| A-Line Building & Carpentry Ltd | Construction | 2024 |
| A-Storage Limited | Real estate | 2013 |
| A-Z Business & Transport Ltd | Transport & logistics | 2018 |
| A-Z Property Marketers Ltd | Real estate | 2025 |
| A-Z Skazka Ltd | Wholesale & retail | 2012 |
| A-Z-Care Ltd | Health & social care | 2019 |
| A. Clayton-Payne & Co Limited | Wholesale & retail | 2010 |
| A. Hartnell Marine Electrical Ltd | Manufacturing | 2015 |
| A. Lambert Flat Management Limited | Real estate | 1972 |
| A.C.A.Building Ltd | Construction | 2025 |
| A.D. Metal Spinners Limited | Manufacturing | 1973 |
| A.E. Adams (Estates) Limited | Construction | 2023 |
| A.J. Thomas Properties Ltd | Real estate | 2004 |
| A.J.D Conversions Ltd | Construction | 2019 |
| A.M.R. Products Limited | Wholesale & retail | 1999 |
| A.R Connected Ltd | Administrative & support | 2024 |
| A.R. Aviation Limited | Professional & scientific | 2011 |
| A.R.M Technologies Limited | Information & communication | 2023 |
| A.T. Medical Ltd | Wholesale & retail | 2010 |
| A.Taylor Electrical Contracting Limited | Construction | 2023 |
| A.Ti Marine Limited | Manufacturing | 2022 |
| A.V. Ridout (Highcliffe) Limited | Real estate | 1978 |
| A.W. Electrical Contractors & Engineers Limited | Construction | 2001 |
| A1 Hire and Sales Limited | Extraterritorial | 2025 |
| A1 Home Renovations Ltd | Construction | 2019 |
| A1 Parkwood Engineering Ltd | Transport & logistics | 2015 |
| A2G Limited | Other services | 2019 |
| A2HF Limited | Administrative & support | 2024 |
| A7 Commodities Limited | Wholesale & retail | 2019 |
| AA Carpentry Projects Limited | Construction | 2022 |
| AA Civils Ltd | Construction | 2021 |
| AA Scaffolding Limited | Construction | 2015 |
| AAA Building Contractors Ltd | Construction | 2023 |
| AAA Building Ltd | Construction | 2024 |
| AAA Supplements Ltd | Wholesale & retail | 2022 |
| AAL Distributions Ltd | Wholesale & retail | 2026 |
| Aamb Ltd | Wholesale & retail | 2021 |
| AAP Investments Limited | Hospitality | 2016 |
| AAP Management Group Limited | Real estate | 2020 |
| AAP Residential Limited | Real estate | 2023 |
| Aarav Global IT Solutions Ltd | Information & communication | 2026 |
| Aardvark Residential Services Ltd | Households | 2022 |
| Aargh Ltd | Wholesale & retail | 2025 |
| Aashvi Foods Ltd | Hospitality | 2024 |
| AB & DS Properties Ltd | Real estate | 2020 |
| AB Barwari Ltd | Hospitality | 2025 |
| AB Facial Aesthetics Ltd | Health & social care | 2012 |
| AB Freehold Limited | Real estate | 2007 |
| AB Transport Removals & Storage Ltd | Transport & logistics | 2023 |
| Abacie Beta Limited | Real estate | 2022 |
| Abacie Gamma Limited | Real estate | 2023 |
| Abacie Limited | Real estate | 2020 |
| Abacus Care Solutions Ltd | Health & social care | 2017 |
| Abacus Consultancy (Bournemouth) Ltd | Professional & scientific | 2025 |
| Abacus Removals Limited | Transport & logistics | 2021 |
| Abba Care Limited | Health & social care | 2016 |
| Abbey Close Management (Curry Rivel) Limited | Households | 1992 |
| Abbey Developments Southern Limited | Construction | 2009 |
| Abbey Freeholders Limited | Other services | 2017 |
| Abbey Models Limited | Wholesale & retail | 2000 |
| Abbeydale New Bone China Co. Ltd | Professional & scientific | 2010 |
| Abbeyfield Wessex Society Limited | Hospitality | 1963 |
| ABBEYTOYS2003 Limited | Extraterritorial | 2009 |
| Abbot's Court Farm(Charborough) | Agriculture & fishing | 1967 |
| Abbots Court Dorset Limited | Administrative & support | 2019 |
| Abbots Services Limited | Construction | 2024 |
| Abbotswood Academy Ltd | Education | 2023 |
| Abbotswood Day Nursery Limited | Health & social care | 2009 |
| Abbotswood Romsey Ltd | Real estate | 2025 |
| Abbotts Property Group Ltd | Real estate | 2025 |
| Abcde Hub Ltd | Education | 2022 |
| Abcleaning & Maintenance Ltd | Construction | 2024 |
| Abellus Group Ltd | Construction | 2020 |
| Aberdeen One Energy Limited | Professional & scientific | 2024 |
| Abes Marine Limited | Manufacturing | 2022 |
| Abhi Investments Limited | Real estate | 2018 |
| Abhi Stores Limited | Wholesale & retail | 2012 |
| Abhiroh Limited | Health & social care | 2022 |
| ABI Electrical Design Limited | Professional & scientific | 2023 |
| Abilil Limited | Construction | 2007 |
| Ability Transport Limited | Transport & logistics | 2009 |
| Abis Business Services Limited | Real estate | 2021 |
| Abis One Limited | Real estate | 2003 |
| Abis Property Investments Limited | Real estate | 2022 |
| ABK Online Services Limited | Wholesale & retail | 2020 |
| ABL Trade Ltd | Wholesale & retail | 2017 |
| Able BOB Services Limited | Extraterritorial | 2018 |
| ABM Drainage Ltd | Other services | 2023 |
| ABM Plumbing & Heating Limited | Construction | 2026 |
| Abney Property Solutions Ltd | Administrative & support | 2005 |
| About Heating Limited | Construction | 2017 |
| Above & Beyond Property Solutions Limited | Construction | 2020 |
| Above Board Marine Limited | Other services | 2003 |
| Above the Divot Limited | Construction | 2008 |
| ABQ Global Ltd | Hospitality | 2024 |
| ABQ Grand Palace & Spa Ltd | Hospitality | 2020 |
| ABQ Hermitage Hotel Ltd | Hospitality | 2018 |
| ABQ Hospitality & Property Management UK Ltd | Hospitality | 2021 |
| ABQ Hospitality Management Ltd | Hospitality | 2023 |
| ABQ Investment UK Ltd | Hospitality | 2014 |