| Alltrust Eput NO 2 Trustees Limited | Professional & scientific | 2025 |
| Alltrust Holdings Limited | Financial services | 2005 |
| Alltrust Investment Trustees Limited | Professional & scientific | 2025 |
| Alltrust Limited | Professional & scientific | 2005 |
| Alltrust Oasis Limited | Professional & scientific | 2008 |
| Alltrust Services Limited | Financial services | 2005 |
| Alltrust Sipp Limited | Professional & scientific | 2005 |
| Alltrust Ssas Limited | Professional & scientific | 2011 |
| Allwyn's Kitchen Ltd | Hospitality | 2024 |
| Almeric Legal Limited | Professional & scientific | 2019 |
| Almority Consulting Limited | Professional & scientific | 2025 |
| Almroth Enterprises Limited | Professional & scientific | 2006 |
| Alpamayo Coaching Ltd | Professional & scientific | 2016 |
| Alpha Commodity Solutions Limited | Professional & scientific | 2017 |
| Alpha Decorating Limited | Construction | 2022 |
| Alpha House RTM Company Limited | Households | 2026 |
| Alpha MEP Consulting Ltd | Professional & scientific | 2023 |
| Alpha Roofing Solutions Limited | Construction | 2018 |
| Alpha Scorpii Ltd | Information & communication | 2021 |
| Alpine Property Investments Limited | Administrative & support | 2006 |
| Alresford Building and Plumbing Ltd | Construction | 2020 |
| Altotech Ltd | Administrative & support | 2012 |
| Altus Living Ltd | Wholesale & retail | 2020 |
| Altx Cars Ltd | Wholesale & retail | 2024 |
| Altx Properties Ltd | Real estate | 2025 |
| Alutayem Medical Consultancy Ltd | Health & social care | 2022 |
| Aluztra BIO Limited | Professional & scientific | 2014 |
| Alva Switch UK Ltd | Manufacturing | 2025 |
| Alvediston Stud Limited | Agriculture & fishing | 2005 |
| AM Accounting (Salisbury) Ltd | Professional & scientific | 2023 |
| Amara Bespoke Beauty Ltd | Other services | 2016 |
| Amaranta Restaurants Limited | Hospitality | 2017 |
| Ambassador Distribution Limited | Transport & logistics | 2012 |
| Amber Slack Design Ltd | Professional & scientific | 2021 |
| Ambient Support Limited | Health & social care | 2010 |
| Ambiheat Ltd | Construction | 2022 |
| Ambrose Plumbing & Heating Ltd | Construction | 2025 |
| AME Southern Ltd | Construction | 2014 |
| Amen Corner (Binfield) Management Company Limited | Households | 2017 |
| American Cruiser UK Limited | Administrative & support | 2023 |
| Amesbury Filling Station Ltd | Wholesale & retail | 2012 |
| Amesbury Group Limited | Hospitality | 2025 |
| Amesbury OFF Licence Ltd | Wholesale & retail | 2025 |
| Amesbury Pets Limited | Wholesale & retail | 2019 |
| Amesbury Printing Company Limited | Information & communication | 2000 |
| Amesbury Rugby Club Ltd | Arts & recreation | 2018 |
| Amesbury's Motor Garage Ltd | Other services | 2016 |
| Amigos Pizza & Burger Ltd | Hospitality | 2025 |
| Amigos Pizza Ltd | Hospitality | 2014 |
| Amit Shah Property Ltd | Real estate | 2016 |
| Amjacc Ltd | Professional & scientific | 2020 |
| AML Analytics Ltd | Information & communication | 2010 |
| Amla Group Ltd | Information & communication | 2021 |
| Amlets Place (Cranleigh) Management Company Limited | Households | 2017 |
| Ammys Store Salisbury Limited | Wholesale & retail | 2025 |
| Amport Risk Limited | Administrative & support | 2017 |
| AMS (Salisbury) Ltd | Health & social care | 2021 |
| AN Buckingham Consultancy Limited | Professional & scientific | 2016 |
| An.X Limited | Professional & scientific | 2005 |
| Analysis Intuition Limited | Information & communication | 1997 |
| Anchor Joint Sealing Limited | Construction | 1975 |
| Anchor Point Industries Ltd | Information & communication | 2026 |
| Anchor Wharf (Polesworth) Management Company Limited | Households | 2023 |
| Andell Developments Limited | Construction | 2018 |
| Andiamo Exploration Limited | Administrative & support | 2008 |
| Andmax Limited | Manufacturing | 2023 |
| Andover Engineering Ltd | Professional & scientific | 2015 |
| Andover Plastering Limited | Construction | 2010 |
| Andover Vehicle Solutions Limited | Wholesale & retail | 2019 |
| Andsam Group Ltd | Construction | 2025 |
| Andy Henderson Property Limited | Real estate | 2025 |
| Andy Munns Ltd | Professional & scientific | 2023 |
| Aneric Healthcare Ltd | Administrative & support | 2021 |
| Angel IT Limited | Information & communication | 2010 |
| Angel Paws Veterinary Care Limited | Professional & scientific | 2023 |
| Angie Dooling Ltd | Professional & scientific | 2021 |
| Anglo-Irish (Insurance & Bloodstock) Agency Limited | Extraterritorial | 1987 |
| ANH Phong Ltd | Other services | 2022 |
| Animal Friends Limited | Professional & scientific | 2002 |
| Animal Love Grooming & Well-Being Ltd | Professional & scientific | 2014 |
| Anita Joy Sanders Hairdressing Ltd | Other services | 2024 |
| Ankledock Limited | Real estate | 1987 |
| Anna Goodman Consulting Ltd | Professional & scientific | 2022 |
| Anned Ltd | Construction | 2020 |
| Annetts & Orchard Ltd | Financial services | 2018 |
| Another General Company Ltd | Professional & scientific | 2021 |
| Ansbro Ltd | Manufacturing | 2020 |
| Anstey Management Company Limited | Households | 2020 |
| Ansty Publishing Limited | Information & communication | 2013 |
| Anthony Automobiles ( Salisbury ) Limited | Wholesale & retail | 2013 |
| Anthony Berry Limited | Administrative & support | 2006 |
| Anthony's Workshop Limited | Wholesale & retail | 2022 |
| Antler Investments Ltd | Real estate | 2024 |
| Antrobus Road Management Limited | Real estate | 2008 |
| ANU Services Limited | Administrative & support | 2025 |
| Anvil Vision Limited | Information & communication | 2019 |
| Aoff Ltd | Real estate | 2020 |
| Apex Fencing Ltd | Administrative & support | 2012 |
| Apexx Plastering Ltd | Construction | 2023 |
| Apicem Consulting Ltd | Professional & scientific | 2023 |