| 67 Cottage Grove Residents Limited | Households | 2021 |
| 7 Bar and Restaurant Ltd | Hospitality | 2022 |
| 71 Church Road Management Company Limited | Households | 1995 |
| 73 Kingston Road Limited | Households | 2017 |
| 8 ST Andrews Road RTM Company Limited | Households | 2010 |
| 80 Marmion Road Limited | Households | 2021 |
| 83 Victoria Road South Management Company Limited | Real estate | 2017 |
| 85 Marmion Road Limited | Households | 2012 |
| 89 Victoria Road South Limited | Households | 2008 |
| 89-91 Castle Road (Management Company) Limited | Real estate | 2013 |
| 9 & 11 Salisbury Road Freehold Limited | Households | 2012 |
| 9 Nightingale Road Company Limited | Extraterritorial | 2014 |
| 93 Tangier Road Limited | Real estate | 2018 |
| 99-101 Highland Road Ltd | Extraterritorial | 2014 |
| A & B Motors Limited | Wholesale & retail | 2010 |
| A & S Fleets Ltd | Administrative & support | 2024 |
| A & S Hughes Limited | Wholesale & retail | 2011 |
| A Cube Services Ltd | Administrative & support | 2025 |
| A Fistful of Dice Ltd | Wholesale & retail | 2014 |
| A Parnell Ltd | Real estate | 2025 |
| A R Taylor Electrical Services Ltd | Construction | 2013 |
| A Rigby Limited | Information & communication | 2023 |
| A Sterling Landscapes Ltd | Administrative & support | 2026 |
| A W Nash Ltd | Other services | 2025 |
| A&D Gaming Ltd | Information & communication | 2025 |
| A&L Decorating Oxford Holding Limited | Construction | 2022 |
| A. Corp Ltd | Information & communication | 2018 |
| A.L.L Decorating &Property Services Ltd | Construction | 2016 |
| A.M. Global Visa & Hospitality Limited | Administrative & support | 2021 |
| A.S Booth & Family Heavy Haulage Ltd | Transport & logistics | 2022 |
| A1 Residentials Ltd | Real estate | 2024 |
| A1 Rose Estate Ltd | Real estate | 2024 |
| A1 Speedy Recovery Ltd | Transport & logistics | 2024 |
| A1 Taxi Hire Ltd | Transport & logistics | 2024 |
| A17 Services Ltd | Administrative & support | 2023 |
| A3 Decorators Limited | Construction | 2012 |
| A3 Marrakesh Food Ltd | Hospitality | 2023 |
| A3 Project Management Ltd | Real estate | 2022 |
| AAA Crew Ltd | Arts & recreation | 2011 |
| AAA Digital Services Limited | Wholesale & retail | 2026 |
| Aald Limited | Other services | 2017 |
| Aasiyahomes Ltd | Hospitality | 2025 |
| AAT Commercials Ltd | Real estate | 2025 |
| AB Business Systems Limited | Construction | 2012 |
| AB Electronics Limited | Construction | 2026 |
| AB Wealth Ltd | Financial services | 2017 |
| Abbeville Management Limited | Households | 2020 |
| Abdullahsultan Ltd | Wholesale & retail | 2026 |
| Abnx Ltd | Information & communication | 2008 |
| ABP Consultancy Services Limited | Administrative & support | 2015 |
| Absolute Shutters UK Ltd | Construction | 2014 |
| AC Groundworks & Landscaping Ltd | Construction | 2024 |
| AC Southern Properties Limited | Real estate | 2016 |
| AC Southsea Management Ltd | Households | 2023 |
| Acad Developments Limited | Construction | 2024 |
| Accountancy Expertise Limited | Administrative & support | 1996 |
| Accounts & Payroll Training Ltd | Information & communication | 2003 |
| Accudo House Limited | Hospitality | 2017 |
| Accudo Investments Limited | Financial services | 2005 |
| Accurate Construction Limited | Construction | 2017 |
| Accurate Property Investments Limited | Real estate | 2023 |
| Achieve Health Limited | Health & social care | 2025 |
| Acquired Solutions Ltd | Real estate | 2013 |
| Acronym Voip Ltd | Information & communication | 2023 |
| ACS Auto Sales Ltd | Wholesale & retail | 2026 |
| ACT of Kindness Organics Ltd | Manufacturing | 2018 |
| Actiondisk Limited | Information & communication | 1988 |
| ACTIV8 Global (UK) Ltd | Information & communication | 2024 |
| Active Imaan Ltd | Wholesale & retail | 2025 |
| Adam K Electrical Services Limited | Construction | 2015 |
| Adam Ventures Limited | Extraterritorial | 2012 |
| Admiral Square Management Company Limited | Real estate | 2007 |
| Admirals (Southsea) Management Company Limited | Households | 1989 |
| ADP Computing Solutions Ltd | Wholesale & retail | 2021 |
| Adriatic Adventures Ltd | Administrative & support | 2024 |
| ADS Cleaning & Restoration Ltd | Administrative & support | 2026 |
| Adski Composites Ltd | Other services | 2016 |
| Adspace Ltd. | Professional & scientific | 2017 |
| Adzee Limited | Other services | 2019 |
| Aerial Dance Academy Ltd | Arts & recreation | 2024 |
| Aesthetic Business Transformations Limited | Professional & scientific | 2014 |
| Aesthetic Wellness Clinic Ltd | Other services | 2025 |
| Afficiant Investments Ltd | Real estate | 2020 |
| Affino Creative Media Ltd | Arts & recreation | 2025 |
| Affordable Motor Glass Ltd | Wholesale & retail | 2007 |
| Afghan Community and Education Centre Ltd | Education | 2022 |
| Afnowra Limited | Wholesale & retail | 2026 |
| Afro Frontiers Limited | Wholesale & retail | 2019 |
| Afshar Blunsom Ltd | Health & social care | 2019 |
| Agcmhealth Limited | Public administration | 2019 |
| Agency Studio Ltd | Professional & scientific | 2026 |
| Aggregate Consultants & Security Services Ltd | Administrative & support | 2016 |
| Agon Distribution Limited | Wholesale & retail | 2018 |
| AGS Electrical Division Ltd | Construction | 2025 |
| AHA Engineering Limited | Manufacturing | 2021 |
| Ahead Technologies Limited | Construction | 2013 |
| Ahmed Brothers Holdings Limited | Financial services | 2026 |
| Ahmed Travel Services Ltd | Administrative & support | 2018 |
| Aiga Construction Ltd | Construction | 2015 |
| Aiminghigh Consulting Ltd | Professional & scientific | 2024 |