| Adventurous Life and Leadership Ltd | Professional & scientific | 2023 |
| Adventurous Machines Limited | Professional & scientific | 2015 |
| Advocom Property Ltd | Real estate | 2025 |
| Advrt Consulting Ltd | Other services | 2015 |
| Advrt Marketing Limited | Professional & scientific | 2017 |
| AE (Southern) Limited | Construction | 2025 |
| AE Racking Installations Ltd | Construction | 2015 |
| AEC Recruitment Ltd | Administrative & support | 2025 |
| Aedis Group Ltd | Construction | 2026 |
| AEE Consulting Ltd | Professional & scientific | 2023 |
| AEF Solutions Limited | Professional & scientific | 2001 |
| Aegean Cleaning Services Ltd | Administrative & support | 2021 |
| Aegis Alarms Limited | Manufacturing | 2010 |
| Aegis ALL Care Limited | Health & social care | 2026 |
| Aegis Concerns Limited | Health & social care | 2015 |
| Aegis Family Care Limited | Health & social care | 2018 |
| AEI Electronics Limited | Extraterritorial | 2011 |
| AEL Scaffolding Solutions Limited | Construction | 2020 |
| Aero Sense Technologies Holdings Limited | Manufacturing | 2015 |
| Aero Sense Technologies Limited | Manufacturing | 2008 |
| Aero Taxis Southampton Ltd | Transport & logistics | 2013 |
| Aero Technics (Manchester) Limited | Manufacturing | 2010 |
| Aerodyne Europe UAV Ltd | Information & communication | 2017 |
| Aeropark Developments Limited | Construction | 1989 |
| Aeroprints Limited | Administrative & support | 2011 |
| Aerosstech Ltd | Manufacturing | 2025 |
| Aerotherm Solutions Limited | Construction | 2025 |
| Aerotrac Limited | Information & communication | 2011 |
| Aerovantage Limited | Administrative & support | 2026 |
| Aesop Research Ltd | Information & communication | 2021 |
| Aesthetic House Limited | Real estate | 2021 |
| Aesthetica Atelier Ltd | Other services | 2025 |
| Aesthetics by Bloom Ltd | Other services | 2025 |
| Aesthetics Championship Limited | Health & social care | 2024 |
| Aesthetics Unlocked Limited | Arts & recreation | 2023 |
| Aether Aviation Detailing Ltd | Administrative & support | 2025 |
| AF Grounds & Fencing Ltd | Construction | 2025 |
| AF Legacy Developers Ltd | Real estate | 2026 |
| AF the Full Deck Limited | Construction | 2026 |
| Afaan Travel & Tour Ltd | Administrative & support | 2026 |
| Afan Properties Limited | Real estate | 2026 |
| Afbk Ltd | Public administration | 2025 |
| AFC Marine Consultants & Surveyors Ltd | Manufacturing | 2017 |
| AFC Totton 1886 Limited | Arts & recreation | 2018 |
| AFC Totton DP Limited | Education | 2025 |
| AFC Totton Leisure Limited | Real estate | 2014 |
| AFD Innovation CAD Technology Ltd | Manufacturing | 2025 |
| AFE Software Ltd | Information & communication | 2002 |
| AFF Property Ltd | Real estate | 2020 |
| Affektive Limited | Other services | 2013 |
| Affinity Financial Network U.K. Limited | Information & communication | 2002 |
| Affinity Protect Limited | Financial services | 2018 |
| Affirm Homes Ltd | Real estate | 2019 |
| Affirm Property Services Ltd | Real estate | 2019 |
| Affizer Ltd | Information & communication | 2025 |
| Affordable Doors and Windows Ltd | Construction | 2026 |
| Affricardo Ltd | Other services | 2013 |
| Afghan Bakery Southampton Ltd | Manufacturing | 2025 |
| Afghan Groceries Ltd | Manufacturing | 2025 |
| Afghan Star Bakery Ltd | Manufacturing | 2024 |
| Afloat Marine Services Ltd | Manufacturing | 2005 |
| AFM International Ltd | Wholesale & retail | 2025 |
| AFP Plus Limited | Professional & scientific | 2005 |
| African Activities C.I.C. | Education | 2018 |
| African Beauty Fashion Shop Limited | Wholesale & retail | 2021 |
| African Savannah Consulting Limited | Professional & scientific | 2022 |
| Africanpantry Ltd | Hospitality | 2024 |
| Africaspire CIC | Education | 2025 |
| Afrikwu Limited | Wholesale & retail | 2024 |
| Afritopia Limited | Hospitality | 2012 |
| Afro City Limited | Wholesale & retail | 2015 |
| Afro Delight Ltd | Hospitality | 2024 |
| Afro Heights Ltd | Wholesale & retail | 2024 |
| Afrosteps Global Ltd | Administrative & support | 2025 |
| AFS Developments Limited | Construction | 2019 |
| AFS Lettings Ltd | Real estate | 2023 |
| Aftab Hire Ltd | Transport & logistics | 2010 |
| After Builders Commercial Solution Ltd | Other services | 2015 |
| Afterdrk Ltd | Wholesale & retail | 2023 |
| Afterglow Heating Limited | Construction | 2017 |
| AG GR Flooring Limited | Construction | 2014 |
| AG Martial Arts Academy CIC | Arts & recreation | 2025 |
| AGA Sandhu Ltd | Other services | 2021 |
| Agam Care Ltd | Health & social care | 2015 |
| AGB Trading Ltd | Wholesale & retail | 2010 |
| AGD Contractors Ltd | Real estate | 2024 |
| AGE Concern Hampshire Corporate Trustee Limited | Other services | 2013 |
| AGE Concern New Forest | Health & social care | 1999 |
| AGE Repair 2022 Limited | Health & social care | 2021 |
| AGE Repair Ltd | Health & social care | 2016 |
| Ageas Bowl Experience Limited | Arts & recreation | 2008 |
| Agency Assist Limited | Professional & scientific | 2024 |
| Agentimiseai Limited | Information & communication | 2002 |
| Agga Solution Limited | Information & communication | 2023 |
| Aggies Food Ltd | Hospitality | 2017 |
| Aghnablaney Farming Co Ltd | Real estate | 2004 |
| Agile Carpentry Ltd | Manufacturing | 2018 |
| Agile SD Ltd | Information & communication | 2014 |
| Agile Software Solutions Ltd | Wholesale & retail | 2016 |
| AGK Anglia Limited | Professional & scientific | 2022 |