacturing | 2023 |
| Allis Vending Co. Ltd | Wholesale & retail | 2025 |
| Allsopp Detailing Limited | Professional & scientific | 2016 |
| Alpha Bravo Charlie Storage Ltd | Transport & logistics | 2026 |
| Alpha Flue Services Ltd | Construction | 2017 |
| Alpha Products UK Limited | Wholesale & retail | 2019 |
| Alphi Limited | Hospitality | 2006 |
| AM Performance Solutions Ltd | Other services | 2025 |
| AM Pizza and Kebabs Limited | Hospitality | 2026 |
| AM Valeting & Detailing Ltd | Other services | 2026 |
| Amara Made Limited | Wholesale & retail | 2024 |
| Amba Consulting (UK) Limited | Professional & scientific | 2011 |
| Amba Design and Build Limited | Construction | 2017 |
| Amhurst Homes Ltd | Real estate | 2021 |
| Amorethand Limited | Professional & scientific | 2009 |
| Amorin Ward Associates Limited | Professional & scientific | 2008 |
| Ampm Exterior Limited | Construction | 2017 |
| Amreco Limited | Real estate | 2001 |
| AMT Aircraft Engineering and Property Investments Limited | Professional & scientific | 2022 |
| AMY Walker Consulting Ltd | Professional & scientific | 2020 |
| AMZ Design Ltd | Professional & scientific | 2025 |
| Anam Pharma Ltd | Professional & scientific | 2012 |
| Anchor Global Partners Ltd | Wholesale & retail | 2026 |
| Ancient Tree Nursery CIC | Agriculture & fishing | 2025 |
| Andersons the Farm Business Consultants Limited | Administrative & support | 2001 |
| Andrew James Carpentry Limited | Extraterritorial | 2021 |
| Andrew Sibree Consulting Limited | Professional & scientific | 2013 |
| Andrew Taylor Plumbing & Heating Limited | Construction | 2014 |
| Anglo Adhesives & Services Limited | Manufacturing | 1999 |
| Ankle Hill Management Company Limited | Extraterritorial | 2017 |
| Anna Jeffreys Limited | Professional & scientific | 2010 |
| Anna Munton Ltd | Professional & scientific | 2025 |
| Anne Clark Consulting Limited | Administrative & support | 2009 |
| Annie Wright Chiropractic Limited | Health & social care | 2011 |
| Annotech Service Ltd | Administrative & support | 2020 |
| Ansirac Limited | Hospitality | 2023 |
| Antalya Group Ltd | Hospitality | 2023 |
| Anthemion Software Limited | Information & communication | 2003 |
| Anthony Hancock Limited | Real estate | 2007 |
| Anthony Peters Manufacturing Company Limited | Manufacturing | 1997 |
| AOS Products Limited | Wholesale & retail | 2012 |
| AP Group Services Ltd | Wholesale & retail | 2018 |
| AP Group Solutions Ltd | Wholesale & retail | 2018 |
| AP Imports Limited | Wholesale & retail | 2015 |
| AP Roofing Specialists Limited | Construction | 2025 |
| APC Barriers Limited | Construction | 2022 |
| Apex Building Services (Melton Mowbray) Ltd | Construction | 2018 |
| Apex Finishing Solutions Ltd | Transport & logistics | 2023 |
| Apex Projects (East Midlands) Ltd | Professional & scientific | 2026 |
| Approved Fire Protection Limited | Manufacturing | 1994 |
| Apricot Management Limited | Professional & scientific | 2014 |
| Aquarius Plumbing (Melton Mowbray) Limited | Households | 2010 |
| Aquaseed Ltd | Administrative & support | 2026 |
| Aquini Pubs Ltd | Hospitality | 2024 |
| Arborway Ltd | Professional & scientific | 2022 |
| ARC Design Engineering Limited | Professional & scientific | 2012 |
| ARC Roofing & Construction Limited | Construction | 2023 |
| Archer Stone Ltd | Administrative & support | 2025 |
| Archie Ross Property Investments Limited | Real estate | 2013 |
| Archipelago Learning Holdings UK Limited | Information & communication | 2010 |
| Aril Construction Ltd | Construction | 2019 |
| Ariyan & Sons Limited | Hospitality | 2018 |
| Armatus Canine Limited | Administrative & support | 2014 |
| Armatus Canine Training and Behaviour Ltd | Education | 2024 |
| Arthij UK Limited | Wholesale & retail | 2025 |
| Artis Interim Management Limited | Professional & scientific | 2010 |
| Artspod Limited | Information & communication | 2015 |
| Aryan and GIN Ltd | Administrative & support | 2016 |
| Ascension Fitness Ltd | Arts & recreation | 2026 |
| ASD Advisory Ltd | Public administration | 2025 |
| Asfordby Chippy Limited | Hospitality | 2019 |
| Asfordby Football Club Limited | Hospitality | 2013 |
| Asfordby Hill Primary School | Education | 2013 |
| Asfordby News & Convenience Ltd | Wholesale & retail | 2025 |
| Asfordby Property Company Ltd | Real estate | 2026 |
| Asheville Interior Design Ltd | Professional & scientific | 2024 |
| Ashley Hamilton Dance Company Ltd | Arts & recreation | 2025 |
| Ashmore Contracting Limited | Construction | 2014 |
| Ashwell Self Storage Ltd | Administrative & support | 2019 |
| ASK George Ltd | Information & communication | 2024 |
| Aspire HR & Training Consultants Limited | Administrative & support | 2025 |
| ASSESS2 Ltd | Health & social care | 2025 |
| Assets Global Limited | Professional & scientific | 2001 |
| Associate 2 Innovate Limited | Professional & scientific | 2006 |
| Astar Pipa Testing & Sales Ltd | Wholesale & retail | 2024 |
| ATE International Ltd | Manufacturing | 2012 |
| ATF Drainage Ltd | Water & waste | 2024 |
| Atlas Intercontinental Logistics Limited | Transport & logistics | 2013 |
| ATT Homes Ltd | Real estate | 2020 |
| Atterbury Payne Limited | Professional & scientific | 2020 |
| Attractions and Heritage Consultancy Limited | Other services | 2010 |
| Audio Focus Limited | Wholesale & retail | 2021 |
| Austin Medical Products Limited | Wholesale & retail | 2013 |
| Automated Spaces Ltd | Information & communication | 2016 |
| Autumn Property Solutions Limited | Construction | 2010 |
| AV Marketing Ltd | Wholesale & retail | 2019 |