| Avizinis (UK) Scaffolding Limited | Construction | 2013 |
| AVJ Group Ltd | Construction | 2017 |
| AVL Powertrain UK Limited | Professional & scientific | 2005 |
| AVM Automotive Ltd | Wholesale & retail | 2023 |
| AVN Granite Ltd | Construction | 2020 |
| Avondale ETS Ltd | Construction | 2017 |
| Avonmill Services Limited | Construction | 2015 |
| Avprotech Limited | Other services | 2022 |
| Avwa Limited | Real estate | 2024 |
| AW London Contractors Ltd | Construction | 2023 |
| AWC PPF Limited | Wholesale & retail | 2018 |
| Awrb Consultancy Limited | Professional & scientific | 2024 |
| Axerian Ltd | Wholesale & retail | 2020 |
| Axis Geomatics Ltd | Professional & scientific | 2026 |
| Axis Medical Services South East Limited | Health & social care | 2012 |
| Axis Precision Engineering Components Limited | Manufacturing | 1985 |
| Axspr Limited | Wholesale & retail | 2018 |
| AYA Express Ltd | Transport & logistics | 2024 |
| Ayaan Imran Ltd | Wholesale & retail | 2026 |
| AYC Construction Limited | Construction | 2014 |
| Ayers & Cruiks Trustees Limited | Professional & scientific | 2025 |
| Ayoka Ltd | Health & social care | 2023 |
| Ayonbay Services Ltd | Administrative & support | 2021 |
| Ayoyem Company Limited | Professional & scientific | 2005 |
| Ayvon Carter Transport Ltd | Transport & logistics | 2022 |
| Azguard Holdings Limited | Financial services | 2022 |
| Azrah Consultancy Ltd | Professional & scientific | 2024 |
| Aztech Vehicle Security Limited | Wholesale & retail | 2021 |
| Azur Services (South East) Limited | Hospitality | 2014 |
| Azure Living Ltd | Real estate | 2025 |
| AZZ Private Ltd | Transport & logistics | 2025 |
| Azza Medical Services Ltd | Wholesale & retail | 2026 |
| B & E Parkin Leisure Limited | Arts & recreation | 1998 |
| B DOT Enterprise Limited | Professional & scientific | 2016 |
| B Drake Decorating Ltd | Construction | 2021 |
| B F Operations Limited | Other services | 2015 |
| B H Dental Laboratory Limited | Health & social care | 2002 |
| B I Technology Essex Limited | Manufacturing | 2010 |
| B Jordan Ltd. | Information & communication | 2013 |
| B M G 1995 Ltd | Other services | 2020 |
| B Seen Online Ltd | Administrative & support | 2018 |
| B&B Consultants Ltd | Administrative & support | 2018 |
| B&H Land and Commercial Ltd | Real estate | 2025 |
| B&J Building Ltd | Construction | 2019 |
| B&O Guttering Limited | Administrative & support | 2023 |
| B&S Fresh Spaces Ltd | Administrative & support | 2025 |
| B&S Investments (Essex) Limited | Real estate | 2021 |
| B. Richardson Services Limited | Construction | 2009 |
| B. Ross Welding Limited | Manufacturing | 2016 |
| B.Aria Consults Limited | Financial services | 2017 |
| B.B. Transport Limited | Transport & logistics | 1997 |
| B.F. Humphrys Limited | Construction | 1999 |
| B2B ETM UK Limited | Administrative & support | 2024 |
| B2B Marketing Specialists Ltd | Administrative & support | 2019 |
| B2B Pro Construct Ltd | Construction | 2023 |
| B4 Industrial Products Limited | Wholesale & retail | 1999 |
| BA Griffin Limited | Construction | 2023 |
| BAB Essex Group Limited | Construction | 2022 |
| Baba Ajagbe Limited | Public administration | 2024 |
| Babble Cloud (MD) Limited | Information & communication | 2022 |
| Babble Cloud Holdings Limited | Information & communication | 2017 |
| Babble Cloud Limited | Information & communication | 2001 |
| Bablo Consultancy Limited | Information & communication | 2014 |
| Baby Bunch Limited | Wholesale & retail | 2010 |
| Baby D Limited | Wholesale & retail | 2021 |
| Baciley Scaffolding Limited | Construction | 2014 |
| Backside to Trackside CIC | Health & social care | 2023 |
| Baco Consulting Limited | Information & communication | 2013 |
| Baddow Mini Market Limited | Hospitality | 2025 |
| Badysveol Ltd | Construction | 2025 |
| BAE Training Academy Limited | Other services | 2025 |
| Bafisa Luxe Limited | Real estate | 2025 |
| Baglogix Limited | Manufacturing | 2007 |
| Bagshawe Consulting Limited | Professional & scientific | 2024 |
| Bailar Benfleet Limited | Other services | 2013 |
| Bailar Billericay Limited | Other services | 2013 |
| Bailar Events Limited | Other services | 2022 |
| Bainazs Ltd | Health & social care | 2018 |
| Baker Estates Essex Limited | Real estate | 2019 |
| Bali Vintage Brand Ltd | Wholesale & retail | 2024 |
| Balin Distribution Limited | Transport & logistics | 1975 |
| Balloon Decor Ltd | Wholesale & retail | 2000 |
| Balmoral Itechnology Consulting Limited | Information & communication | 2025 |
| Balog Cleaning Contractors Ltd | Administrative & support | 2016 |
| Baltic Service Solutions Ltd | Construction | 2019 |
| BAM Carpentry Ltd | Construction | 2019 |
| Bamboo Funding Limited | Financial services | 2018 |
| Bamg Sports Ltd | Information & communication | 2020 |
| Bamicare Limited | Health & social care | 2018 |
| Bamo Investment Ltd | Real estate | 2024 |
| Bananas Body Art Ltd | Other services | 2005 |
| Bandptcgstore Ltd | Wholesale & retail | 2026 |
| Banham Estates Limited | Real estate | 2008 |
| Bannerbridge Holdings Limited | Professional & scientific | 2012 |
| Bannerbridge Limited | Information & communication | 1981 |
| Bannerbridge Management Services LLP | | 2011 |
| BAP Interiors Ltd | Construction | 2018 |
| Bar-N-Bus Trust | Other services | 1994 |
| Barber Brickwork Limited | Construction | 2021 |
| Barber Financial Solutions Limited | Professional & scientific | 2013 |