| 107 ST James Road Residents Company Limited | Hospitality | 2003 |
| 10BUILD Ltd | Construction | 2019 |
| 125 Bravington Road Property Management Limited | Households | 2016 |
| 13 Junction Road Right to Manage Company Limited | Real estate | 2008 |
| 143 West END Lane Limited | Households | 2010 |
| 22 Point SIX (Maritime) Limited | Wholesale & retail | 2013 |
| 3 Step Designs Limited | Construction | 2015 |
| 300 Risk Limited | Professional & scientific | 2026 |
| 31 Compton Avenue (Brighton) Limited | Households | 2005 |
| 31 East Drive RTM Company Limited | Households | 2024 |
| 3CIP Solutions Limited | Other services | 2017 |
| 44 Manse Road Freehold Management Company Ltd | Real estate | 2010 |
| 46 ST James Road RTM Company Limited | Households | 2021 |
| 47 Pier Road Development Ltd | Construction | 2025 |
| 4D Visage Ltd | Education | 2015 |
| 4GI Limited | Financial services | 2014 |
| 4THEUK Limited | Information & communication | 2005 |
| 5 SJR Limited | Professional & scientific | 2020 |
| 5 T Consulting Ltd | Health & social care | 2011 |
| 57 Mill Road (Burgess Hill) Limited | Households | 2007 |
| 59 Hazelgrove Road Freehold Limited | Real estate | 2017 |
| 59 Mill Road RTM Company Limited | Households | 2020 |
| 5DCARPENTRY Ltd | Construction | 2019 |
| 6 Florence Road (Brighton) Ltd | Households | 2005 |
| 74 Group Limited | Administrative & support | 2017 |
| 76 Victoria Road Burgess Hill Management Company Limited | Households | 2015 |
| 89 Westbourne Street Management Company Limited | Households | 2007 |
| 92 High Street Limited | Other services | 2014 |
| A & a Technical Services Ltd | Professional & scientific | 2025 |
| A E Controls Limited | Information & communication | 2007 |
| A G P Sussex Limited | Administrative & support | 2009 |
| A Holden Plumbing and Heating Ltd | Construction | 2014 |
| A M Glazing & Maintenance Ltd | Construction | 2024 |
| A P Guthrie Ltd | Construction | 2016 |
| A P Sherlock Associates Limited | Professional & scientific | 2020 |
| A R Feaver Ltd | Agriculture & fishing | 2003 |
| A Rated Heating & Plumbing Ltd | Construction | 2017 |
| A S Building & Plumbing Limited | Construction | 2013 |
| A S Interiors Design Limited | Construction | 2010 |
| A&D Coffee Ltd | Hospitality | 2020 |
| A.B.M. Securities Limited | Real estate | 1972 |
| A.I.E. Services Limited | Manufacturing | 2005 |
| A.N Coropration Limited | Other services | 2014 |
| AA Dental Health Ltd | Health & social care | 2023 |
| AA Marmalade Properties Limited | Real estate | 2022 |
| AA Marmalade Rentals Ltd | Real estate | 2026 |
| Aaron Keating Electrical Services Ltd | Other services | 2010 |
| AB Brickwork & Stones Ltd | Construction | 2025 |
| Abbotsford Place Management Company Limited | Households | 2026 |
| Abru Estates Limited | Real estate | 2010 |
| Abundant Times Ltd | Professional & scientific | 2024 |
| Acar Chef Ltd | Hospitality | 2021 |
| Accelerated Systems Ltd | Information & communication | 2010 |
| Accolade Financial Planning Ltd | Financial services | 2025 |
| Accomplish Event Coaching Ltd | Other services | 2023 |
| Accountancy & Business Services (ABS) Ltd | Professional & scientific | 2014 |
| Ace Alarms & Security Systems Ltd | Administrative & support | 2026 |
| Ace Ready Academy Ltd | Education | 2025 |
| Aclegends Ltd | Education | 2026 |
| Acora Holdings Limited | Professional & scientific | 2006 |
| Acora Limited | Information & communication | 1989 |
| Acorn Lodge Sovereign Care Limited | Health & social care | 2017 |
| ACT TOO Stage School Ltd | Arts & recreation | 2006 |
| Action Creative Group Limited | Manufacturing | 2012 |
| Action Office Interiors Ltd | Manufacturing | 2012 |
| Action Workspace Limited | Construction | 2019 |
| Active Recruitment Consultants Limited | Administrative & support | 2008 |
| Ad-Value Consulting Limited | Professional & scientific | 2013 |
| Adam Baker Carpets Ltd | Construction | 2015 |
| Adam Pierre Building & Carpentry Contractor Ltd | Construction | 2009 |
| Addcare International Ltd | Administrative & support | 2017 |
| Addicted 2 PPC Limited | Professional & scientific | 2021 |
| Adforum Ltd | Professional & scientific | 2020 |
| Advance Computers Limited | Extraterritorial | 2005 |
| Adzain Ltd | Real estate | 2021 |
| Aegis Kerz Ltd | Real estate | 2023 |
| Aerialbeam Limited | Professional & scientific | 2011 |
| Aero Safety Advisory Ltd | Professional & scientific | 2012 |
| Affordable Sussex Housing Ltd | Real estate | 2026 |
| After Build Limited | Construction | 2003 |
| Aftercare Double Glazing Repairs Ltd | Construction | 2003 |
| Agate Property Limited | Real estate | 2021 |
| Ahmeds Taxis Ltd | Transport & logistics | 2026 |
| AHN Ltd | Information & communication | 2016 |
| Ainsheen Limited | Wholesale & retail | 2021 |
| Air Plumbing & Heating Ltd | Construction | 2018 |
| AIS (Marine) 2 Limited | Administrative & support | 2013 |
| AJ Sussex Limited | Construction | 2024 |
| AKD Consulting Ltd | Professional & scientific | 2010 |
| AKM Accountancy Limited | Professional & scientific | 2014 |
| AKM Accountants Ltd | Extraterritorial | 2015 |
| Akmd Medical Services Limited | Health & social care | 2015 |
| AL Hodhod Limited | Information & communication | 2008 |
| Alatus Management Ltd | Professional & scientific | 2016 |
| Albany Bidco Limited | Professional & scientific | 2022 |
| Albert PJV Consulting Ltd | Other services | 2018 |
| Albion Business Computers Limited | Information & communication | 1997 |
| Albion Travel Solutions Limited | Transport & logistics | 2019 |
| Alcantara Properties Limited | Real estate | 2016 |
| Alchemy by Effect Doctors Limited | Public administration | 2019 |