| AM Flooring Installations Ltd | Construction | 2025 |
| Amadeus Consulting Limited | Professional & scientific | 2023 |
| Amanda Long Consulting Limited | Professional & scientific | 2005 |
| Amarinth Limited | Manufacturing | 2002 |
| Ambertek Limited | Information & communication | 1995 |
| Amcas Corporation Ltd | Information & communication | 2006 |
| Ametech Automotive Ltd | Wholesale & retail | 2019 |
| AMF Vault Ltd | Financial services | 2024 |
| AMS Tech Ltd | Manufacturing | 2008 |
| Anders Modeling Ltd | Professional & scientific | 2022 |
| Anderson Kitchens & Bathrooms Ltd | Construction | 2009 |
| Andrew Pritchard Limited | Professional & scientific | 2017 |
| Andrew Wardlaw Project Solutions Ltd | Information & communication | 2018 |
| Andy Smith Plumbing and Heating Limited | Construction | 2018 |
| Angels & Demons Tattoo and Piercing Ltd | Arts & recreation | 2025 |
| Anglesey Fuels Ltd | Wholesale & retail | 2012 |
| Anglia Locums Ltd | Professional & scientific | 2012 |
| Anglia Passive House Ltd | Construction | 2016 |
| Anglia Recliners Limited | Manufacturing | 2005 |
| Anglia Sporting Activities Limited | Arts & recreation | 2001 |
| Anglia Trading Ltd | Professional & scientific | 2021 |
| Anglo Mechanical Limited | Construction | 2017 |
| Ansdell Services Ltd | Real estate | 1996 |
| Anticks Limited | Wholesale & retail | 2014 |
| Antique Collectors' Club Limited (the) | Information & communication | 1971 |
| Ap&D Group Ltd | Real estate | 2022 |
| Apex Building & Plumbing Ltd | Construction | 2026 |
| Apex Nest Ltd | Real estate | 2025 |
| Apollo Five Limited | Real estate | 2010 |
| Aposphere Ltd | Professional & scientific | 2015 |
| Applebuild Limited | Wholesale & retail | 2005 |
| AQ Wiring Systems Rockford Ltd | Manufacturing | 1984 |
| AR Commercials Limited | Wholesale & retail | 2024 |
| Arable Farm Services Limited | Transport & logistics | 1996 |
| Aras Fries Ltd | Hospitality | 2020 |
| ARB East Tree Services Limited | Agriculture & fishing | 2017 |
| ARC Agronomic Sciences Ltd | Agriculture & fishing | 2024 |
| Arcarsfram Ltd | Transport & logistics | 2024 |
| Ardleys (Eastwood) Properties Limited | Real estate | 1962 |
| Areola Restoration Tattoo CIC | Other services | 2025 |
| Argo Mediterranean Holdings Ltd | Extraterritorial | 2023 |
| Arlingtons (Ipswich) Ltd | Real estate | 2018 |
| Arlo IT Limited | Information & communication | 2021 |
| Arraius Limited | Professional & scientific | 2024 |
| Art for Cure | Administrative & support | 2016 |
| Art for Cure Enterprises Ltd | Administrative & support | 2015 |
| Art Safari Limited | Administrative & support | 2003 |
| ART-S2 Limited | Professional & scientific | 2013 |
| Ascalon Canine Care Limited | Other services | 2022 |
| ASH Corporate Finance (Altnagelvin) Limited | Real estate | 2004 |
| ASH Corporate Finance (Canterbury) Ltd | Administrative & support | 2003 |
| ASH Corporate Finance (Hampstead) Limited | Real estate | 2003 |
| ASH Corporate Finance (Maidstone) Limited | Administrative & support | 2001 |
| ASH Corporate Finance (Suffolk) Limited | Administrative & support | 2006 |
| ASH Corporate Finance Limited | Professional & scientific | 1995 |
| ASH Grove Property Ltd | Real estate | 2026 |
| Ashe Chimney Sweep Anglia Ltd | Administrative & support | 2025 |
| Ashenden Architecture Ltd | Professional & scientific | 2015 |
| Ashwood Homes (Suffolk) Ltd | Construction | 2025 |
| Asteria Wellbeing Ltd | Other services | 2022 |
| Astraea Productions Ltd | Information & communication | 2020 |
| Astron Property Partners Limited | Real estate | 2020 |
| AT Autoworks Ltd | Wholesale & retail | 2024 |
| Atelier Project Management Limited | Information & communication | 2004 |
| Athena Properties & Developments Ltd | Real estate | 2024 |
| Athena Tech Limited | Professional & scientific | 2002 |
| Atkinson Property Limited | Real estate | 2018 |
| Atlas (Chimney Sweep) Ltd | Administrative & support | 2003 |
| Attain Digital Ltd | Professional & scientific | 2021 |
| Attain Solutions Ltd | Professional & scientific | 2017 |
| Attwood Sydney Holdings Limited | Real estate | 2014 |
| Audium Solutions Limited | Administrative & support | 2010 |
| Aurora Accountancy & Tax Ltd | Professional & scientific | 2009 |
| Aurora Nova Limited | Agriculture & fishing | 2012 |
| Autovision Windscreens Management Limited | Wholesale & retail | 2007 |
| Aviex Digital Ltd | Wholesale & retail | 2024 |
| Avocet Mews Management Company Limited | Real estate | 1999 |
| Avocet Properties Limited | Construction | 2009 |
| Axen Limited | Transport & logistics | 1983 |
| AZ Plumbing Services Limited | Construction | 2020 |
| AZF Limited | Professional & scientific | 2026 |
| B Chocolates (Suffolk) Ltd | Manufacturing | 2016 |
| BAC Woodbridge Limited | Construction | 2011 |
| Badingham Community Cafe C.I.C. | Hospitality | 2016 |
| Badingham Playschool C.I.C. | Education | 2021 |
| Bagson Property Ltd | Real estate | 2019 |
| Bailie Ventures Limited | Professional & scientific | 2017 |
| Baines Surveying Services Limited | Professional & scientific | 2006 |
| Baker & King Ltd | Construction | 2016 |
| Balfour Chapman Ltd | Professional & scientific | 2025 |
| Banjax Limited | Hospitality | 2025 |
| Banyard & Houchell Limited | Wholesale & retail | 1954 |
| Barley Green Garage Ltd | Wholesale & retail | 2025 |
| Barmann Services Limited | Hospitality | 2023 |
| Barnards Butchers Limited | Other services | 2017 |
| Barncourt Ltd | Wholesale & retail | 2011 |
| Barnes & Gable Ltd | Real estate | 2021 |
| Barney Newman Limited | Information & communication | 2010 |
| Barone Consulting Limited | Construction | 2023 |
| Barrett’S Electrical Ltd | Construction | 2018 |