| 87 Marineside Limited | Real estate | 2022 |
| 87-91 Picardy Road (DA17) Freehold Limited | Households | 2025 |
| 888 Holdings Ltd | Real estate | 2019 |
| 9-13 Winders Road Limited | Households | 2010 |
| 95-101 Westbourne Grove LLP | | 2010 |
| 9DESIGN Services Ltd | Professional & scientific | 2016 |
| A Pearson Holdings Limited | Professional & scientific | 2008 |
| A & D Catering Solutions Limited | Hospitality | 2013 |
| A & D H R Consultancy Limited | Professional & scientific | 2006 |
| A & G Developments (Southern) Ltd | Construction | 2026 |
| A & G Welding and Erection Ltd | Construction | 2023 |
| A & K Hancock Limited | Construction | 2016 |
| A & P Group Holdings Limited | Financial services | 2017 |
| A . T Storage Ltd | Administrative & support | 2021 |
| A 1 Cosmetic Development Ltd | Professional & scientific | 2024 |
| A Davies Removals Limited | Transport & logistics | 2002 |
| A G Mcbride Brickwork and General Building Limited | Construction | 2004 |
| A Head Space Limited | Other services | 2020 |
| A J Murrell Sales Limited | Wholesale & retail | 2009 |
| A J W Development Limited | Construction | 2007 |
| A New Beginning Properties Ltd | Administrative & support | 2024 |
| A P D Electrical Limited | Construction | 2021 |
| A Pearson Growers Limited | Agriculture & fishing | 2008 |
| A Phillips Electrical Ltd | Construction | 2024 |
| A Place Called Home Ltd | Households | 2015 |
| A R Bryer Limited | Construction | 2008 |
| A S Marsh Ltd | Professional & scientific | 2020 |
| A Sereda Limited | Health & social care | 2020 |
| A Shore Holiday Ltd | Hospitality | 2023 |
| A W Garage Door & Repairs Ltd | Construction | 2013 |
| A&A Prepare Ltd | Manufacturing | 2017 |
| A&E Plumbing and Drainage Sussex Ltd | Construction | 2024 |
| A&M Haberdashery&Fabrics Limited | Wholesale & retail | 2022 |
| A&P Investing Ltd | Real estate | 2019 |
| A-Fab Signs Limited | Professional & scientific | 2014 |
| A-Star Finishing Ltd | Manufacturing | 2021 |
| A. E. Parker Ltd | Extraterritorial | 2021 |
| A.C Electrical Contractors Ltd | Construction | 2006 |
| A.G. Langham & Sons Limited | Construction | 1998 |
| A.I.M.S. Precision Ltd. | Administrative & support | 1996 |
| A.P.S. Salads Limited | Wholesale & retail | 2006 |
| A.S.M. Carpentry & Joinery Limited | Construction | 2014 |
| A1 Build Cleaning Limited | Administrative & support | 2018 |
| A1 Carpet Cleaning Portsmouth Ltd | Other services | 2020 |
| A1 Carpet Cleaning West Sussex Ltd | Other services | 2019 |
| A1 Projects Limited | Real estate | 2003 |
| A1 Sales and Installation Ltd | Wholesale & retail | 2023 |
| A2Z Confectionery Ltd | Wholesale & retail | 2025 |
| AA Contractors Southern Limited | Construction | 2024 |
| AAB Healthcare Limited | Health & social care | 2017 |
| Aari & Zari Ltd | Professional & scientific | 2013 |
| Aaron Bradbury Plumbing & Heating Limited | Construction | 2020 |
| Aarya UK PVT Ltd | Wholesale & retail | 2025 |
| Aaryas Gourmet Kitchen Limited | Hospitality | 2023 |
| AB FAB Cleaners Ltd | Health & social care | 2026 |
| Abantwana Limited | Real estate | 2024 |
| Abbeville Investments Ltd | Financial services | 2023 |
| Abbeyfield Chichester Society Ltd(The) | Hospitality | 1961 |
| Abbott Fencing Limited | Construction | 2022 |
| Abbott Motor Services Ltd | Wholesale & retail | 2022 |
| Abbotts Acres Limited | Real estate | 2025 |
| ABC Architectural Services Limited | Financial services | 2021 |
| ABC Events (UK) Limited | Arts & recreation | 2013 |
| Aberfeldy Consultancy Services Ltd | Professional & scientific | 2026 |
| Aberfeldy Property Services Ltd | Professional & scientific | 2026 |
| Ability Software Ltd | Information & communication | 2022 |
| Abmh Structures Limited | Professional & scientific | 2017 |
| Above ALL Landscaping Ltd | Administrative & support | 2024 |
| Absfba Ltd | Wholesale & retail | 2026 |
| Absolute Design Consultancy Limited | Professional & scientific | 2000 |
| Absolutely Fabulous Boutique Limited | Wholesale & retail | 2025 |
| Absolutesport.As Ltd | Education | 2018 |
| ABT Plastering Limited | Construction | 2007 |
| AC Plumbing & Props Ltd | Construction | 2021 |
| Acacia JA Holdings Limited | Financial services | 2026 |
| Acara Limited | Other services | 2023 |
| ACC Tyres Limited | Manufacturing | 2012 |
| Accomplish Care Chichester Ltd | Health & social care | 2024 |
| Accomplish CMS Ltd | Information & communication | 2008 |
| Accudda Ltd | Information & communication | 2025 |
| Ace Aggregates (Chichester) Ltd | Construction | 2026 |
| Ace Construction (Sussex) Ltd | Construction | 2019 |
| Ace Decorations & Refurbishments Ltd | Construction | 2018 |
| Ace Furnishing Limited | Wholesale & retail | 2002 |
| Ace Green Recycling UK Ltd | Manufacturing | 2022 |
| Ace Pro Recruitment Ltd | Administrative & support | 2024 |
| Ace Property Management & Lettings Ltd | Real estate | 2023 |
| Ace Taxis (Bognor) Limited | Transport & logistics | 2023 |
| Ace Town Ltd | Wholesale & retail | 2017 |
| Acenti Ltd | Professional & scientific | 2016 |
| ACHIEVE2GETHER Limited | Administrative & support | 2022 |
| Acid Marketplace Ltd | Administrative & support | 2013 |
| ACM Finances Limited | Financial services | 2021 |
| Acme Legal Limited | Professional & scientific | 2017 |
| Acorn International Distribution Limited | Professional & scientific | 2014 |
| Acorn Labs Limited | Professional & scientific | 2019 |
| Acquaria Ltd | Wholesale & retail | 2020 |
| Acre Estates & Investments Ltd | Real estate | 2024 |
| Across Safety Development Ltd | Administrative & support | 2015 |
| ACS Performance Improvement Limited | Professional & scientific | 2006 |