| Allybeth Limited | Professional & scientific | 2015 |
| Alphabond (Holdings) Limited | Professional & scientific | 2014 |
| Alphabond Technologies Limited | Manufacturing | 2014 |
| Alpine Advisory Limited | Administrative & support | 2017 |
| Altec Consultancy Limited | Real estate | 2012 |
| Alternative Primeur Group Ltd. | Financial services | 2014 |
| Aluminium Doors Direct Ltd | Construction | 2022 |
| Aluminium Fencing Panels Limited | Manufacturing | 2014 |
| Alvanley Arms (Cotebrook) Ltd | Hospitality | 2026 |
| Alwaysverify Ltd | Information & communication | 2025 |
| Alyve Limited | Information & communication | 2010 |
| AM Coyle Avionics Ltd | Professional & scientific | 2016 |
| AM Fixing Ltd | Construction | 2026 |
| Amateur Athletic Association Limited | Arts & recreation | 1948 |
| Ambient Property Limited | Real estate | 2016 |
| AMD Group Ltd | Transport & logistics | 2016 |
| Ameliore Skincare Ltd | Wholesale & retail | 2022 |
| AMI Farms Limited | Agriculture & fishing | 2000 |
| AML Leisure Management Limited | Hospitality | 2014 |
| Amoove Limited | Administrative & support | 2025 |
| AMR Technical Ltd | Construction | 2020 |
| Amrock Property Ltd | Real estate | 2017 |
| Amrock Property [B] Ltd | Real estate | 2025 |
| Analog and Vintage Studio Ltd | Information & communication | 2026 |
| Anbucomay Design Limited | Professional & scientific | 2025 |
| Andartos Limited | Information & communication | 2024 |
| Anderson Aspects Limited | Construction | 2022 |
| Anderson Bevan Limited | Real estate | 1997 |
| Anderson Products Limited | Manufacturing | 2020 |
| Anderton Holdings Limited | Real estate | 2002 |
| Anderton MOT Centre Limited | Wholesale & retail | 2012 |
| Andrew Bloomer Associates Limited | Administrative & support | 2003 |
| Andrew L Curran Ltd | Health & social care | 2016 |
| Andrew Tomenson Consulting Ltd | Professional & scientific | 2026 |
| Andud Solutions Limited | Professional & scientific | 2018 |
| Andy MAY Angling Ltd | Other services | 2024 |
| Angel Book Publishing Limited | Information & communication | 2023 |
| Angela Westington Consulting Limited | Education | 2017 |
| Angove Private Capital Ltd | Professional & scientific | 2026 |
| Animal Medics UK Limited | Professional & scientific | 2001 |
| Aniston Bay Editorial Ltd | Professional & scientific | 2023 |
| ANN Lucas Consultancy Limited | Professional & scientific | 2022 |
| Anqr Group Ltd | Real estate | 2026 |
| Anthony Hitchiner Ltd | Professional & scientific | 2015 |
| Anthos Communications Limited | Professional & scientific | 2019 |
| Anvil Consulting (North West) Limited | Professional & scientific | 2001 |
| Anyan Consulting Limited | Financial services | 2015 |
| AOD Investments Limited | Financial services | 2016 |
| Aopoland Ltd | Transport & logistics | 2020 |
| AP Autopaint Ltd | Wholesale & retail | 2021 |
| AP Hawes Consultancy Limited | Professional & scientific | 2024 |
| Apex Plumbing, Heating & Mechanical Services Ltd | Construction | 2025 |
| Apex SIM Tracker Ltd | Arts & recreation | 2025 |
| APL Health Limited | Health & social care | 2015 |
| Aplify Ltd | Information & communication | 2026 |
| Apollyon Limited | Administrative & support | 2006 |
| Aporetica Limited | Information & communication | 2025 |
| Appero Studio Limited | Information & communication | 2026 |
| Appian Financial Services Limited | Financial services | 2003 |
| Appian Group Limited | Financial services | 2002 |
| Apple Best Care Ltd | Health & social care | 2020 |
| Appleton Potato Mart Limited | Health & social care | 1987 |
| Appliance Installations Limited | Construction | 2007 |
| Applique Music Ltd | Wholesale & retail | 2021 |
| Apricot Blue Catering Ltd | Hospitality | 2021 |
| Apricot Blue Ltd | Hospitality | 2023 |
| April Goodier Ltd | Agriculture & fishing | 2013 |
| Apsleygrange Limited | Real estate | 1983 |
| APW (Cheshire) Consulting Ltd | Professional & scientific | 2023 |
| Aquatect Ltd | Administrative & support | 2008 |
| Aquatics MAD Ltd | Wholesale & retail | 2021 |
| Aquel Projects Limited | Extraterritorial | 2016 |
| Aquidian Limited | Professional & scientific | 2022 |
| Arakle Limited | Information & communication | 2022 |
| ARC 360 Ltd | Professional & scientific | 2023 |
| Arch Brokerage Ltd | Financial services | 2025 |
| Archi-Scape Ltd | Professional & scientific | 2020 |
| Arclid Property Ltd | Real estate | 2024 |
| Arclid.Com Limited | Information & communication | 2001 |
| Ardglass Property Ltd | Construction | 2018 |
| Areya Investment Ltd | Real estate | 2024 |
| Arian Mixed Farming Ltd | Agriculture & fishing | 2024 |
| Aribella Catering Solutions Limited | Hospitality | 2018 |
| Arkk Studios Ltd | Wholesale & retail | 2026 |
| Arley Moss Equestrian Limited | Administrative & support | 2010 |
| Armada Insights Limited | Administrative & support | 2025 |
| Armadillo Global Limited | Administrative & support | 2024 |
| Arrowtac Ltd | Manufacturing | 2007 |
| Artisan Bathrooms Limited | Construction | 2002 |
| Arts ADD Vantage Ltd | Wholesale & retail | 2024 |
| Aruna RAJ Company Limited | Health & social care | 2014 |
| Aruna RAJ Real Estate Limited | Real estate | 2026 |
| Arvox Ltd | Wholesale & retail | 2024 |
| AS Energy Services Limited | Professional & scientific | 2020 |
| AS the Crow Flies Limited | Professional & scientific | 2023 |
| Asepta Limited | Professional & scientific | 2012 |
| Asepta Properties Ltd | Real estate | 2021 |
| ASH House Car Sales Ltd | Wholesale & retail | 2020 |
| ASH House Property Management Limited | Real estate | 2022 |
| Ashby Lodge Residents Management Company Limited | Households | 2013 |