| Alta VIA Consulting Limited | Administrative & support | 2017 |
| Altogether Properties Limited | Real estate | 2011 |
| Alturon Limited | Professional & scientific | 2025 |
| Ambient Tone Limited | Professional & scientific | 2018 |
| Ambition Brand Support Ltd. | Professional & scientific | 2005 |
| AMG Bespoke Catering Ltd | Hospitality | 2021 |
| AMH Holdings Limited | Real estate | 2025 |
| Amity Arborists Ltd | Agriculture & fishing | 2013 |
| AN Fabrications Limited | Manufacturing | 2014 |
| Anakoko Limited | Professional & scientific | 2017 |
| Analytical Discoveries Limited | Information & communication | 2018 |
| Anderson and Scott Furniture Ltd | Other services | 2023 |
| Anderson and Scott Holdings Ltd | Construction | 2023 |
| Andrew Gray Project Management Ltd | Construction | 2024 |
| Angel Nails (North) Limited | Other services | 2015 |
| Angle Consultants Limited | Administrative & support | 2016 |
| Anglia Assessment Limited | Education | 2003 |
| Anglia Business Park Limited | Real estate | 2020 |
| Anglia Church Trust | Other services | 2002 |
| Anglia Cleaning Solutions Ltd | Administrative & support | 2012 |
| Anglia Concrete Finishing Ltd | Construction | 2025 |
| Anglian Agri Media Limited | Professional & scientific | 2014 |
| Animalsfirst Wholesale Ltd | Wholesale & retail | 2024 |
| Anna Morgan MBE Limited | Professional & scientific | 2021 |
| Anon Ltd | Real estate | 2022 |
| Antan Limited | Wholesale & retail | 2024 |
| Antechs (Support Services) Limited | Administrative & support | 2012 |
| AP & AP Building Services Limited | Construction | 2019 |
| Apex Education Alternative Provision Ltd | Education | 2024 |
| Apmp Consulting Services Limited | Administrative & support | 2018 |
| Apollo Pharma Solutions Limited | Professional & scientific | 2017 |
| Appletree Value Solutions Limited | Professional & scientific | 2016 |
| Applewhite Property Investments Limited | Real estate | 2022 |
| Applewhites Furniture Limited | Manufacturing | 2003 |
| Aqua Ace Limited | Administrative & support | 2025 |
| Aqua Blue Trading Limited | Real estate | 2022 |
| AR Strategy Consulting Limited | Professional & scientific | 2020 |
| Arboreal Associates Limited | Agriculture & fishing | 2026 |
| Arbtalk Media Ltd | Professional & scientific | 2017 |
| ARC Tree Surgery Limited | Agriculture & fishing | 2009 |
| Arcoli Properties Limited | Real estate | 2025 |
| ARJ Welding & Fabrication Ltd | Manufacturing | 2026 |
| ARK Services (Itee) Ltd | Professional & scientific | 2024 |
| Arkouda Ltd | Professional & scientific | 2018 |
| Arms Consulting Limited | Wholesale & retail | 2011 |
| Art Intelligence Limited | Professional & scientific | 2026 |
| Asbecruit Limited | Administrative & support | 2019 |
| Asbestos Assist Limited | Education | 2023 |
| Ascentech Ltd | Hospitality | 2026 |
| Ashco International Limited | Real estate | 2018 |
| Aslay Limited | Hospitality | 2024 |
| Aspals Limited | Wholesale & retail | 2023 |
| Aspen Direct Ltd | Extraterritorial | 2025 |
| Aspire Together CIC | Health & social care | 2011 |
| Assessment and Services Innovation Ltd | Health & social care | 2017 |
| Asset Control Anglia Ltd | Administrative & support | 2023 |
| Asset Worth Limited | Real estate | 2022 |
| Aston Architectural Steel Limited | Construction | 2020 |
| Astral Fields Ltd | Information & communication | 2026 |
| Astraquest Limited | Information & communication | 2024 |
| AT Tomorrow's Company Ltd | Information & communication | 2025 |
| Atclg Ltd | Information & communication | 2019 |
| Atec Solutions Limited | Information & communication | 1997 |
| Athena Project Management Limited | Information & communication | 2022 |
| Atkinsons Consultancy Limited | Professional & scientific | 2020 |
| Aurelia Limited | Education | 1999 |
| Auriel Homes Limited | Real estate | 2006 |
| Aurora Events Hire Ltd | Hospitality | 2025 |
| Auroralets Ltd | Real estate | 2022 |
| Austin Motor Company Ltd | Manufacturing | 2015 |
| Austinallen Limited | Professional & scientific | 2005 |
| Auto Electrics (Bacton) Ltd | Wholesale & retail | 2023 |
| Auto Perfection (EA) Limited | Wholesale & retail | 2005 |
| Autocross Limited | Wholesale & retail | 2002 |
| Avant Electronics Group Ltd | Financial services | 2023 |
| Avant Electronics Ltd | Wholesale & retail | 2012 |
| Avant Property Investments Ltd. | Real estate | 2022 |
| Avanta Facilities Management Limited | Water & waste | 2016 |
| Avanta Waste Solutions Limited | Extraterritorial | 2025 |
| AW Freight UK Ltd | Transport & logistics | 2026 |
| AW Witczak Ltd | Transport & logistics | 2026 |
| AYM Events Limited | Administrative & support | 2016 |
| B R J Courier Ltd | Transport & logistics | 2020 |
| B&M Clearances Limited | Transport & logistics | 2020 |
| B. Samson Builders Limited | Construction | 2001 |
| B. W. Projects Limited | Construction | 2020 |
| B.W. Developments Limited | Real estate | 2000 |
| Babutsa Limited | Hospitality | 2025 |
| Baby Point Limited | Manufacturing | 1994 |
| Bacton Pigs Limited | Agriculture & fishing | 1976 |
| Bacton Solutions Ltd | Administrative & support | 2004 |
| Baker Family Holdings Limited | Financial services | 2016 |
| Baldwin Home Improvements Ltd | Construction | 2024 |
| Baldwins Garden Centre Concessions Ltd | Wholesale & retail | 2019 |
| Baldwins of Stowmarket Ltd | Wholesale & retail | 2022 |
| Balfour One Limited | Real estate | 2025 |
| Ballingdon Developers Limited | Construction | 2023 |
| Baltic Bear Group Ltd | Wholesale & retail | 2022 |
| Bambrough Limited | Financial services | 2025 |
| Bar Solutions Inc. | Hospitality | 2003 |