| AB FAB Events Limited | Other services | 2012 |
| AB Initio Project Management Limited | Construction | 2010 |
| AB Smart Union Advisers Ltd | Construction | 2019 |
| AB Sport Psychology Limited | Health & social care | 2024 |
| Abacus Estate Holdings Limited | Real estate | 2017 |
| Abacus Facilities Management Ltd | Other services | 2020 |
| Abbentis Limited | Information & communication | 2017 |
| Abbey Landscape (Norfolk) Limited | Construction | 2017 |
| Abdul's Cuisine Limited | Hospitality | 2018 |
| Abingworth Vineyard LLP | | 2021 |
| Abld Lettings Ltd | Real estate | 2023 |
| ABM Comms Ltd | Professional & scientific | 2023 |
| ABORT67 Limited | Education | 2012 |
| Above Board Fixings Limited | Construction | 2004 |
| Abracadabra Day Nursery Limited | Health & social care | 2014 |
| Absolute 22 Ltd | Real estate | 2022 |
| Absolute Landrovers Ltd | Wholesale & retail | 2023 |
| ABU K Tech Solution Ltd | Information & communication | 2026 |
| Abundance Hill Ltd | Professional & scientific | 2008 |
| Abuttle Ltd | Information & communication | 2025 |
| AC Brothers Ltd | Wholesale & retail | 2025 |
| AC Electrics and General Building Ltd | Construction | 2022 |
| AC Tech Solutions Ltd | Information & communication | 2016 |
| Ac's Landscaping and Maintenance Services Ltd. | Administrative & support | 2017 |
| Acacia House and Garden Mews Worthing Ltd. | Households | 2021 |
| Academy of Creative Training Ltd | Arts & recreation | 2005 |
| Accelerated Performance Solutions Ltd | Professional & scientific | 2021 |
| Access Taxis Limited | Administrative & support | 2009 |
| Accompanied Building Check Limited | Construction | 2015 |
| Accountancy Recruitment Consultants Limited | Administrative & support | 1997 |
| Accounting Hub Limited | Professional & scientific | 2023 |
| Accouve Limited | Extraterritorial | 2008 |
| Accubooks Ltd | Professional & scientific | 2010 |
| Accutax Solutions (South Coast) Ltd | Professional & scientific | 2020 |
| Accutax Solutions Ltd | Professional & scientific | 2023 |
| Ace Building Services Essex Ltd | Construction | 2021 |
| Ace Car Hire (Worthing) Limited | Transport & logistics | 1972 |
| Ace Fones Limited | Wholesale & retail | 2004 |
| Ace Grading Limited | Administrative & support | 2021 |
| Ace House Ltd | Households | 2007 |
| Ace Kebab Limited | Hospitality | 2024 |
| Ace Wall Ties Limited | Administrative & support | 2001 |
| Ace Wheels Ltd | Wholesale & retail | 2012 |
| Acecutter Limited | Professional & scientific | 1978 |
| ACG Logistic Ltd | Transport & logistics | 2019 |
| Aclipse Electrical Group Ltd | Construction | 2021 |
| Acorn Care Services Limited | Health & social care | 1997 |
| Acorn Improvements Limited | Construction | 1996 |
| Acorn Pregnancy Counselling Centre Limited | Health & social care | 2002 |
| Acquivision Limited | Information & communication | 1994 |
| Acre Care Ltd | Other services | 2005 |
| Acronym Computers Ltd | Information & communication | 2010 |
| Actie Limited | Information & communication | 2026 |
| Actipro Energy Ltd. | Professional & scientific | 2010 |
| ACTIV8 Nursery Henfield Limited | Health & social care | 2018 |
| Active Pump Services Ltd | Other services | 1998 |
| Active Trade Point Limited | Construction | 2018 |
| Active Worthing Wellbeing Centre CIC | Education | 2020 |
| Acumen Property and Maintenance Ltd | Construction | 2026 |
| AD Retail and Services Ltd | Wholesale & retail | 2024 |
| Ad-Int Limited | Professional & scientific | 2019 |
| Adam Dumbrill Limited | Financial services | 2021 |
| Adam Fahey Design Ltd | Construction | 2005 |
| Adam Hayes Electrical Limited | Administrative & support | 2010 |
| Adam Morris Communications Limited | Professional & scientific | 2006 |
| Adam Property Management (South) Limited | Wholesale & retail | 2017 |
| Adam Simmonds Consultant Limited | Professional & scientific | 2018 |
| Adams One Stop Shop Ltd | Real estate | 2010 |
| Adams Online Store Ltd | Hospitality | 2020 |
| Adams Wholesale (Southampton) Ltd | Wholesale & retail | 2020 |
| Adams Wholesale (West Sussex) Limited | Wholesale & retail | 2006 |
| Adams Wholesale Enterprises Ltd | Wholesale & retail | 2010 |
| Adams Wholesale Food Service Ltd | Wholesale & retail | 2012 |
| Adams Wholesale Meats Ltd | Wholesale & retail | 2017 |
| Adams Wholesale Southern Group Ltd | Wholesale & retail | 2013 |
| Adams Wholesale Surrey Ltd | Wholesale & retail | 2020 |
| Adaptec Mobility Ltd | Construction | 2019 |
| Adclinic Ltd | Professional & scientific | 2025 |
| Addon Construction Project Management Ltd | Construction | 2021 |
| Adebis Ltd | Wholesale & retail | 2026 |
| Adelphi Systems Limited | Professional & scientific | 1998 |
| Adeshokan Ltd | Arts & recreation | 2021 |
| Adester Trading Limited | Professional & scientific | 2011 |
| ADH IFA Ltd | Professional & scientific | 2014 |
| ADH Prime Foods Limited | Hospitality | 2022 |
| ADI Trans 2020 Ltd | Transport & logistics | 2020 |
| ADJ Maintenance Limited | Construction | 2010 |
| ADJ Property Management Limited | Real estate | 2009 |
| Adnele Ltd | Real estate | 2026 |
| Adorable Care Ltd | Health & social care | 2026 |
| ADP Engineering Services Ltd | Professional & scientific | 2018 |
| Adrian Jones Ltd | Construction | 2013 |
| Adrian Oliver & Co Limited | Administrative & support | 2000 |
| Adscapes Limited | Administrative & support | 2016 |
| Adsin Limited | Wholesale & retail | 2021 |
| Adur and Worthing Food Partnership CIC | Hospitality | 2025 |
| Adur Bangladeshi Muslim Society | Other services | 2015 |
| Adur Estates Limited | Construction | 2025 |
| Adur Home Improvements Limited | Construction | 1998 |
| Adur Pest Control Limited | Administrative & support | 2023 |