| (IIM) Immersive Media CIC | Administrative & support | 2024 |
| 110 ST Georges Road Limited | Real estate | 2006 |
| 118 Go Ltd | Information & communication | 2011 |
| 17.2 Development Studios Ltd | Other services | 2018 |
| 178 Camden Road Freehold Ltd | Extraterritorial | 2016 |
| 1964 Venture Ltd | Hospitality | 2018 |
| 279 Dyke Road Residents Association Company Limited | Households | 1985 |
| 2810 Productions Ltd | Arts & recreation | 2018 |
| 29 Old Shoreham Road Management Limited | Households | 2025 |
| 2B Nourished Ltd | Other services | 2020 |
| 33 Waldegrave Road Ltd | Hospitality | 2014 |
| 3SD Ventures Ltd | Professional & scientific | 2018 |
| 41 Norroy Road Ltd | Households | 2004 |
| 43A Bear Road Ltd | Real estate | 2025 |
| 48 Springfield Road Limited | Real estate | 2017 |
| 4AE Limited | Health & social care | 2023 |
| 4R Building Limited | Construction | 2007 |
| 5 Wykeham Terrace Brighton (Management) Limited | Real estate | 2003 |
| 56 High Street Ltd | Real estate | 2015 |
| 5985 Ltd | Administrative & support | 2025 |
| 5ML Limited | Construction | 2023 |
| 717BROS Ltd | Wholesale & retail | 2025 |
| 83-85 High Street Hurst Right to Manage Company Limited | Households | 2025 |
| 84 Buckingham Road Brighton Limited | Households | 2010 |
| 87 High Street Hurst Right to Manage Company Limited | Households | 2025 |
| 87 South Coast Road Ltd | Real estate | 2017 |
| A D Construction & Development Limited | Construction | 2014 |
| A D Properties (Southern) Limited | Construction | 2016 |
| A Doctrove Consulting Limited | Professional & scientific | 2026 |
| A Happier Year Ltd | Information & communication | 2022 |
| A Hint of Lemon Ltd | Extraterritorial | 2017 |
| A J Brickcutters Chimneys Limited | Manufacturing | 2017 |
| A J Ross Limited | Manufacturing | 2003 |
| A&H Medical Limited | Health & social care | 2018 |
| A. C.A. Property Limited | Real estate | 2004 |
| A. D. Cycles Limited | Other services | 2017 |
| A.C.A. Scaffolding Limited | Construction | 1998 |
| Aajaa Limited | Real estate | 2024 |
| Aaron David Estates Limited | Real estate | 2025 |
| Aaron's Tyres Limited | Wholesale & retail | 2026 |
| Abidi Oral Care Ltd | Health & social care | 2025 |
| Ability Promotions 2022 Limited | Other services | 2022 |
| Absolute Beauty (Sussex) Ltd | Other services | 2015 |
| AC Investment Properties Ltd | Real estate | 2017 |
| Accept & Proceed Limited | Professional & scientific | 2007 |
| Ackers Scaffolding & Plant Hire Ltd | Construction | 2009 |
| Acorn Fasteners Limited | Wholesale & retail | 2010 |
| Acres 4 Dogs Ltd | Administrative & support | 2010 |
| Acuity Digital Services Limited | Information & communication | 2014 |
| Acumen Enterprise Ltd | Real estate | 2024 |
| Adam Fitzpatrick Ltd | Wholesale & retail | 2016 |
| Adastra Visions Ltd | Real estate | 2015 |
| Adeline Tyler Ltd | Wholesale & retail | 2024 |
| Adikt Limited | Professional & scientific | 2021 |
| ADM Estates Ltd | Real estate | 2016 |
| ADM Property Group Ltd | Real estate | 2011 |
| Adorawool Limited | Wholesale & retail | 2017 |
| ADR Contractors Ltd | Construction | 2018 |
| ADUR2ARUN Property Management Limited | Real estate | 2024 |
| Advanced Restorative Care Limited | Health & social care | 2015 |
| Advanced Training Designs Limited | Other services | 2014 |
| Adventure Go Limited | Hospitality | 2025 |
| Aegean Seafoods Limited | Wholesale & retail | 2017 |
| Aerials and Data Installations Ltd | Construction | 2018 |
| Affinity Creates Limited | Information & communication | 2025 |
| AG Contact Centres Ltd | Health & social care | 2019 |
| AG Family Support Ltd. | Health & social care | 2015 |
| Agas Consultancy Limited | Other services | 2025 |
| AGE Concern - Hassocks & District | Health & social care | 2005 |
| AHD Property Rentals Ltd | Real estate | 2022 |
| AHZ Cars Ltd | Wholesale & retail | 2025 |
| Air Cruise (Holdings) Ltd | Administrative & support | 2023 |
| Airstream Design Consultancy Limited | Professional & scientific | 2019 |
| Ajlsp Holdings Ltd | Professional & scientific | 2025 |
| AKA Growth Ltd | Information & communication | 2025 |
| Akacode Technologies Limited | Information & communication | 2007 |
| AKD Property Rentals Ltd | Real estate | 2022 |
| Akrmelm Limited | Information & communication | 2025 |
| Albany Homes Northside Limited | Construction | 2026 |
| Albourne Cars Limited | Wholesale & retail | 2023 |
| Albourne Village Show CIC | Administrative & support | 2024 |
| Alec Stevens Coaching Ltd | Health & social care | 2023 |
| Alex Page Personal Training Ltd | Other services | 2010 |
| Alex Playback Please Limited | Information & communication | 2025 |
| Alexandra Taylor Hairdressing Ltd | Other services | 2010 |
| Alfie Hughes & Co Ltd | Wholesale & retail | 2026 |
| Alkin Books Limited | Information & communication | 1992 |
| ALL Wines Ltd | Wholesale & retail | 2008 |
| Allclear House Clearance Limited | Transport & logistics | 2024 |
| Allwoods (Hassocks) Limited | Agriculture & fishing | 2011 |
| Alphapet UK Ventures Limited | Financial services | 2021 |
| ALPIC22 Ltd | Professional & scientific | 2022 |
| Alta Premises Limited | Hospitality | 2022 |
| Altitude Associates Limited | Administrative & support | 2000 |
| Amplified Travel Services Ltd | Administrative & support | 2021 |
| AN Concepts Ltd | Wholesale & retail | 2025 |
| Analytical Business Consulting Ltd | Information & communication | 2018 |
| Andrew JJ Properties Ltd | Real estate | 2019 |
| Andrew Thatcher & Co Limited | Real estate | 2026 |
| Angeldust (UK) Limited | Real estate | 2002 |