| A&G Marine Carpentry Ltd | Manufacturing | 2022 |
| A&I Select Ltd | Transport & logistics | 2026 |
| A&K Smedtrans Ltd. | Transport & logistics | 2025 |
| A&M Contract Solutions Limited | Administrative & support | 2026 |
| A&N Addis Holdings Ltd | Construction | 2022 |
| A&P Wojcik Limited | Wholesale & retail | 2018 |
| A&S Veterans Bike Tours & Events Ltd | Administrative & support | 2025 |
| A&T Fisherious Limited | Hospitality | 2025 |
| A-Road Properties Ltd | Real estate | 2023 |
| A-Spec Car Sales Ltd | Wholesale & retail | 2020 |
| A-Tech Services Limited | Information & communication | 2003 |
| A-Z Yachting Ltd | Administrative & support | 2019 |
| A. Mainstone Ltd | Construction | 2006 |
| A.C. Neal Limited | Construction | 2003 |
| A.C.L Holdings Ltd | Administrative & support | 2019 |
| A.E.C. (South West) Electrical Limited | Construction | 1988 |
| A.E.T. Plumbing & Heating Services Limited | Construction | 2012 |
| A.G Plastering & Render Ltd | Construction | 2025 |
| A.G.Jessopp Limited | Construction | 1961 |
| A.G.S. Sailing Limited | Arts & recreation | 2004 |
| A.H. Castle Keep Ltd | Construction | 2021 |
| A.H. JV Ltd | Construction | 2019 |
| A.H.G. BH13 Ltd | Construction | 2022 |
| A.H.G. North Dorset Developments Ltd | Construction | 2021 |
| A.H.G. Poole Developments 1 Ltd | Construction | 2022 |
| A.H.G. Poole Developments Ltd | Construction | 2022 |
| A.J. Developments (Barton Common) Limited | Real estate | 2017 |
| A.J. Developments Limited | Construction | 2010 |
| A.M Collectible Ltd | Wholesale & retail | 2026 |
| A.M.B. Developments Limited | Construction | 1999 |
| A.T. & G. Datanet Limited | Information & communication | 1991 |
| A1 Brothers Ltd | Wholesale & retail | 2025 |
| A1 Care Property Ltd | Households | 2023 |
| A1 Healthcare Group Ltd | Health & social care | 2025 |
| A1 Home Care Services Ltd | Health & social care | 2021 |
| A1 Service Centre Ltd | Wholesale & retail | 2014 |
| A24 Vision Ltd | Transport & logistics | 2022 |
| A2Z ALL Trading UK Ltd | Wholesale & retail | 2021 |
| A3A Energy Ltd | Professional & scientific | 2021 |
| A3DIGITAL Ltd | Information & communication | 2026 |
| A4B Medical Ltd | Education | 2024 |
| A7 Draffan Limited | Energy | 2010 |
| A7 Energy Ltd | Construction | 2003 |
| A7 Greendykeside Limited | Energy | 2005 |
| A7 Lochhead Limited | Energy | 2006 |
| AA & OO Limited | Wholesale & retail | 2008 |
| AA Taylor Medical Consulting Ltd | Education | 2012 |
| Aahilscraft&Co Ltd | Wholesale & retail | 2024 |
| Aaif Ashir Ltd | Wholesale & retail | 2025 |
| Aamirsaba Ltd | Wholesale & retail | 2021 |
| Aardvark Dormant Accounts Limited | Information & communication | 2025 |
| Aaro Glass Ltd | Construction | 2003 |
| Aaron Consulting Limited | Information & communication | 2007 |
| Aasp Group UK (Automotive) Ltd | Wholesale & retail | 2018 |
| AB Engineering Dorset Limited | Professional & scientific | 2018 |
| AB Gregory Ltd | Administrative & support | 2024 |
| AB Properties (Poole) Ltd | Real estate | 2022 |
| AB25 Consultancy Ltd | Professional & scientific | 2025 |
| Abacus AP Ltd | Wholesale & retail | 2018 |
| Abacus Construction (Bournemouth) Limited | Real estate | 1993 |
| Abacus Developments Bmth Ltd | Construction | 2015 |
| Abacus UK Holdings Ltd | Financial services | 2018 |
| Abax Consulting Ltd | Information & communication | 2024 |
| Abbas Cabins Limited | Water & waste | 2005 |
| Abbas Holdings Ltd | Professional & scientific | 2020 |
| Abbascombe Ltd | Construction | 2025 |
| Abbasisolutions Ltd | Information & communication | 2025 |
| Abbey (Southern) Ltd | Manufacturing | 2003 |
| Abbey Lodge (Residential Home) Ltd | Health & social care | 2003 |
| Abbey Supply Company Limited | Manufacturing | 1995 |
| Abbie and DAD Design Limited | Wholesale & retail | 2023 |
| Abbotsbury Services Limited | Professional & scientific | 2003 |
| Abbott Video Forensics Ltd | Administrative & support | 2021 |
| Abbott's Meadow Management Company Limited | Households | 2000 |
| ABC Agency Limited | Administrative & support | 2022 |
| ABC Project Solutions Ltd | Information & communication | 2024 |
| Abdul Discounts Ltd | Wholesale & retail | 2025 |
| Abdul Rehman Mubashar Cheema Ltd | Wholesale & retail | 2025 |
| Abdulsami Group Ltd | Wholesale & retail | 2025 |
| Abexpress BIS Ltd | Transport & logistics | 2021 |
| Abi's Analytics Ltd | Information & communication | 2017 |
| Abid Group Limited | Wholesale & retail | 2025 |
| Abingdon Investments Limited | Real estate | 1984 |
| Able Lifting Equipment (Southern) Limited | Manufacturing | 1990 |
| Able Training & Consultancy Ltd | Education | 2024 |
| Ablepa Limited | Other services | 2019 |
| ABN AC Limited | Professional & scientific | 2018 |
| ABN Housing Limited | Real estate | 2018 |
| Abnglobal Limited | Wholesale & retail | 2025 |
| Abode Impact Limited | Real estate | 2017 |
| Abogear Limited | Wholesale & retail | 1997 |
| About Results Ltd | Professional & scientific | 2021 |
| Above and Beyond Services Limited | Manufacturing | 2016 |
| Above Need Ltd | Education | 2022 |
| Abraham & BEN Hadar Law and Audit Ltd | Wholesale & retail | 2022 |
| Abrtnmedia Ltd | Wholesale & retail | 2022 |
| ABS Absolutely Best Service Limited | Wholesale & retail | 2020 |
| Absolute Building Supplies Ltd | Wholesale & retail | 2018 |
| Absolute Gifts Ltd | Wholesale & retail | 2020 |
| Absolute Maintenance SW Ltd | Construction | 2026 |