| A P Tree Contractors Limited | Administrative & support | 2020 |
| A P Tree Services Limited | Administrative & support | 2024 |
| A Plant Limited | Construction | 2026 |
| A R Facilities Limited | Administrative & support | 2026 |
| A R Miles Associates Limited | Professional & scientific | 2018 |
| A S Logie Services Limited | Professional & scientific | 2019 |
| A to Z Morrisseyco Ltd | Financial services | 2022 |
| A Touch of Glass Warwickshire Ltd | Construction | 2016 |
| A Turpin Limited | Professional & scientific | 2013 |
| A Way to Store Limited | Professional & scientific | 2004 |
| A&D Cleaning (Midlands) Limited | Administrative & support | 2025 |
| A&H Jones & Co. Limited | Manufacturing | 2015 |
| A&J Financial Services Ltd | Financial services | 2022 |
| A&M Cleaning Ltd | Administrative & support | 2019 |
| A&M Lifestyle Ltd | Wholesale & retail | 2024 |
| A&S Claims Management Limited | Professional & scientific | 2012 |
| A&Z Ventures Ltd | Health & social care | 2024 |
| A-Star Security Solutions Ltd | Administrative & support | 2025 |
| A.I.D Investments Ltd | Professional & scientific | 2011 |
| A.J. Lloyd Holdings Limited | Financial services | 2016 |
| A.S.M. Print Ltd | Wholesale & retail | 2021 |
| A1 Express Limited | Transport & logistics | 2018 |
| A1 JET Ltd | Wholesale & retail | 2023 |
| A1BA JJ Warwick Limited | Arts & recreation | 2026 |
| A1BA JJ Worcester Ltd | Arts & recreation | 2026 |
| A2BEE Chair Hire Limited | Extraterritorial | 2008 |
| AAA Digital Hub Ltd | Wholesale & retail | 2024 |
| AAE Assets Ltd | Extraterritorial | 2020 |
| AAP Ltd | Wholesale & retail | 2019 |
| AAR TEE Ferretti International Holdings Ltd | Financial services | 2018 |
| AAR TEE Industries Holdings UK Ltd | Financial services | 2018 |
| Aasaka Limited | Administrative & support | 2019 |
| AB Digital Media Limited | Information & communication | 2023 |
| AB1 Commercial Developments Limited | Construction | 2022 |
| Abacus Offgrid Ltd | Construction | 2013 |
| Abacus Solar Systems Ltd | Construction | 2013 |
| Abarella Limited | Real estate | 2018 |
| ABB Dale Limited | Real estate | 2019 |
| Abbey Wood Gardens Limited | Real estate | 2017 |
| Abbey Wood Hotels Ltd | Extraterritorial | 2026 |
| Abbey Wood Hotels Trading Ltd | Extraterritorial | 2026 |
| Abbey Wood Property 2 Ltd | Extraterritorial | 2026 |
| Abbey Wood Property 3 Ltd | Extraterritorial | 2026 |
| Abbey Wood Property Ltd | Real estate | 2016 |
| Abbotsford Mews Property Management Company Limited | Real estate | 2017 |
| Abell Geospatial Consulting Limited | Professional & scientific | 2015 |
| Abilitynet | Information & communication | 1997 |
| Ablaze Fire Protection Ltd | Administrative & support | 2019 |
| Abletex Limited | Construction | 2009 |
| Ablmobility Ltd | Professional & scientific | 2025 |
| Abode Construction (Rugby) Ltd | Construction | 2025 |
| Absolute Bargain Ltd | Extraterritorial | 2021 |
| AC Electrical and Property Services Ltd | Construction | 2025 |
| AC Electronics Ltd | Professional & scientific | 2017 |
| AC Equine Services Ltd | Wholesale & retail | 2021 |
| ACA Royal Leamington Spa Ltd | Construction | 2025 |
| Accenni Ltd | Professional & scientific | 2020 |
| Access to Acupuncture CIC | Education | 2025 |
| Accles and Pollock Limited | Manufacturing | 2015 |
| Accoundite Business Consultant Private Limited | Information & communication | 2024 |
| Accountemps Limited | Professional & scientific | 2010 |
| Accounting Guru Limited | Professional & scientific | 2025 |
| Accounts Payable Limited | Other services | 2014 |
| Acdw Limited | Agriculture & fishing | 2019 |
| Ace Global Solutions Limited | Professional & scientific | 2010 |
| Aceit Sportswear Ltd | Wholesale & retail | 2019 |
| Acer Beauty Ltd | Other services | 2024 |
| Acer Control Systems Ltd | Information & communication | 2006 |
| ACG Empire Ltd | Transport & logistics | 2024 |
| Achieve Trading Ltd | Education | 2019 |
| Achieving Results in Communities CIC | Administrative & support | 2011 |
| ACR Heating Solutions Ltd | Construction | 2012 |
| Acres Land Property Management Limited | Real estate | 2022 |
| ACT Care Support Limited | Public administration | 2022 |
| ACT Child Care Services Limited | Public administration | 2025 |
| ACT Education and Care Limited | Education | 2026 |
| ACT for Autism C.I.C. | Other services | 2018 |
| ACT Group Holdings Ltd | Financial services | 2024 |
| ACT on Consultancy Limited | Professional & scientific | 2023 |
| Action 21 (2010) | Wholesale & retail | 2010 |
| Acton Living Limited | Construction | 2026 |
| Actus Properties Limited | Real estate | 2018 |
| Acute Medical Care Limited | Health & social care | 2006 |
| Acutech Ltd | Professional & scientific | 2024 |
| ACW Motorsport Plastics Ltd | Manufacturing | 2014 |
| AD Grisdale Consulting Ltd | Information & communication | 2026 |
| Adam Brain Building Services Ltd | Construction | 2019 |
| Adams Legacy Holding Ltd | Real estate | 2023 |
| Adams Plumbing and Heating Maintenance Ltd | Construction | 2019 |
| Adams Strategic Consulting Limited | Professional & scientific | 2024 |
| Adbolton Limited | Professional & scientific | 2004 |
| Adderbury QS Services Limited | Professional & scientific | 2016 |
| Addex Construction & Consultancy Limited | Construction | 2018 |
| Adele Long Limited | Other services | 2015 |
| Adelphian Ltd | Professional & scientific | 2023 |
| Adembo Design & Engineering Limited | Professional & scientific | 2012 |
| Aden Investments Limited | Other services | 2011 |
| ADG QS Services Limited | Professional & scientific | 2014 |
| Adgen Holdings Limited | Administrative & support | 2015 |
| Adgen Limited | Administrative & support | 2011 |