| Aponic International Ltd | Agriculture & fishing | 2017 |
| Aponic Ltd | Agriculture & fishing | 2014 |
| Appendix Productions Limited | Professional & scientific | 2001 |
| Approved Engines Ltd | Wholesale & retail | 2022 |
| Approved Repair and MOT Centre Ltd Ltd | Wholesale & retail | 2025 |
| Apter Bros Ltd | Real estate | 2022 |
| ARC Building & Construction Ltd | Construction | 2019 |
| Arcbrow Developments Ltd | Construction | 2025 |
| Architectural Management Ltd | Professional & scientific | 2015 |
| Archive Storage and Retrieval Limited | Construction | 1999 |
| Archplace Property Management Limited | Professional & scientific | 1995 |
| Ardyn Limited | Financial services | 2024 |
| ARK Wines Ltd | Agriculture & fishing | 2024 |
| Armstrong INK Limited | Manufacturing | 2016 |
| Aromatherapet Ltd | Manufacturing | 2025 |
| Arrowsmith Engineering and Consultants Limited | Professional & scientific | 1981 |
| Artechulate UK Ltd | Information & communication | 2017 |
| Artificial Rush Ltd | Information & communication | 2025 |
| AS Blasting and Coatings Limited | Manufacturing | 2015 |
| ASB Shiny Hand Car Wash Ltd | Other services | 2024 |
| Ashen Manufacturing Support Limited | Professional & scientific | 2003 |
| Ashfield Holdings Limited | Real estate | 2016 |
| Ashfield Homes (Suffolk) Limited | Construction | 2016 |
| Ashlea Court RTM Company Limited | Households | 2009 |
| Aspc Holdings Limited | Financial services | 2019 |
| Aspect Projects Ltd | Construction | 2026 |
| Asphalt, Building & Construction Limited | Construction | 2022 |
| Aspiring Properties Ltd | Real estate | 2019 |
| Asset Manufacturing Limited | Construction | 1984 |
| Assington Fruits Limited | Agriculture & fishing | 2005 |
| Assist Consulting (Essex) Ltd | Professional & scientific | 2014 |
| Aston Court Limited | Households | 2003 |
| Aston LEY Limited | Professional & scientific | 2019 |
| Atherton Court Residents Association Limited | Households | 2021 |
| Atstone Memorials Limited | Manufacturing | 2019 |
| Auberies Estate (Holdings) Limited | Financial services | 2013 |
| Auberies Estate (Property) Limited | Construction | 2013 |
| Auberies Estate Farms Limited | Agriculture & fishing | 1964 |
| Auberies Estate Sporting Limited | Arts & recreation | 2023 |
| Audio Lease (Cambridge) Ltd | Administrative & support | 2014 |
| Audio Plus Limited | Administrative & support | 2016 |
| Audiolease (Equipment) Limited | Administrative & support | 2013 |
| Audiolease Limited | Administrative & support | 2014 |
| Aunty Ree's Cookies and More Ltd | Manufacturing | 2025 |
| Auria Innovations Ltd | Manufacturing | 2025 |
| Aurum Collectibles Ltd | Wholesale & retail | 2025 |
| Auto Innovations (Sudbury) Limited | Professional & scientific | 2011 |
| Automotion Diagnostics Limited | Wholesale & retail | 2025 |
| Automotion Service Centre Limited | Wholesale & retail | 2020 |
| Automotion Vehicle Engineering Limited | Wholesale & retail | 2012 |
| Autonex Ltd | Professional & scientific | 2024 |
| Auxilio Support Limited | Administrative & support | 2019 |
| AV Control Limited | Information & communication | 2003 |
| AV4U (Trading AS ADD Vantage 4 U) Limited | Professional & scientific | 2019 |
| AVA Tech Lighting Ltd | Construction | 2024 |
| Avacum Services Ltd | Construction | 2023 |
| Avan Property Limited | Construction | 2020 |
| Avian Developments Limited | Real estate | 2005 |
| Aviland Limited | Manufacturing | 2012 |
| Avoncroft Mews Management Company Limited | Households | 2004 |
| Azra Hairdresser Ltd | Other services | 2024 |
| B & H Properties (Sudbury) LLP | | 2018 |
| B J Accountancy Services Limited | Professional & scientific | 2017 |
| B K & Co Developments Ltd | Construction | 2025 |
| B-Space Ltd | Wholesale & retail | 2016 |
| B.E Sealed Ltd | Construction | 2022 |
| Babooco Limited | Extraterritorial | 1997 |
| Baby Box Limited | Wholesale & retail | 2015 |
| Back to Wilderness Ltd | Education | 2021 |
| Backfox Limited | Information & communication | 2018 |
| Baddow Wood Limited | Real estate | 2026 |
| Bakers Court Cornard Freehold Limited | Households | 2018 |
| Bakers Mill Management Company Limited | Households | 1986 |
| Baldwin Alarms Limited | Administrative & support | 2018 |
| Ballingdon Grove Hotel Limited(The) | | 1986 |
| Ballingdon Hall Ltd | Wholesale & retail | 2021 |
| Ballingdon Hall Trading Ltd | Wholesale & retail | 2026 |
| Banga Traders Limited | Wholesale & retail | 2026 |
| Banhoek Chilli OIL Company (UK) Ltd | Wholesale & retail | 2018 |
| Barbers Specialist Waterproofing Limited | Construction | 2023 |
| Barker & Stone Holdings Ltd | Financial services | 2025 |
| Barker & Stone Ltd | Hospitality | 2021 |
| Barker James Limited | Extraterritorial | 2017 |
| Barker,Barker&Stone Ltd | Manufacturing | 2023 |
| Barking Central Management Company (NO.2) Limited | Households | 2007 |
| Barking Central Management Company Limited | Households | 2006 |
| Barks & Bangs Ltd | Other services | 2025 |
| Barks & Pals - Doggy Daycare Ltd | Other services | 2025 |
| Barrells Green Builders Limited | Construction | 2020 |
| Barrett’S Groundwork & Civil Engineering Ltd | Construction | 2024 |
| Barrow Property Group Ltd | Real estate | 2024 |
| Base Construction Chemicals Industry UK Limited | Construction | 2022 |
| Bass Energy Ltd | Professional & scientific | 2018 |
| Bastable House Freehold Company Ltd | Households | 2013 |
| Bastable House Property Management Company Limited | Households | 2012 |
| Bates Wells & Braithwaite Limited | Professional & scientific | 2012 |
| Bavarian Property Development Ltd | Manufacturing | 2023 |
| Baxters' Consulting Services Limited | Professional & scientific | 2018 |
| BB GAS Heating and Plumbing Ltd | Construction | 2023 |
| BCD Crystal Limited | Information & communication | 2026 |