| A-Z Project Services Limited | Professional & scientific | 2003 |
| A. C. Webb Facility Services Limited | Manufacturing | 2016 |
| A. J. Joinery Limited | Manufacturing | 1999 |
| A. J. Laminated Beams Limited | Manufacturing | 2001 |
| A. Valiant Holdings Limited | Financial services | 2019 |
| A.D. Thomas Trading Ltd | Wholesale & retail | 2022 |
| A.Ego Ltd | Information & communication | 2024 |
| A.G.A.P Ltd | Wholesale & retail | 2025 |
| A.Gutauskas Limited | Transport & logistics | 2026 |
| A.Jasuitis Ltd | Transport & logistics | 2025 |
| A.M Collection Ltd | Real estate | 2021 |
| A.M. Analytics Incorporated Limited | Information & communication | 2025 |
| A.M. Promech Ltd | Financial services | 2020 |
| A.Mazeika Limited | Transport & logistics | 2026 |
| A.Nutautas Ltd | Transport & logistics | 2024 |
| A.Racinskij Ltd | Transport & logistics | 2025 |
| A.T. Veterinary Systems Limited | Information & communication | 1992 |
| A.Vibriantis Limited | Transport & logistics | 2026 |
| A1 Cars (Suffolk) Ltd | Transport & logistics | 2011 |
| A1 Flat Pack Assembly Service Ltd | Professional & scientific | 2023 |
| A1 Premier Solutions Limited | Other services | 2014 |
| A14 Cars Limited | Transport & logistics | 2025 |
| A14 IT Services Ltd. | Information & communication | 2024 |
| A14K Ltd | Information & communication | 2024 |
| A25M Limited | Financial services | 2025 |
| A2B Car Rent Ltd | Administrative & support | 2024 |
| A2B Creations Ltd | Wholesale & retail | 2022 |
| A2B Taxi Services (Newmarket) Limited | Transport & logistics | 2009 |
| A2B Wholesale Ltd | Wholesale & retail | 2026 |
| A2D Electrical Limited | Construction | 2021 |
| A2SV IT Services Ltd | Information & communication | 2021 |
| A2Y Productions Ltd | Information & communication | 2025 |
| A2Z Freight Ltd | Transport & logistics | 2021 |
| A300 Ltd | Transport & logistics | 2026 |
| A3DP Limited | Manufacturing | 2023 |
| A3O Ltd | Information & communication | 2024 |
| A4 Autos Ltd | Wholesale & retail | 2024 |
| A9 Motors Ltd | Wholesale & retail | 2025 |
| AA Courier Services NW Ltd | Transport & logistics | 2025 |
| AA Steel Detailing Ltd | Professional & scientific | 2024 |
| Aaditya Medical Locums Ltd | Health & social care | 2013 |
| Aadya Advisory Ltd | Professional & scientific | 2026 |
| Aahmz Limited | Wholesale & retail | 2026 |
| AAI MAA Ltd | Wholesale & retail | 2022 |
| Aakesh Property Ltd | Real estate | 2025 |
| Aamrl Ltd | Wholesale & retail | 2020 |
| Aarviation Ltd | Information & communication | 2013 |
| AAS Airfield Solutions Limited | Professional & scientific | 2022 |
| Aavta International Limited | Real estate | 2024 |
| AB Continental Ltd | Construction | 2022 |
| AB PT Limited | Arts & recreation | 2026 |
| AB Reclamation Ltd | Wholesale & retail | 2022 |
| Abacus Clothing Ltd | Wholesale & retail | 2025 |
| Abacus Kitchens Ltd | Construction | 2023 |
| ABB Consulting Ltd | Administrative & support | 2025 |
| Abbey Chiropractic Limited | Health & social care | 2008 |
| Abbey Glass (Holdings) Limited | Construction | 2023 |
| Abbey Labels Limited | Manufacturing | 1987 |
| Abbey Lane Properties Limited | Construction | 2018 |
| Abbey West Commercial Property Limited | Real estate | 2010 |
| Abbeyfields (Bury ST Edmunds) Residents Management Company Ltd | Households | 2012 |
| Abbeygate Accountancy Holdings Ltd | Financial services | 2021 |
| Abbeygate Accountancy Ltd | Professional & scientific | 2013 |
| Abbeygate Cinema Limited | Information & communication | 2014 |
| Abbeygate Construction Ltd | Construction | 2012 |
| Abbeygate Groundworks Ltd | Construction | 2015 |
| Abbeygate Investments Limited | Financial services | 2022 |
| Abbeygate Wealth Management Limited | Administrative & support | 2009 |
| Abbeygate WM Properties Ltd | Real estate | 2019 |
| Abbeyscape Landscaping and Driveways Limited | Administrative & support | 2025 |
| Abbot Road Management Company Limited | Households | 2003 |
| Abbots Bridge Reclamation Limited | Wholesale & retail | 1999 |
| Abbotsford Park (NO. 1) Residents Association Limited | Households | 2002 |
| Abbotsford Park (NO.2) Residents Association Limited | Households | 2003 |
| Abbotsford Park (NO.3) Residents Association Limited | Professional & scientific | 2003 |
| Abbotsgate Investments Limited | Real estate | 2014 |
| Abbottluxe Properties Limited | Real estate | 2021 |
| Abbrey & Reece Limited | Construction | 2006 |
| Abbyola Ltd | Health & social care | 2018 |
| ABC Childcare Centre SR Ltd | Education | 2018 |
| ABC Cleaning Midlands Ltd | Administrative & support | 2020 |
| ABC Management Ltd | Administrative & support | 2011 |
| ABCS1 Ltd | Administrative & support | 2026 |
| ABD Trading Group Ltd | Wholesale & retail | 2018 |
| Abdel-Moniem IT Services Ltd | Information & communication | 2014 |
| Abdr Ltd | Arts & recreation | 2010 |
| Abdul Haque Ltd | Wholesale & retail | 2025 |
| ABE & Sons Limited | Real estate | 2024 |
| Abed Psychiatry Ltd | Health & social care | 2026 |
| Abergele EYE Care Limited | Health & social care | 2025 |
| Abglp Group Ltd | Financial services | 2023 |
| Abishola Group Limited | Wholesale & retail | 2024 |
| Able Education Ltd | Education | 2024 |
| Abml GP Ltd | Health & social care | 2020 |
| Abna Isaac Ltd | Information & communication | 2018 |
| Abode Projects Ltd | Professional & scientific | 2013 |
| Abolytix Limited | Information & communication | 2025 |
| Above Accounting Ltd | Administrative & support | 2019 |
| Abrey Caddick Limited | Wholesale & retail | 2020 |
| Abroadline UK Ltd | Professional & scientific | 2023 |