| APS Redditch Ltd | Real estate | 2025 |
| APT Healthcare Limited | Health & social care | 2016 |
| Aquahelios Limited | Agriculture & fishing | 2017 |
| Aqualine Marine Limited | Manufacturing | 2002 |
| Aquaquip Limited | Administrative & support | 2019 |
| Aquarius Products Limited | Construction | 2012 |
| Aquatherapy Ltd | Manufacturing | 2026 |
| Aqueo Investments Limited | Administrative & support | 2008 |
| AR Convenience Limited | Wholesale & retail | 2019 |
| Araana Limited | Other services | 2019 |
| Arabella Homes Limited | Real estate | 2013 |
| Arbuthnot Medical Limited | Health & social care | 2012 |
| ARC Fabrication Services Limited | Manufacturing | 2026 |
| Arcadia Surveying & Management Ltd | Professional & scientific | 2020 |
| Arden Associates (IFA) LLP | | 2001 |
| Arden James Associates Limited | Administrative & support | 2020 |
| Ardimages UK Limited | Information & communication | 2015 |
| Arena Online Limited | Wholesale & retail | 2008 |
| Arenosa Holdings Limited | Financial services | 2016 |
| Aria Rose Revell Ltd | Extraterritorial | 2025 |
| Arif and Ricky Ltd | Arts & recreation | 2023 |
| Ariya Arts Ltd | Arts & recreation | 2020 |
| ARK Bloom Limited | Real estate | 2018 |
| Arley Management Limited | Administrative & support | 2018 |
| Arlington Property Developments Limited | Administrative & support | 2018 |
| Arlo Forrest Cleaning Services Ltd | Administrative & support | 2025 |
| Arnold Road Convenience Limited | Wholesale & retail | 2020 |
| Arova Property Ltd | Real estate | 2025 |
| Arrested Records Limited | Information & communication | 2011 |
| Arrivista Limited | Administrative & support | 2003 |
| Art of Chiropractic Limited | Health & social care | 2017 |
| Artisan Joinery Worcester Limited | Construction | 2016 |
| Artizan Roofing Limited | Construction | 2010 |
| Arto Property Maintenance Limited | Construction | 2021 |
| As-Dermatology Ltd | Health & social care | 2022 |
| Asap Fire Systems Limited | Construction | 2009 |
| ASB Defence Consulting Ltd | Professional & scientific | 2022 |
| ASB Homes Limited | Administrative & support | 2020 |
| ASB Land Development Limited | Administrative & support | 2017 |
| Ascent Series Ltd | Administrative & support | 2026 |
| Asdfx Labs Limited | Information & communication | 2025 |
| ASH Lane Property Developments Limited | Construction | 2022 |
| ASH Lane Property Management Limited | Real estate | 2023 |
| Asha LDN Ltd | Wholesale & retail | 2023 |
| Ashford Hospitality Ltd | Hospitality | 2025 |
| Ashford Neath Recruitment Ltd | Administrative & support | 2020 |
| Ashton & Moore Holdings Limited | Administrative & support | 2010 |
| Ashtreemews Limited | Real estate | 2008 |
| ASJ Galaxy Limited | Professional & scientific | 2024 |
| ASK Chemicals UK Ltd | Wholesale & retail | 2010 |
| ASM Access Ltd | Manufacturing | 2009 |
| ASN Enterprises Limited | Professional & scientific | 2022 |
| Asone Global Limited | Administrative & support | 2016 |
| Asone Limited | Information & communication | 2008 |
| Asper Property (Earlswood) Limited | Real estate | 2022 |
| Asper Property (Malvern) Limited | Real estate | 2026 |
| Asper Property (Stourbridge) Limited | Real estate | 2023 |
| Asper Property (Wombourne) Limited | Real estate | 2025 |
| Asper Property Group Limited | Real estate | 2019 |
| Asper Property Limited | Real estate | 2016 |
| Asper Residential Holdings Limited | Real estate | 2025 |
| Asplands Limited | Construction | 2024 |
| Assured Global Group Limited | Professional & scientific | 2021 |
| Assured Global Imports Limited | Wholesale & retail | 2021 |
| Astini Limited | Extraterritorial | 2012 |
| Astley Towne Estates Limited | Construction | 2002 |
| Aston Display Limited | Manufacturing | 1983 |
| Atalanta Motor Cars Limited | Manufacturing | 2009 |
| Athena Group Holdings Limited | Administrative & support | 2012 |
| Athena Worksurface Fabrications Ltd | Manufacturing | 2014 |
| Athletic Thinking Limited | Professional & scientific | 2017 |
| Atticus KIM Ltd | Arts & recreation | 2023 |
| Attillo Limited | Agriculture & fishing | 1987 |
| Auremanea Ltd | Administrative & support | 2021 |
| Austin & Rose Property Ltd | Real estate | 2025 |
| Authentic Inspirations CIC | Education | 2022 |
| Auto Lock Specialist Limited | Administrative & support | 2017 |
| Autocar Services (Droitwich Spa) Limited | Wholesale & retail | 2025 |
| Automation Controls Group Limited | Professional & scientific | 2026 |
| Automation Controls Limited | Professional & scientific | 2020 |
| Avant Academy Limited | Professional & scientific | 2022 |
| Avant Design Limited | Professional & scientific | 2023 |
| Avant Industrial Design Limited | Professional & scientific | 2018 |
| Avidity Consulting Limited | Professional & scientific | 2019 |
| Avkedtech Ltd | Wholesale & retail | 2026 |
| Avon Court Management (Evesham) Limited | Households | 2021 |
| Avon View Marina Limited | Transport & logistics | 2018 |
| AW Training Solutions Limited | Administrative & support | 2015 |
| Awaken Minds Limited | Health & social care | 2021 |
| AWC Homes Abroad Limited | Real estate | 2002 |
| AWS 1 Contracts Limited | Wholesale & retail | 2009 |
| AWT Holdings Ltd | Professional & scientific | 2015 |
| Axolotl Consulting Limited | Health & social care | 2017 |
| Aybee Clean Ltd | Administrative & support | 2023 |
| AZ Vasaanti Limited | Hospitality | 2023 |
| B Sure Property Lettings Ltd | Real estate | 2022 |
| B2 Electrical Ltd | Construction | 2022 |
| Babybase Limited | Wholesale & retail | 1980 |
| BAD Luck Tattoo Co Ltd | Arts & recreation | 2025 |
| Bagillt Ltd | Administrative & support | 2021 |