| A Flock Ascending Limited | Information & communication | 2018 |
| A Gold KG Limited | Arts & recreation | 2025 |
| A Good Place Therapy Ltd | Real estate | 2025 |
| A Hint of Yellow Limited | Wholesale & retail | 2011 |
| A J Robertson Limited | Wholesale & retail | 2010 |
| A Little CUP Tea Ltd | Wholesale & retail | 2021 |
| A M Kane Limited | Hospitality | 2002 |
| A Moustafa Ltd. | Health & social care | 2024 |
| A New Icon Limited | Information & communication | 2022 |
| A OK Productions Limited | Information & communication | 2023 |
| A P Dental Associates Limited | Health & social care | 2005 |
| A Resilient Mind Limited | Professional & scientific | 2016 |
| A Room in the Garden Ltd | Construction | 2017 |
| A S Murray Consulting Limited | Professional & scientific | 2020 |
| A to B Removals Brothers Ltd | Transport & logistics | 2026 |
| A W Avery Ltd | Administrative & support | 1978 |
| A&Aw Communications Ltd | Professional & scientific | 2020 |
| A&F Training and Consulting Ltd | Professional & scientific | 2026 |
| A&J Motorcycles Limited | Wholesale & retail | 2025 |
| A&M Design Projects Ltd | Professional & scientific | 2022 |
| A&S Drinks Limited | Wholesale & retail | 2024 |
| A&S Morrow Ltd | Information & communication | 2013 |
| A-Spec Carpentry Ltd | Construction | 2008 |
| A-Spec Homes Ltd | Administrative & support | 2012 |
| A-Team Care Ltd | Administrative & support | 2014 |
| A-Team Cleaning and Maintenance Ltd | Other services | 2010 |
| A. Simmons Carpentry Ltd. | Manufacturing | 2019 |
| A.B.C. Landscapes Limited | Administrative & support | 2004 |
| A.G.R. Scaffolding Ltd | Construction | 2011 |
| A.J. Haywood Limited | Construction | 2003 |
| A.J. Taylor Electrical Contractors Limited | Construction | 1997 |
| A.K. & Co. (Accountancy Services) Limited | Professional & scientific | 1992 |
| A.L.N Specialists Limited | Construction | 2015 |
| A.M. Construction (Southern) Limited | Construction | 2003 |
| A.M.M Group Ltd | Transport & logistics | 2025 |
| A.P.M. Scaffolding Ltd | Construction | 2019 |
| A.P.R. Entertainment Limited | Administrative & support | 2020 |
| A.S.M. Electric Cooker Repairs Ltd | Other services | 2004 |
| A1 Hove Limited | Hospitality | 2018 |
| A2B Express Logistics Ltd | Transport & logistics | 2012 |
| A2Y CIC | Wholesale & retail | 2023 |
| AA 2000 Limited | Professional & scientific | 1997 |
| AA Motorcycles Limited | Wholesale & retail | 2026 |
| AA Traffic Ltd | Transport & logistics | 2025 |
| Aa&Jj Food Ltd | Hospitality | 2019 |
| AAA Artists and Events Ltd | Arts & recreation | 2024 |
| AAA House Ltd | Real estate | 2021 |
| AAC Utility Services Ltd | Other services | 2025 |
| Aaka Runs Ltd | Arts & recreation | 2024 |
| Aaranma Limited | Health & social care | 2025 |
| Aarav & Khushi Ltd | Health & social care | 2020 |
| Aaron Nutrition Limited | Health & social care | 2023 |
| Aaron Yusuf Ltd | Public administration | 2020 |
| AB Agile Ltd | Professional & scientific | 2025 |
| AB Dental Group Limited | Health & social care | 2021 |
| AB Yacht Design & Naval Architecture Limited | Professional & scientific | 2023 |
| ABC Developments Carpentry & Construction Ltd | Construction | 2021 |
| ABC Oral Health Ltd | Health & social care | 2026 |
| Abdo Ltd | Construction | 2026 |
| ABI Scientific Holdings Limited | Financial services | 2025 |
| Abinger Road VG Limited | Real estate | 2025 |
| Abiru Ltd | Hospitality | 2010 |
| ABIX2000 Limited | Information & communication | 2008 |
| Able Consulting Limited | Wholesale & retail | 2006 |
| Ablesign Ltd | Information & communication | 2023 |
| ABM Orthodontics Limited | Health & social care | 2024 |
| ABQ Studio Limited | Professional & scientific | 2002 |
| ABQ Workshop Limited | Construction | 2014 |
| Abragold Limited | Households | 2001 |
| Abraham Kritzman Studio Ltd | Arts & recreation | 2022 |
| Abraway Limited | Households | 2001 |
| Absolute Alchemy Limited | Education | 2015 |
| Absolute Social Care Training Solutions Ltd | Education | 2022 |
| Absolute Speed Ltd | Manufacturing | 2020 |
| Absolute Town Planning Ltd | Professional & scientific | 2017 |
| Abstract Base Limited | Information & communication | 2005 |
| Abstract Psychotherapy Ltd | Health & social care | 2025 |
| Abuellaias Ltd | Hospitality | 2026 |
| AC Imaging Diagnostics Ltd | Health & social care | 2024 |
| AC Wealth Management Limited | Financial services | 2022 |
| Academy of Natural Medicine Ltd | Health & social care | 2018 |
| Accadian Ltd | Professional & scientific | 2012 |
| Accounting Solution (Sussex) Ltd | Professional & scientific | 2009 |
| Accountsoffice (Hove) Limited | Professional & scientific | 2013 |
| Accura Energy Ltd | Professional & scientific | 2011 |
| Ace Travel (Sussex) Limited | Transport & logistics | 2005 |
| ACI Home Improvement Limited | Manufacturing | 2024 |
| Ackerworx Ltd | Information & communication | 2023 |
| Acorn Inc Ltd | Wholesale & retail | 2015 |
| Acoustic Attenuations Ltd | Manufacturing | 1992 |
| Acpath Limited | Health & social care | 1996 |
| Acph Limited | Health & social care | 2010 |
| Acquaviva Ltd | Health & social care | 2013 |
| Acronym Institute for Disarmament Diplomacy | Information & communication | 1996 |
| ACS Building Services Ltd | Construction | 2008 |
| ACS Business Performance Ltd | Administrative & support | 2007 |
| ACS Executive Limited | Professional & scientific | 2026 |
| ACT III Ltd | Information & communication | 2023 |
| ACT OFF Holdings Limited | Financial services | 2025 |
| ACT OFF Limited | Wholesale & retail | 2025 |