| Alma Road Residents Association Limited | Real estate | 1999 |
| Alpha Accountants Limited | Professional & scientific | 1997 |
| Alpha Engineering and Technical Services Limited | Other services | 1997 |
| Altair Associates Ltd | Real estate | 2008 |
| Alter Egos ET AL Limited | Administrative & support | 2007 |
| Alton Mortgages Limited | Financial services | 2005 |
| Altwood Business & Accountancy Services Limited | Professional & scientific | 2003 |
| Altwood Pharmacy Limited | Wholesale & retail | 2000 |
| Always Thinking Limited | Information & communication | 2005 |
| AM Systems ( Control Solutions ) Ltd | Information & communication | 2007 |
| Amazon World Limited | Extraterritorial | 1998 |
| Amirah Store Limited | Wholesale & retail | 2026 |
| Anay Enterprise Ltd | Other services | 2024 |
| Anchor House 75-77 White Hart Lane Limited | Professional & scientific | 1997 |
| Andromeda Consultants Limited | Extraterritorial | 2004 |
| Andy Crane Transport Limited | Transport & logistics | 1998 |
| Angband Software Services Limited | Information & communication | 1993 |
| Anglo Prodrive (Andover) Limited | Information & communication | 1994 |
| Animal Limited | Extraterritorial | 1987 |
| Animalsports Limited | Extraterritorial | 1994 |
| Anmol Web Limited | Information & communication | 2007 |
| Annver Ltd | Administrative & support | 2014 |
| Antex Technology Limited | Information & communication | 1998 |
| Anthony Curtis Estate Agents Limited | Real estate | 2004 |
| Anthony Travis Associates Limited | Other services | 2002 |
| Anytime Security UK Limited | Administrative & support | 2010 |
| AOK Yellow Ltd | Construction | 2004 |
| Apex Parking Limited | Other services | 2021 |
| Apocrypha Limited | Information & communication | 2006 |
| Apollo Cars of Ickenham Limited | Administrative & support | 2002 |
| Aquarius Plumbing & Heating (UK) Limited | Construction | 2005 |
| Aquatech (UK) Limited | Transport & logistics | 1970 |
| ARC Gateway Limited | Administrative & support | 1998 |
| Arcivant Solutions Limited | Information & communication | 2014 |
| Arimta Limited | Professional & scientific | 2012 |
| ARL Book-Keeping Services Limited | Professional & scientific | 2007 |
| Arrow Self Drive Limited | Administrative & support | 1999 |
| Art Directions Limited | Professional & scientific | 2003 |
| Art Reach [Consultants] Limited | Professional & scientific | 2002 |
| Arthur a Beaver Limited | Construction | 2002 |
| Artisan (Pre-Packs) Limited | Wholesale & retail | 1981 |
| Arzeen Properties Ltd | Real estate | 2017 |
| Asante Coffee Ltd | Hospitality | 2006 |
| Asap Computer Services Limited | Other services | 1989 |
| ASB Tax Services Limited | Professional & scientific | 2004 |
| Ascot Authority (Holdings) Limited | Arts & recreation | 2001 |
| Ascot Computer Consultancy Limited | Information & communication | 1997 |
| Ascot Racecourse Estates (Property Developments) Limited | Arts & recreation | 2001 |
| Ascot Racecourse Estates Limited | Arts & recreation | 2001 |
| Ascot Racecourse Limited | Arts & recreation | 2001 |
| Ascot Television and Video Limited | Manufacturing | 2002 |
| Asdesic Ltd | Information & communication | 2007 |
| Ashleigh House Developments Limited | Professional & scientific | 1991 |
| Aspen Belmont Limited | Health & social care | 2007 |
| Associated Biscuits | Transport & logistics | 1898 |
| ASW Marquees Limited | Administrative & support | 1998 |
| Atcore Technology Limited | Information & communication | 1999 |
| Ateb Consulting Limited | Professional & scientific | 2007 |
| Athene Solutions Limited | Information & communication | 2002 |
| Atlantic Bridge Limited | Professional & scientific | 1995 |
| Atom Recruitment Limited | Administrative & support | 2004 |
| Aundi Mason Catering Limited | Hospitality | 2008 |
| Auriema Ltd | Wholesale & retail | 2003 |
| Australian Wine Agencies Limited | Wholesale & retail | 1994 |
| Autoclaim Limited | Households | 1983 |
| Auxilium IT Limited | Information & communication | 2005 |
| AVC Impex Ltd | Wholesale & retail | 2025 |
| Avsmile Holding Ltd | Administrative & support | 2020 |
| Avspire Limited | Construction | 2006 |
| Axiom House | | 2000 |
| AYC Limited | Administrative & support | 2003 |
| Ayurveda Retreat Ltd | Health & social care | 2005 |
| B a Motor Care Ltd | Wholesale & retail | 2024 |
| B.& P.Macklin Limited | Manufacturing | 1965 |
| B.C.A. Landbase Limited | Agriculture & fishing | 1994 |
| BACK2BASICS Contractors Limited | Administrative & support | 2005 |
| Bailey Robinson Limited | Administrative & support | 1996 |
| Baileys Sunset Limited | Real estate | 1996 |
| Banfate Limited | | 1984 |
| Barling Invicta Holdings Limited | Professional & scientific | 1928 |
| Barnard Consulting Limited | Professional & scientific | 2002 |
| Barrens Park Residents Limited | Households | 1972 |
| Basingstoke Foods Ltd | Wholesale & retail | 2021 |
| Bath Road Flats Management Company Limited | Real estate | 1967 |
| Bay Cottons Limited | Wholesale & retail | 2005 |
| BCK Opticians Limited | Wholesale & retail | 2003 |
| BD Modeling Limited | Professional & scientific | 2022 |
| Beachcombers Limited | Other services | 2003 |
| Beacon Heating & Boiler Supplies Limited | Wholesale & retail | 2005 |
| Becton Dickinson UK Financing I Limited | Financial services | 2020 |
| Becton Dickinson UK Financing II Limited | Financial services | 2020 |
| Becton Dickinson UK Holdings II Limited | Financial services | 2024 |
| Bedac Limited | Construction | 1998 |
| Bellace Consulting Ltd | Wholesale & retail | 2024 |
| Bells Engineering Products Limited | Wholesale & retail | 1997 |
| Bengal Spice (UK) Limited | Hospitality | 2002 |
| Berkshire 4X4 Show Limited | Arts & recreation | 2008 |
| Berkshire Buildings Limited | Wholesale & retail | 1994 |
| Berkshire Business Machines Limited | Transport & logistics | 1977 |
| Berkshire CAD Associates Limited | Professional & scientific | 1996 |