| Angela Dellar Ltd | Professional & scientific | 2009 |
| Angelic Care Resourcing Ltd | Administrative & support | 2018 |
| Anglia Aggregates Limited | Water & waste | 2026 |
| Anglia Mould Tools Limited | Manufacturing | 2002 |
| Anglia Valves & Controls Limited | Administrative & support | 2014 |
| Anglian Property Ltd | Real estate | 2025 |
| Anjisha Studio Ltd | Wholesale & retail | 2025 |
| Annabel Brown Architect Limited | Professional & scientific | 2022 |
| Annies Homecare Services Ltd | Health & social care | 2013 |
| Annunciation Press Limited | Arts & recreation | 2023 |
| ANR Property Services Ltd | Construction | 2023 |
| Anstruther Hair & Beauty Limited | Other services | 2013 |
| Antares Finance Limited | Administrative & support | 2024 |
| Anthony Holdings Limited | Construction | 2018 |
| Antiques by Design Limited | Manufacturing | 2001 |
| Anytime 24 Ltd | Transport & logistics | 2025 |
| AOB Projects London Limited | Real estate | 2017 |
| Apex Alliance International Limited | Professional & scientific | 2023 |
| Apex Capital Wealth Limited | Professional & scientific | 2024 |
| Apex Contracting Solutions Ltd | Construction | 2022 |
| Apex Garden Plants Limited | Professional & scientific | 2000 |
| APM Pool Care Ltd | Administrative & support | 2018 |
| Apollo Multiserve Ltd | Administrative & support | 2017 |
| Applizmo Limited | Extraterritorial | 2019 |
| Appropriate Development Consultants Limited | Real estate | 1996 |
| Aqua Worx Plumbing & Heating Limited | Construction | 2021 |
| Aquaculture Limited | Wholesale & retail | 2023 |
| Aquaphot Limited | Extraterritorial | 1989 |
| Aquasport Limited | Arts & recreation | 2004 |
| AR Ceramic Tiling Limited | Construction | 2023 |
| AR Design and Build Ltd | Construction | 2022 |
| AR Electrical Services Group Ltd | Construction | 2022 |
| Aragbeks Ltd | Professional & scientific | 2021 |
| Arbour Engineering Limited | Manufacturing | 1969 |
| ARC Flooring Limited | Administrative & support | 2015 |
| Archer Property Services Limited | Real estate | 2015 |
| Archers Pest Control Ltd | Other services | 2019 |
| Ardent Estates Ltd | Real estate | 2013 |
| Argent Court Estates Ltd | Real estate | 2016 |
| Argent Street "a" Management Company Limited | Real estate | 1986 |
| Argent Street 'B' Management Company Limited | Real estate | 1986 |
| Arkitek Design Limited | Professional & scientific | 2023 |
| Armtech Consulting Limited | Information & communication | 2020 |
| Arnold Transport Limited | Wholesale & retail | 2023 |
| Arrow Security Shutters Ltd | Construction | 2001 |
| Art Esprit Limited | Education | 1995 |
| Art G Property Ltd | Real estate | 2021 |
| Artac Logistics Limited | Professional & scientific | 2011 |
| Artimate Ltd | Education | 2018 |
| Aruna Property Limited | Real estate | 2018 |
| Asadul (Service) Limited | Other services | 1986 |
| Asadul Investments Ltd | Financial services | 2023 |
| Asante Hiking Limited | Extraterritorial | 2020 |
| Ascension Scaffolding Limited | Construction | 2010 |
| Ashley Ellis Construction Limited | Construction | 2018 |
| Asian Snacks Ltd | Manufacturing | 2014 |
| ASL Autism Assessment Ltd | Health & social care | 2025 |
| Aspen Atlantic Limited | Professional & scientific | 1997 |
| Aspen Building Solutions Ltd | Construction | 2025 |
| Aspire Customer Communications Services Ltd. | Professional & scientific | 2015 |
| Aspris Media Ltd | Information & communication | 2025 |
| Assecure Limited | Wholesale & retail | 2011 |
| Asset Valuation and Sales Limited | Administrative & support | 2018 |
| Associated Glazing Services Limited | Construction | 2014 |
| Assured Business Compliance Ltd | Administrative & support | 2025 |
| Ataylored Therapy Ltd | Health & social care | 2025 |
| Athena Contractors Limited | Construction | 2010 |
| Atlantic Pacific Group Limited | Professional & scientific | 2000 |
| Atlantic Pacific International Limited | Professional & scientific | 2017 |
| Atlantic Pacific Limited | Professional & scientific | 2000 |
| Atlantic Pacific Travel Limited | Professional & scientific | 2014 |
| Atlantic Square Management Limited | Households | 2004 |
| Atlas Autocare Limited | Wholesale & retail | 2025 |
| Atlas Autos Limited | Wholesale & retail | 2012 |
| Atlas Furniture International Ltd | Wholesale & retail | 2015 |
| Atrium Asset Management Limited | Real estate | 2012 |
| Atrium Healthcare Communications Limited | Administrative & support | 2003 |
| Atrium Residential Investments Ltd | Real estate | 2013 |
| Attwood Consultancy Ltd | Information & communication | 2015 |
| Audio Morphology Limited | Information & communication | 1994 |
| Augers Limited | Extraterritorial | 1981 |
| August & Sage Ltd | Real estate | 2025 |
| Aurelio Guitars Ltd | Manufacturing | 2024 |
| Aurora Salons Limited | Other services | 2014 |
| Auto Grand Ltd | Wholesale & retail | 2019 |
| Auto Smart and Detail Limited | Wholesale & retail | 2023 |
| AVA Homes Renovations Limited | Construction | 2022 |
| Avaustin Holdings Limited | Financial services | 2025 |
| Awtuk Ltd | Construction | 2025 |
| AZ Aerosports Ltd | Arts & recreation | 2017 |
| AZ Premier Properties Ltd | Real estate | 2020 |
| Azure Plate Ltd | Hospitality | 2025 |
| B & C Newman Services Limited | Construction | 2015 |
| B & C Property (Essex) Limited | Real estate | 2020 |
| B P Designs Ltd | Professional & scientific | 2009 |
| B W Cutters Limited | Financial services | 2005 |
| B.A.H Racing Ltd | Wholesale & retail | 2021 |
| B.E Home Improvements Limited | Construction | 2025 |
| B3NCH Limited | Information & communication | 2025 |
| Back Then Emporium Ltd | Wholesale & retail | 2026 |