| A&M Roofing London Ltd | Construction | 2025 |
| A. Pro Ltd | Construction | 2026 |
| A.B.C. Structures Ltd | Administrative & support | 2008 |
| A.J Homes and Developments Ltd | Construction | 2024 |
| A.P. Plumbing Services Limited | Construction | 2018 |
| A.W Drylining Specialist Ltd | Construction | 2021 |
| A23 Limited | Information & communication | 2017 |
| A259 Recruitment Ltd | Administrative & support | 2023 |
| A4 Labels.Com Limited | Wholesale & retail | 2011 |
| ABC Swim School London Ltd | Arts & recreation | 2014 |
| ABG Property Ltd | Households | 2018 |
| ABP London Limited | Wholesale & retail | 2022 |
| Abracadabra Broadcasting & Communications Limited | Professional & scientific | 2005 |
| AC Global Services Ltd | Energy | 2019 |
| Acacia Court Limited | Households | 1997 |
| Accnet Limited | Professional & scientific | 2002 |
| Accordant (RDA) UK Limited | Financial services | 2026 |
| Acorn Foodservices Limited | Wholesale & retail | 2017 |
| Acoustic Associates Trustees Limited | Professional & scientific | 2021 |
| Activities 4 Kids Ltd | Health & social care | 2018 |
| AD Magic Ltd | Professional & scientific | 2021 |
| Adam Scourfield Limited | Information & communication | 2014 |
| Adult Care Assessment Limited | Professional & scientific | 2014 |
| Adur Aviation Ltd. | Transport & logistics | 2024 |
| Adur Cafes Ltd | Hospitality | 2019 |
| Adur Community Cafe Community Interest Company | Hospitality | 2020 |
| Adur Investments Ltd | Real estate | 2016 |
| Adur Outdoor Activities Centre Ltd | Other services | 2024 |
| Adur Oyster Company Ltd | Agriculture & fishing | 2022 |
| Adur Property Management Ltd | Real estate | 2011 |
| Adurproperty Ltd | Extraterritorial | 2013 |
| Advanced Solutions International (Europe) Limited | Information & communication | 2004 |
| Advantage Kare Ltd | Health & social care | 2025 |
| AE Consulting Services Ltd | Professional & scientific | 2018 |
| Aerial Rigging Techniques Limited | Construction | 2009 |
| Aerovolt Sportair Ltd | Administrative & support | 2024 |
| Aerovolt UK Ltd | Administrative & support | 2022 |
| Aesthetics by Robyn Ltd | Health & social care | 2025 |
| Affordable Flooring Shoreham Limited | Construction | 2019 |
| Agkcarpentry Limited | Construction | 2025 |
| AHE Tutoring Ltd | Education | 2018 |
| Airbus Flight Training Ltd | Transport & logistics | 2010 |
| AJ Wootton Design Ltd | Professional & scientific | 2014 |
| AJ Wootton Properties Ltd | Real estate | 2022 |
| Ajna Limited | Hospitality | 2025 |
| AJW Accountancy Services Limited | Professional & scientific | 2015 |
| AJW Trading Limited | Wholesale & retail | 2016 |
| AL Fady Import and Export Ltd | Wholesale & retail | 2020 |
| Albatross RAE Limited | Professional & scientific | 2010 |
| Albion Ferry Ltd | Wholesale & retail | 2020 |
| Albright Commercial Cleaning (Lewes) Limited | Other services | 2018 |
| Alchemy Squared Limited | Professional & scientific | 2016 |
| Aldrington Press Limited | Manufacturing | 1984 |
| Alex Nicoll Business Management Limited | Professional & scientific | 2010 |
| Alex Tozzi Limited | Extraterritorial | 2017 |
| Alfamatas Ltd | Transport & logistics | 2015 |
| Alginon Limited | Professional & scientific | 2023 |
| ALI Walker Landscapes Ltd | Administrative & support | 2021 |
| Aliport Commercial Limited | Extraterritorial | 2014 |
| Aliport Designs Limited | Professional & scientific | 2007 |
| Aliport Limited | Manufacturing | 1984 |
| ALL Over Adur Limited | Administrative & support | 2013 |
| ALL Ventilation & Extraction Limited | Construction | 2012 |
| Allpark Leisure Limited | Arts & recreation | 2014 |
| Alonso Marshall Associates Limited | Professional & scientific | 2005 |
| ALP Dental Services Ltd | Health & social care | 2018 |
| Alpamayo Group Ltd | Administrative & support | 2024 |
| Altum Performance Ltd | Education | 2021 |
| Amanda Loy-Ellis Consulting Limited | Professional & scientific | 2015 |
| AMH Electrical Contractors Ltd | Construction | 2023 |
| Ampc Group Ltd | Information & communication | 2024 |
| Andy Sturgeon Garden Design Limited | Professional & scientific | 2005 |
| Angel Academe (Nuggets) Nominee Limited | Administrative & support | 2019 |
| Angel Academe Ltd | Information & communication | 2007 |
| Animalive Ltd. | Information & communication | 2011 |
| Anovhh Ltd | Hospitality | 2025 |
| Anovr Ltd | Hospitality | 2026 |
| Aperture Corporate Events Limited | Arts & recreation | 2016 |
| Appa Technical Holdings Limited | Financial services | 2014 |
| Appleton Works Ltd | Information & communication | 2019 |
| Application Fire and Security Solutions Limited | Administrative & support | 2019 |
| APT Business Accountancy Ltd | Professional & scientific | 2021 |
| Aptus Asset Management Ltd | Construction | 2015 |
| Aqua Fish (UK) Limited | Wholesale & retail | 2013 |
| Aquahounds Limited | Other services | 2024 |
| Ariyan Capital Limited | Information & communication | 2018 |
| Arrobas & CIA Ltd | Hospitality | 2004 |
| ARS Software Solutions PVT Ltd | Information & communication | 2022 |
| Art Care Solutions Limited | Administrative & support | 2021 |
| Artful Enterprises Limited | Arts & recreation | 2003 |
| Articulo Ltd | Wholesale & retail | 2020 |
| Arundel House (Hove) Management Company Limited | Households | 1996 |
| Arundel House Freehold Limited | Households | 1997 |
| Arundels Construction (Sussex) Limited | Construction | 2026 |
| Arundels Construction Limited | Construction | 2024 |
| Arvapro Vehicle Repairs Ltd | Wholesale & retail | 2025 |
| ASH & Plumb Ltd | Arts & recreation | 2019 |
| Ash's Barber Ltd | Other services | 2025 |
| Ashley Denman Stocktaking Limited | Other services | 2003 |
| Astoria Marketing & PR Ltd | Extraterritorial | 2024 |