| AM1029 Properties Ltd | Real estate | 2019 |
| Amahlathi Ltd | Agriculture & fishing | 2024 |
| Amakhala (Winchester) Limited | Professional & scientific | 2021 |
| Amapola Pro Ltd | Real estate | 2022 |
| Amar Infinity Capital Limited | Real estate | 2023 |
| Amarchitect Ltd | Professional & scientific | 2021 |
| Amari RAI Limited | Real estate | 2025 |
| Amati Limited | Professional & scientific | 1999 |
| Ambassador Marine Limited | Manufacturing | 1986 |
| Ambell Holdings Ltd | Professional & scientific | 2022 |
| Amber Residential Care Homes Ltd | Health & social care | 2000 |
| Amberdesigns Limited | Extraterritorial | 2000 |
| Ambmead Limited | Households | 1973 |
| Ambrett Holdings Limited | Mining & quarrying | 2024 |
| Amcotshire Ltd. | Professional & scientific | 2022 |
| Amelie Poppy Anne Ltd | Real estate | 2013 |
| Amhurst (Winchester) Limited | Administrative & support | 1997 |
| Amlyn Chauffeurs Ltd | Transport & logistics | 2017 |
| Amplitude Music Limited | Professional & scientific | 2015 |
| AMS Property Rental Worldwide Limited | Real estate | 2022 |
| Analec Trustees Limited | Extraterritorial | 2012 |
| Anaraa Consulting Ltd | Professional & scientific | 2022 |
| Anaraa Law Ltd | Professional & scientific | 2022 |
| Anaraa Strategy Ltd | Professional & scientific | 2023 |
| Ancells Court Management Company Limited | Real estate | 1989 |
| Anchorage Consulting Services Ltd | Professional & scientific | 2019 |
| AND Apple PIE Consulting Limited | Professional & scientific | 2019 |
| Andahl Ltd | Administrative & support | 2010 |
| Anderson Turner Limited | Professional & scientific | 2017 |
| Andile Holding Limited | Financial services | 2021 |
| Andmarc Cars Ltd | Wholesale & retail | 2017 |
| Andover Bathroom Collection Ltd | Wholesale & retail | 2019 |
| Andover Car Repairs Ltd | Wholesale & retail | 2019 |
| Andover Car Sales Limited | Wholesale & retail | 2022 |
| Andover Garden Buildings Ltd | Construction | 2002 |
| Andover Town Football Club Limited | Arts & recreation | 2013 |
| Andr Productions Ltd. | Administrative & support | 2019 |
| Andrew Biebuyck Ltd | Wholesale & retail | 2023 |
| Andrew Burgess Planning Ltd | Professional & scientific | 2022 |
| Andrew Gordon Consulting Limited | Professional & scientific | 2019 |
| Andrew Hodgson Product Design Limited | Professional & scientific | 2020 |
| Andrew Jenvey Limited | Professional & scientific | 2016 |
| Andrew Jenvey Probate Limited | Professional & scientific | 2019 |
| Andrew Smith & SON (Winchester Auction Rooms) Limited | Professional & scientific | 2010 |
| Andrew Talbot Ltd | Wholesale & retail | 2025 |
| Andrews of Otterbourne Limited | Wholesale & retail | 2024 |
| Andro Hair Ltd | Wholesale & retail | 2026 |
| Andtech Limited | Professional & scientific | 2023 |
| Anexus Pharma Ltd | Professional & scientific | 2018 |
| ANG Psychology Limited | Education | 2025 |
| Angel Sports Ltd | Wholesale & retail | 2023 |
| Anglonormandy Ltd | Professional & scientific | 2013 |
| Angryginge Enterprises Ltd | Information & communication | 2022 |
| Aniane Limited | Administrative & support | 2013 |
| Animal Physiotherapy Centre Ltd | Professional & scientific | 2020 |
| Animate Puppet Co CIC | Education | 2025 |
| Anita Green Hair Studio Ltd | Other services | 2026 |
| Anlind Limited | Information & communication | 2010 |
| Anlusi Limited | Professional & scientific | 2015 |
| Anna Becvar Consultancy Limited | Professional & scientific | 2010 |
| Annie Holmes Tutoring Ltd | Education | 2023 |
| ANP Luxury Ltd | Manufacturing | 2026 |
| Ansacode Limited | Real estate | 1980 |
| Anson Game & Forestry Ltd | Agriculture & fishing | 2026 |
| Anstruther GC Limited | Professional & scientific | 2010 |
| Ansty Electrical Ltd | Administrative & support | 2016 |
| Antara Surgical Services Ltd | Health & social care | 2017 |
| Antares Global Limited | Other services | 2020 |
| Antdav Investments London Limited | Financial services | 2022 |
| Anthony Finance Limited | Financial services | 2013 |
| Anthony Smith HE Consulting Limited | Professional & scientific | 2024 |
| Antique Fine Jewellery Limited | Wholesale & retail | 2018 |
| Antoine Price Ltd | Wholesale & retail | 2018 |
| Antony Fanshawe Limited | Professional & scientific | 2022 |
| Anvi Bistro Ltd | Hospitality | 2026 |
| AO Consulting Ltd | Professional & scientific | 2024 |
| AP Electrical Design Limited | Construction | 2014 |
| AP Management Partners Ltd | Professional & scientific | 2026 |
| Apella Solutions Ltd | Administrative & support | 2006 |
| APF Property Services Ltd | Real estate | 2019 |
| Aphes Solutions Ltd | Professional & scientific | 2026 |
| Apollo Passive Fire Ltd | Construction | 2026 |
| Apollo Plastering Limited | Construction | 2020 |
| Apollo Signs & Graphics Limited | Wholesale & retail | 2020 |
| Apphias Way Ltd | Public administration | 2019 |
| Apple Crumble Ltd | Professional & scientific | 2024 |
| Appleton 101 Limited | Real estate | 2021 |
| Applewood LLP | | 2008 |
| Appysoft Ltd | Information & communication | 2014 |
| Aputiak Limited | Real estate | 2021 |
| Aqua Africa Ltd. | Construction | 2013 |
| Aqua Carbon Ltd | Professional & scientific | 2018 |
| Aqua Sulis Financial Management Limited | Financial services | 2017 |
| AR Design Studio Ltd | Professional & scientific | 2011 |
| ARA London Apparel Ltd | Wholesale & retail | 2026 |
| Arbrook Consulting Ltd | Professional & scientific | 2025 |
| Arcadia Search Ltd | Administrative & support | 2024 |
| Arcana (Winchester) Limited | Other services | 2005 |
| Arcana Limited | Other services | 1992 |
| Arcana Romsey Limited | Other services | 2025 |