| Always There Domiciliary Care Limited | Health & social care | 2019 |
| AMA Scaffolding Limited | Construction | 2011 |
| Amarka Aluminium Limited | Manufacturing | 2017 |
| AMB Double Glazing Repair Ltd | Manufacturing | 2023 |
| Ambisite Solutions Limited | Construction | 2024 |
| AMC Motors Ltd | Wholesale & retail | 2022 |
| AMG Incorporate Ltd | Construction | 2024 |
| AMG North Weald Limited | Transport & logistics | 1979 |
| AMJ Property Investments Limited | Real estate | 2018 |
| Amor Decor Ltd | Wholesale & retail | 2019 |
| Amroz & Aaroz Investments Limited | Real estate | 2025 |
| AMS Admin Group Ltd | Professional & scientific | 2023 |
| AMS Admin Support Services Limited | Professional & scientific | 2020 |
| ANA Trade UK Ltd | Wholesale & retail | 2018 |
| Anderson's Retail Ltd | Wholesale & retail | 2015 |
| Andrew Close Limited | Administrative & support | 1980 |
| Andrew Mark Aluminium Shopfronts Limited | Construction | 1973 |
| ANK LG Ltd | Construction | 2024 |
| Anna Price Designs Ltd | Manufacturing | 2016 |
| Annos Limited | Professional & scientific | 2022 |
| Anto Limited | Information & communication | 2025 |
| AP Chick Ltd | Manufacturing | 2018 |
| APC Accounting Limited | Professional & scientific | 2019 |
| Apply Wise Financial Ltd | Financial services | 2025 |
| Approach Golf Limited | Arts & recreation | 2002 |
| Approved Care Solutions Ltd | Health & social care | 2024 |
| Aqcuisine.Com Ltd | Hospitality | 2021 |
| Archive Facilities (Southend) Limited | Arts & recreation | 2009 |
| Archizone Site Services Ltd | Construction | 2024 |
| Ardus Group Ltd | Real estate | 2024 |
| ARM Builders Ltd | Construction | 2023 |
| Armis Consultancy Limited | Information & communication | 2010 |
| Arowanaa Services Limited | Wholesale & retail | 2015 |
| Arrow Building and Property Maintenance Limited | Construction | 2017 |
| Arrow Car & Commercial Ltd. | Wholesale & retail | 2012 |
| Arrowsmith & Roberts Limited | Transport & logistics | 2005 |
| Arthur Branwell & Co. Limited | Administrative & support | 1904 |
| ARTHUR39 Ltd | Transport & logistics | 2019 |
| Arthurmay Limited | Professional & scientific | 2018 |
| Artisan Cars Limited | Wholesale & retail | 2018 |
| Artisan Family Ltd | Hospitality | 2021 |
| Arwa Trading Ltd | Wholesale & retail | 2020 |
| Asb-Mcm Holdings Ltd | Real estate | 2020 |
| Asbestos Solutions Ltd | Water & waste | 2014 |
| Ashlyns Farm Limited | Wholesale & retail | 2011 |
| Ashlyns Leisure Limited | Wholesale & retail | 2021 |
| Ashview Contracts Limited | Construction | 2012 |
| Ashview Joinery Limited | Construction | 2015 |
| ASK Property Solutions Limited | Real estate | 2011 |
| Associated Technical Services Ltd | Information & communication | 2014 |
| Aston Maintenance Ltd | Construction | 2023 |
| Aston-An Limited | Financial services | 2020 |
| Astrix Personnel Limited | Education | 2024 |
| ATA Consulting Ltd | Professional & scientific | 2021 |
| Atatio Interactive Ltd | Information & communication | 2024 |
| Atlas Family Group Ltd | Real estate | 2019 |
| Atlas Power & Illumination Company Ltd | Administrative & support | 2025 |
| ATS Automotive Ltd | Wholesale & retail | 2025 |
| Aucspace Limited | Information & communication | 2019 |
| Ault Investments Limited | Real estate | 1957 |
| Aupeer CIC | Health & social care | 2021 |
| Aurora Yoga Ltd | Arts & recreation | 2021 |
| Aurum Forest Limited | Real estate | 2006 |
| Autismvisuals Limited | Education | 2024 |
| Auto Angel Systems Ltd | Information & communication | 2025 |
| AVA Rose Boutique Limited | Wholesale & retail | 2024 |
| AWP Facilities Management Ltd | Administrative & support | 2025 |
| Axiom Fuse Limited | Professional & scientific | 2025 |
| Ayari Investments Ltd | Real estate | 2025 |
| Ayton Project Management Limited | Construction | 2023 |
| B J M Builders Limited | Real estate | 2003 |
| B.E. Essentials Limited | Wholesale & retail | 2013 |
| B.E. Natural Retail Ltd | Wholesale & retail | 2016 |
| B2B Capitals Ltd | Professional & scientific | 2022 |
| Baines Roofing Limited | Construction | 2014 |
| Bakemyday Essex Ltd | Manufacturing | 2025 |
| Bala's Blitzers Limited | Administrative & support | 2020 |
| Bali Rose Consultancy Ltd | Professional & scientific | 2021 |
| Bambidoos Ltd | Wholesale & retail | 2025 |
| Bar:Suds Limited | Manufacturing | 2020 |
| Bard International Limited | Wholesale & retail | 1994 |
| Barnet Dining Ltd | Hospitality | 2025 |
| Barrons Residential Ltd | Real estate | 2013 |
| Bartlett Homes Ltd | Real estate | 2020 |
| Basalt Georgia Ltd | Construction | 2022 |
| Bassett Business Units Limited | Real estate | 1990 |
| Bassett Fork Trucks Limited | Manufacturing | 2007 |
| Bates Taylor Limited | Households | 2024 |
| Bauhaus MFR Ltd | Construction | 2023 |
| BCT Consultancy Ltd | Professional & scientific | 2015 |
| BE Lucky Films Limited | Information & communication | 2025 |
| Be-You-Tea Aesthetics Ltd | Other services | 2025 |
| Beaumont Elite Roofing Ltd | Construction | 2026 |
| Bebekish Bamboo & Organic Ltd | Wholesale & retail | 2020 |
| Beckett Solar Limited | Construction | 2025 |
| Beech and Green Limited | Administrative & support | 2014 |
| Belforest Limited | Real estate | 2003 |
| Belgique (Theydon) Limited | Hospitality | 2011 |
| Belgique of Epping Limited | Hospitality | 2020 |
| Beling & Co Limited | Health & social care | 2005 |