| 08773894 Limited | Professional & scientific | 2013 |
| 1 LP Limited | Administrative & support | 2012 |
| 1-2 Alexandra Terrace RTM Company Limited | Households | 2014 |
| 10 Lavant Road Management Company Ltd | Households | 2021 |
| 11 Mill Road Worthing Limited | Households | 2008 |
| 17 Tarrant Street RTM Company Limited | Households | 2012 |
| 180216 Ltd | Administrative & support | 2016 |
| 2TC Limited | Manufacturing | 2002 |
| 2XLP Ltd | Professional & scientific | 2018 |
| 3C Training Ltd | Education | 2024 |
| 55 Aylesford Street Limited | Households | 2007 |
| 765 Ltd | Construction | 2026 |
| 82 Consultancy Limited | Professional & scientific | 2022 |
| A&J Scaffolding & Roofing Ltd | Construction | 2026 |
| A&J Scaffolding Ltd | Construction | 2021 |
| A. C. Gardens ( Sussex ) Ltd. | Administrative & support | 2018 |
| A.B. Autos (Arundel) Limited | Wholesale & retail | 2013 |
| A.Booker & SON Limited | Real estate | 1955 |
| A.L.R. Consulting Limited | Professional & scientific | 2004 |
| Abec-Apollo Limited | Professional & scientific | 2004 |
| ACCESS2HEALTHCARE Ltd | Financial services | 2010 |
| Ace Removals Sussex Ltd | Transport & logistics | 2025 |
| Adam Heraty Ltd | Transport & logistics | 2018 |
| Admiralty Residents Association Limited | Households | 2000 |
| Adrian Bush Limited | Professional & scientific | 2013 |
| Advanced Ventilation Systems Ltd | Manufacturing | 2007 |
| Aegisgovernance Ltd | Information & communication | 2025 |
| Aircooled Tuning Limited | Manufacturing | 2012 |
| AL Ikin Ltd | Health & social care | 2018 |
| Alan Sargent Consultancy Limited | Professional & scientific | 2016 |
| Albiston Business Consultancy Limited | Professional & scientific | 2006 |
| Albiston Property Investments Ltd | Real estate | 2023 |
| Aldwick Property Management Limited | Households | 2015 |
| Aletheia Serene UK Ltd | Professional & scientific | 2022 |
| Allium Management Ltd | Real estate | 2020 |
| Allouison Limited | Professional & scientific | 2012 |
| Almeys Heating and Plumbing Limited | Construction | 2015 |
| Alt-D Limited | Information & communication | 2019 |
| Amberley Museum & Heritage Centre | Arts & recreation | 1978 |
| Amberley Museum (Retail) Ltd | Wholesale & retail | 1986 |
| Amhc Europe Limited | Professional & scientific | 2023 |
| AMP Insights Ltd | Professional & scientific | 2025 |
| Ampr Trading Ltd | Wholesale & retail | 2020 |
| Andrew Dempsey Limited | Professional & scientific | 2007 |
| Angel Rose Digital Marketing Ltd | Wholesale & retail | 2025 |
| Angel Yard (Midhurst) Limited | Households | 2009 |
| Angelfish (Southampton) Limited | Hospitality | 1999 |
| Angmering Park Farms LLP | | 2009 |
| ANP Care Limited | Health & social care | 2015 |
| AOG Europe Limited | Transport & logistics | 2021 |
| AP Personal Nails Care Ltd | Other services | 2026 |
| Apex Carpentry and Construction Limited | Construction | 2021 |
| Apple Tree Administrative Ltd | Administrative & support | 2025 |
| Appletree Cleaning Limited | Administrative & support | 2022 |
| Appletree Window Cleaning Limited | Administrative & support | 2010 |
| Applianceguarduk Limited | Information & communication | 2019 |
| Aqualife Swim School Ltd | Arts & recreation | 2014 |
| ARCS24 Ltd | Transport & logistics | 2024 |
| Arrival Components LLP | | 2006 |
| Arrival Electronics Limited | Manufacturing | 2009 |
| Arun Landscapes Limited | Administrative & support | 2005 |
| Arun Rural Developments Limited | Agriculture & fishing | 2007 |
| Arun Tech Support Ltd | Information & communication | 2019 |
| Arun to Adur Cluster Limited | Professional & scientific | 2021 |
| Arun Tree Company Ltd | Agriculture & fishing | 2003 |
| Arundel and Downland Community Leisure Trust | Arts & recreation | 2001 |
| Arundel Bathroom & Kitchen Ltd | Construction | 2026 |
| Arundel Brewery Limited | Manufacturing | 1992 |
| Arundel Builders Ltd | Construction | 1993 |
| Arundel Carpentry Ltd | Manufacturing | 2022 |
| Arundel Castle Cricket Foundation | Arts & recreation | 2012 |
| Arundel Castle Enterprises Limited | Wholesale & retail | 1980 |
| Arundel Castle Trustees Limited | Arts & recreation | 1976 |
| Arundel Clinic Limited | Health & social care | 2015 |
| Arundel Community Partnership Limited | Health & social care | 2009 |
| Arundel Community Trust Services Limited | Arts & recreation | 2004 |
| Arundel Dental Care Ltd | Health & social care | 2015 |
| Arundel Events Ltd | Arts & recreation | 2024 |
| Arundel Gate Finance Limited | Financial services | 2023 |
| Arundel Great Court LLP | | 2022 |
| Arundel Jewellers Limited | Wholesale & retail | 2013 |
| Arundel Mount Pleasant Land Ltd | Households | 2010 |
| Arundel Museum (Trading) Limited | Arts & recreation | 2011 |
| Arundel Museum Society | Other services | 2011 |
| Arundel Players | Arts & recreation | 2020 |
| Arundel Services Limited | Real estate | 1981 |
| Arundel Spice House Ltd | Hospitality | 2017 |
| Arundel Stoneworks Ltd | Construction | 2019 |
| Arundel Taphouse Limited | Hospitality | 2025 |
| Arxpoint Limited | Wholesale & retail | 2025 |
| ASF Chichester Ltd | Arts & recreation | 2025 |
| ASH Ventures Limited | Households | 2008 |
| Asian Bazaar UK Ltd | Wholesale & retail | 2025 |
| Astons Health & Wellbeing Limited | Health & social care | 2017 |
| ATB Sussex Ltd | Wholesale & retail | 2025 |
| Atelier Fire Limited | Wholesale & retail | 2023 |
| Atherley Associates Ltd. | Professional & scientific | 2012 |
| ATS Connection Ltd | Information & communication | 2023 |
| Aurora Goring Limited | Households | 2011 |
| Aurum Builds Ltd | Construction | 2026 |