| ALL One Imagery Ltd | Arts & recreation | 2022 |
| ALL Seasons Window Cleaning Limited | Administrative & support | 2007 |
| ALL7 Group Holdings Ltd | Administrative & support | 2012 |
| ALL7 Ltd | Administrative & support | 1997 |
| Allos Holdings Limited | Manufacturing | 2016 |
| Alma Property Developments Limited | Real estate | 2002 |
| Almanac International Software Limited | Information & communication | 2026 |
| Alpha Beta Partners Limited | Financial services | 2017 |
| Alpha Beta Private Wealth Limited | Financial services | 2024 |
| Alpha Roof Specialists Ltd | Construction | 2023 |
| Alpine Court 2000 Limited | Households | 2000 |
| Alto Plano Limited | Administrative & support | 2011 |
| Altus Private Jets Ltd | Administrative & support | 2019 |
| Alveron Wine Merchants Ltd | Wholesale & retail | 2026 |
| Ambergris Interiors Ltd | Construction | 2021 |
| Ambiya Properties Ltd | Real estate | 2024 |
| Amck Consulting Limited | Professional & scientific | 2026 |
| Amjoja Ltd | Professional & scientific | 2022 |
| Amos Sport Ltd | Agriculture & fishing | 2018 |
| AMV Estates Ltd | Real estate | 2019 |
| AMX Direct Limited | Professional & scientific | 2010 |
| Anb-M Asset Management Ltd | Information & communication | 2024 |
| Ancaster Books Ltd | Arts & recreation | 2014 |
| Ancaster Lodge Residents Association Limited | Households | 1980 |
| Andrei's Art Company Limited | Administrative & support | 2013 |
| Andrew Carter Design Limited | Professional & scientific | 2021 |
| Andrew Hill Property Limited | Real estate | 2019 |
| Andrew Macdonald (London) Limited | Extraterritorial | 2006 |
| Andy Coughlin Consulting Limited | Education | 2011 |
| Angel IPL Limited | Other services | 2014 |
| Annie Bennett Academy Limited | Education | 2024 |
| ANS Developments Limited | Construction | 2018 |
| ANS Synergy Ltd | Other services | 2016 |
| Anthony-Richards Electronics Limited | Hospitality | 1968 |
| Anubis Earth Ltd | Health & social care | 2024 |
| Anyma Group Ltd | Wholesale & retail | 2025 |
| Anything Tows Ltd | Transport & logistics | 2025 |
| AP Financial Resourcing Ltd | Administrative & support | 2025 |
| Apex Accountancy Limited | Professional & scientific | 2025 |
| Apex Construction Systems Limited | Construction | 2025 |
| Apex Films Limited | Information & communication | 2010 |
| Apex Group Limited | Real estate | 2017 |
| Apex Panels Ltd | Construction | 2025 |
| Apextalentworks Ltd | Wholesale & retail | 2016 |
| APG Health Ltd | Health & social care | 2025 |
| Appleland Limited | Information & communication | 2009 |
| Arabian Peninsula Sports and Media Ltd | Arts & recreation | 2015 |
| Aranco Limited | Real estate | 2023 |
| ARB Plumbing and Heating Services Ltd | Construction | 2010 |
| Arbrix | Other services | 1999 |
| Arbrix Conferences Limited | Other services | 1999 |
| ARC Reset Ltd | Professional & scientific | 2026 |
| Archbury Ltd | Financial services | 2021 |
| Archer Court Management Company Limited | Households | 2002 |
| Architectural Activities Ltd | Professional & scientific | 2025 |
| Archtek Ltd | Professional & scientific | 2021 |
| Arctic Smiles Limited | Health & social care | 2016 |
| Arena Search & Selection Limited | Administrative & support | 2000 |
| Arise Talent Limited | Arts & recreation | 2025 |
| Armaxon Consultancy Ltd | Information & communication | 2012 |
| Armish Ltd | Real estate | 2024 |
| Armitage Murray Limited | Households | 1980 |
| Arpeggio Investment Group Ltd | Professional & scientific | 2025 |
| Arrow Lift Engineers Limited | Manufacturing | 1998 |
| ARS Consulting Group Ltd | Information & communication | 2018 |
| Artem Consultancy Limited | Construction | 2017 |
| Artis Studios Limited | Professional & scientific | 2007 |
| ASC UK Technologies Limited | Information & communication | 2004 |
| Ascolt Limited | Administrative & support | 2010 |
| Ascot Aesthetic Suite Limited | Health & social care | 2020 |
| Ascot Antique Clocks Ltd | Wholesale & retail | 2022 |
| Ascot Berks Ltd | Hospitality | 2023 |
| Ascot Bookkeeping & Accounting Ltd | Professional & scientific | 2017 |
| Ascot Butchers Ltd | Wholesale & retail | 2021 |
| Ascot Capital Ltd | Professional & scientific | 2019 |
| Ascot Capital Management LLP | | 2012 |
| Ascot Carpet Co Limited | Administrative & support | 2015 |
| Ascot Cars Ltd | Transport & logistics | 2014 |
| Ascot Commercial Ltd | Real estate | 2010 |
| Ascot Construct Ltd | Construction | 2025 |
| Ascot Contractors Ltd | Construction | 2021 |
| Ascot Design and Build Limited | Construction | 2021 |
| Ascot DRY Cleaners Limited | Other services | 2016 |
| Ascot EBT Ltd | Financial services | 2026 |
| Ascot Financial Solutions Ltd | Professional & scientific | 2025 |
| Ascot Fire Protection Limited | Wholesale & retail | 2015 |
| Ascot Foods Limited | Hospitality | 2020 |
| Ascot Garden Services Limited | Administrative & support | 2014 |
| Ascot Gardeners Ltd | Administrative & support | 2020 |
| Ascot Golden Lilly Limited | Hospitality | 2022 |
| Ascot Golf Limited | Administrative & support | 2010 |
| Ascot Health Practice Limited | Health & social care | 2017 |
| Ascot Hospitality Ltd | Hospitality | 2026 |
| Ascot Jewellery Club Ltd | Wholesale & retail | 2022 |
| Ascot Landscapes Limited | Administrative & support | 2025 |
| Ascot Life Church | Other services | 2010 |
| Ascot Management Consultancy Ltd | Professional & scientific | 2023 |
| Ascot Medical Aesthetics & Wellness Clinic Ltd | Health & social care | 2023 |
| Ascot Medispa Ltd | Other services | 2024 |
| Ascot Minimates Ltd | Arts & recreation | 2025 |