| Andy Smyth Carpets Limited | Construction | 2015 |
| Anemaj Lker Ltd | Wholesale & retail | 2025 |
| Angel Bookkeeping Limited | Professional & scientific | 2021 |
| Angel Importing Ltd | Wholesale & retail | 2018 |
| Angel Property (U.K.) Limited | Real estate | 1997 |
| Angelica Care Ltd | Health & social care | 2016 |
| Angelika Oles Holdings Limited | Financial services | 2020 |
| Angelika Oles Ltd | Information & communication | 2019 |
| Angell Heights Ltd | Real estate | 2025 |
| Angels Cleaning Services (Worthing) Ltd | Administrative & support | 2015 |
| Angie Holden Ltd | Information & communication | 2025 |
| Anglia Leasing Ltd | Wholesale & retail | 2013 |
| Angling 4 Education Limited | Arts & recreation | 2019 |
| Anglo Pountney Limited | Wholesale & retail | 2021 |
| Angmering Court Tenants' Association Limited | Real estate | 1971 |
| Angmering Electrical Services Ltd | Construction | 2019 |
| Angmering Scaffold Ltd | Construction | 2026 |
| Angola Ltd | Wholesale & retail | 2026 |
| Animation Supplies Ltd | Manufacturing | 2010 |
| Animus Group Limited | Administrative & support | 2023 |
| Anjaneya Trading Ltd | Wholesale & retail | 2026 |
| Anjeza Catering Ltd | Hospitality | 2021 |
| Anjin Advisers Limited | Financial services | 2023 |
| ANK Motor Fuel Ltd | Wholesale & retail | 2021 |
| Anmi Holding Limited | Real estate | 2024 |
| Annabella Worthing Limited | Other services | 2021 |
| Annandale Developments Ltd | Construction | 2017 |
| Anopenmind Ltd | Professional & scientific | 2022 |
| Anopoli Developments Limited | Other services | 2019 |
| ANS Local Couriers Ltd | Transport & logistics | 2022 |
| Antardrishti Analytics Ltd | Information & communication | 2023 |
| Anton Buyers Ltd | Professional & scientific | 2026 |
| Antsam Construction Ltd | Construction | 2018 |
| Anytime Plumbing Services Limited | Construction | 2016 |
| AP Automotive Solutions Limited | Wholesale & retail | 2024 |
| AP Joint Ventures Limited | Hospitality | 2020 |
| Apac Installations Ltd | Construction | 2015 |
| Apathetic Records Limited | Information & communication | 2019 |
| APC Marine Ltd | Manufacturing | 2022 |
| Apex Property (South) Ltd | Real estate | 2018 |
| Apex Roofing Sussex Limited | Construction | 2016 |
| Aphex Financial Planning Ltd | Professional & scientific | 2020 |
| API (Armchair Property Investments) Limited | Real estate | 2015 |
| API Technical Services Limited | Professional & scientific | 2005 |
| APM Walker Energy Services Limited | Professional & scientific | 2013 |
| Apogee Consulting Limited | Administrative & support | 2025 |
| Apollo Engineering & Services Ltd | Professional & scientific | 2021 |
| Apollo Mortgages Limited | Financial services | 2021 |
| Appealing Solutions Limited | Professional & scientific | 2023 |
| Appent Ltd | Wholesale & retail | 2020 |
| Appknowledged Ltd | Information & communication | 2021 |
| Applaud Solutions UK Ltd | Information & communication | 2008 |
| Apple RN Ltd | Health & social care | 2022 |
| Applecoe Studio Ltd | Information & communication | 2023 |
| Applepips Day Nursery Limited | Education | 2014 |
| Appletree Bay Consultancy Limited | Professional & scientific | 2023 |
| Applied Aesthetics Academy Ltd | Education | 2025 |
| Applied Kilovolts Limited | Manufacturing | 1987 |
| Appropriately Ltd | Wholesale & retail | 2026 |
| APS Devon and Cornwall Sewage Limited | Other services | 2024 |
| APS Workforce Solution Limited | Professional & scientific | 2021 |
| Aptivate | Information & communication | 2003 |
| Aptus Flow Ltd | Extraterritorial | 2022 |
| APV1 Leasehold Ltd | Real estate | 2025 |
| APV1 Shared Living Ltd | Real estate | 2025 |
| APV2 Shared Living Ltd | Real estate | 2025 |
| APV3 Coastal Living Ltd | Real estate | 2025 |
| APV4 Apartments Ltd | Real estate | 2025 |
| APV4 Properties Ltd | Real estate | 2025 |
| APV5 Shared Living Ltd | Real estate | 2025 |
| APV6 Apartments Ltd | Real estate | 2025 |
| APV7 Shared Living Ltd | Real estate | 2025 |
| AQ Consulting Limited | Professional & scientific | 2025 |
| Aquaducks Plumbing and Heating Limited | Construction | 2007 |
| Aquarius Engineering (Sussex) Ltd | Professional & scientific | 2021 |
| Aquatic 2012 CIC | Education | 2024 |
| Aquaview Consulting Ltd | Professional & scientific | 2022 |
| Aquila UW Ltd | Financial services | 2026 |
| Aragona Martial Arts Limited | Education | 2024 |
| Arann Retail Ltd | Wholesale & retail | 2025 |
| Aras Gyros Limited | Hospitality | 2024 |
| Arcade Business Management Limited | Professional & scientific | 2024 |
| Arcade Creative Limited | Administrative & support | 2024 |
| Arcade Group Ltd | Financial services | 2025 |
| Arcade Media Ltd | Other services | 2021 |
| Arcbridge International Ltd | Financial services | 2026 |
| Arcform.Tech Ltd | Information & communication | 2026 |
| Archer & Braun Ltd. | Professional & scientific | 2017 |
| Archers Healthcare Limited | Health & social care | 2016 |
| Archetara Ltd | Health & social care | 2023 |
| Archidrum Ltd | Professional & scientific | 2017 |
| Architectural Design Computer Services Limited | Professional & scientific | 1997 |
| Architectus Limited | Administrative & support | 1993 |
| Archive Works Limited | Information & communication | 2018 |
| Archon Holdings Limited | Financial services | 2026 |
| Arcist Ltd | Construction | 2017 |
| Arcurity Ltd | Information & communication | 2024 |
| Arcus Investment Holdings Limited | Financial services | 2020 |
| Arcus Investment Limited | Financial services | 1998 |
| Ardees BDC Ltd | Professional & scientific | 2025 |