| AQT Holdings Limited | Professional & scientific | 2018 |
| Arboraeration Ltd | Administrative & support | 2018 |
| Arborfield Consultants Limited | Administrative & support | 2016 |
| Arc-It Business Solutions Ltd | Professional & scientific | 2015 |
| Archarry Ltd | Administrative & support | 2021 |
| Archdale Works Limited | Professional & scientific | 2023 |
| Archie Designs Limited | Extraterritorial | 2014 |
| Archmeadow Limited | Information & communication | 2008 |
| Argentis Properties Limited | Real estate | 2017 |
| Argie Built Ltd | Construction | 2026 |
| Arksey Holdings Limited | Financial services | 2013 |
| Arla Property Limited | Real estate | 2019 |
| ARM Locksmiths Limited | Other services | 2019 |
| Arnott Electrical Limited | Construction | 2007 |
| Arnside Buildings Limited | Administrative & support | 2014 |
| Arolla Limited | Construction | 2014 |
| Arron James Property Solutions Ltd | Real estate | 2024 |
| Arrowtown Drinks Limited | Manufacturing | 2019 |
| Artchocolat Ltd | Manufacturing | 2019 |
| Artemis Design & Build Limited | Construction | 2014 |
| Arthur E.Mason Limited | Manufacturing | 1963 |
| Artyard Cafe Limited | Hospitality | 2015 |
| Asap Refrigerated Ltd | Transport & logistics | 2017 |
| ASD Property Solutions LLP | | 2011 |
| ASD Unique Services LLP | | 2011 |
| Ashburnham Associates Limited | Professional & scientific | 2004 |
| Ashdown Consultancy Limited | Professional & scientific | 2003 |
| Ashgrove Garage Ltd | Wholesale & retail | 2019 |
| Ashlar Consultancy Ltd | Information & communication | 2026 |
| Ashley Hodge Electrical Services Limited | Professional & scientific | 2010 |
| ASK 4 Homes Limited | Construction | 2018 |
| ASK 4 Renovations Limited | Construction | 2003 |
| ASL Locksmiths and Security Solutions Ltd | Administrative & support | 2022 |
| ASP Access Floors Limited | Construction | 2009 |
| ASP Access Floors Nordic Limited | Construction | 2013 |
| Aspen a. C. Ltd | Energy | 1987 |
| Aspen Pumps Limited | Manufacturing | 2012 |
| Aspen Renewables Ltd | Professional & scientific | 2001 |
| Aspen Service Ltd | Other services | 1995 |
| Associated Brands UK Limited | Information & communication | 2006 |
| Aster Emerald Ltd | Real estate | 2022 |
| Atis Legal Limited | Professional & scientific | 2026 |
| Atlantic Corporate Partners Limited | Administrative & support | 2005 |
| Atlantic Tax Advisory Services Ltd | Professional & scientific | 2016 |
| Atlas Southern Roofing Ltd | Construction | 2021 |
| ATR & Partners Limited | Information & communication | 2019 |
| Atra Europe Ltd | Other services | 2023 |
| Audiofilm.Com Limited | Information & communication | 2015 |
| Aultra Brickwork Ltd | Construction | 2023 |
| Auraseed Ltd | Professional & scientific | 2023 |
| Aurora Anaesthesia Limited | Health & social care | 2025 |
| Austen Time Productions Ltd | Information & communication | 2024 |
| Austin Pegg Racing Ltd | Wholesale & retail | 2025 |
| Austin Wright Ltd | Professional & scientific | 2019 |
| Auto Gearbox Holdings Ltd | Financial services | 2023 |
| Autoclave Service & Repairs Limited | Professional & scientific | 1999 |
| Automutatio Ltd | Information & communication | 2020 |
| Autopoint Specialist Engineering Limited | Wholesale & retail | 2008 |
| AVE Technologies Ltd | Manufacturing | 2018 |
| Aves Type Limited | Manufacturing | 2013 |
| AVG Partners Limited | Administrative & support | 2025 |
| Avion Health LLP | | 2026 |
| Awesome Property Limited | Real estate | 2024 |
| Aysar Car Care Ltd | Wholesale & retail | 2019 |
| Aysgarth Estates Limited | Real estate | 2025 |
| B & a Property Developments Ltd | Construction | 2018 |
| B Davies Utilities Ltd | Construction | 2024 |
| B K Ceramics Limited | Construction | 2003 |
| B M Groundworks Limited | Construction | 2022 |
| B M Holdings Limited | Wholesale & retail | 1997 |
| B Williams Medical Services Limited | Health & social care | 2018 |
| B.S.J. Developments Limited | Real estate | 2014 |
| B3 Business Ltd | Professional & scientific | 2022 |
| BA Machine Ltd | Manufacturing | 2022 |
| Babble Central Limited | Hospitality | 2024 |
| Baby Bank & Beyond (South Wealden) CIC | Administrative & support | 2023 |
| Babylon Homes Ltd | Real estate | 2020 |
| Bailey & Bailey Properties Limited | Real estate | 2020 |
| Bailey Holdings (Sussex) Limited | Financial services | 2023 |
| Balcombes DIY Ltd | Wholesale & retail | 2019 |
| Baldock & KIN Ltd | Real estate | 2025 |
| Ballers & Family Consulting Limited | Other services | 2023 |
| Bambino Boutique Ltd | Wholesale & retail | 2016 |
| Bamford Tree Management Ltd | Administrative & support | 1996 |
| Bancroft Holdings (Sussex) Limited | Financial services | 2001 |
| Bank House Properties Ltd | Construction | 2022 |
| Bankzy Ltd | Professional & scientific | 2022 |
| Barbers Franchising Limited | Other services | 2024 |
| Barkweb Limited | Information & communication | 2003 |
| Barn Farm Estates Management Limited | Arts & recreation | 2015 |
| Barnfield (UK) Limited | Wholesale & retail | 2008 |
| Barong Conservatories (South-East) Limited | Construction | 2008 |
| Barracloughs Holdings Limited | Financial services | 2016 |
| Barrington's Rentals Ltd | Other services | 2024 |
| Baseline-Rts Ltd | Administrative & support | 2018 |
| Bassetts of Horsmonden Ltd | Real estate | 2025 |
| Bates & Co. Limited | Real estate | 2004 |
| Battle Homes (Sussex) Ltd | Real estate | 1997 |
| BCP Plumbing and Heating Contractor Limited | Construction | 2015 |
| BCW Contracts Limited | Construction | 2022 |