| Atlantic TS Limited | Administrative & support | 2006 |
| Audley Chase (Earls Colne) Management Company Limited | Households | 2020 |
| Aura Reforma Ltd | Arts & recreation | 2025 |
| Aurora Group Services Limited | Administrative & support | 2021 |
| Autism Respite and Advocacy Limited | Health & social care | 2023 |
| AVA Jewels (U.K.) Limited | Wholesale & retail | 2005 |
| Avenue Convenience Store Ltd | Wholesale & retail | 2023 |
| Avenues of Frinton Limited | Wholesale & retail | 1999 |
| Avni Car Sales Ltd | Wholesale & retail | 2023 |
| Avondale Developments (Essex) Ltd | Construction | 2023 |
| Avsr Services Limited | Information & communication | 2025 |
| AXS Energy Consulting Limited | Information & communication | 2017 |
| B E Fosker Electrical Contractors Ltd | Manufacturing | 2008 |
| B Networks Ltd | Information & communication | 2020 |
| B.F.J.L. Ltd | Wholesale & retail | 2018 |
| B.Turner Properties Limited | Real estate | 2021 |
| Baby Squids Colchester Ltd | Education | 2023 |
| Badr Transport Ltd | Transport & logistics | 2026 |
| BAK Design & Construction Ltd | Wholesale & retail | 2022 |
| Balance and Build Support Ltd | Education | 2025 |
| Ballagh Care Ltd | Administrative & support | 2012 |
| Baloso Ltd | Health & social care | 2014 |
| Balti House Indian Cuisine Limited | Hospitality | 2016 |
| Barnard Developments Ltd | Real estate | 2019 |
| Barnes & Torr Ltd | Administrative & support | 2017 |
| Barney & Paws Ltd | Wholesale & retail | 2025 |
| Bashky Limited | Real estate | 2022 |
| Baxter Laois Limited | Wholesale & retail | 2015 |
| Baylys Baits Limited | Agriculture & fishing | 2020 |
| BAZ CUT Ltd | Other services | 2023 |
| BD Choice Ltd | Wholesale & retail | 2025 |
| BDF Group Ltd | Professional & scientific | 2023 |
| BDK Cleaning Ltd | Administrative & support | 2023 |
| BE a Better Biker Ltd | Education | 2010 |
| BE Trained Essex Ltd | Education | 2023 |
| Beardies Associates Limited | Administrative & support | 2010 |
| Beaumont Bespoke Limited | Construction | 2025 |
| BEAUTYZONE2 Ltd | Other services | 2025 |
| Becca Play Therapy Services Limited | Health & social care | 2021 |
| BED Centres 146 Ltd | Wholesale & retail | 2021 |
| Bedzz & Bits Limited | Wholesale & retail | 2020 |
| BEE Cleans & BEE Your Plan Ltd | Administrative & support | 2025 |
| BEE Smart Mortgages Limited | Financial services | 2023 |
| Bee-Line Entertainment Ltd | Transport & logistics | 2014 |
| Bee-Line Logistical Solutions Ltd | Transport & logistics | 2009 |
| Beechouse Ltd | Real estate | 2020 |
| Beetrue People Services Limited | Professional & scientific | 2024 |
| Beeyond Pest Control Ltd | Administrative & support | 2020 |
| Belmont Motors Ltd. | Wholesale & retail | 2002 |
| BEN Poole's Rail Limited | Construction | 2018 |
| Bennett Asset Group Ltd | Wholesale & retail | 2026 |
| Bentley Fencing Supplies Ltd | Administrative & support | 2011 |
| Bentley Landscapes Ltd | Administrative & support | 2021 |
| Bentley Mill Developments Limited | Construction | 2020 |
| Bersim Care Ltd | Real estate | 2023 |
| Bersim Care Properties Ltd | Real estate | 2024 |
| Bespoke Property Management Services Limited | Real estate | 2015 |
| Best HR Solutions Limited | Administrative & support | 2026 |
| Best Mart(Pink Shop) Ltd | Wholesale & retail | 2024 |
| Betts Property Services Ltd | Real estate | 2022 |
| BF & ET Lumber Ltd | Extraterritorial | 2021 |
| BG Grill Ltd | Hospitality | 2025 |
| Bhavin Express Ltd | Wholesale & retail | 2022 |
| Bhavin Limited | Wholesale & retail | 2024 |
| Big Red Utilities Limited | Energy | 2026 |
| Bilbas Store Ltd | Wholesale & retail | 2026 |
| Bill Rees and Company Limited | Wholesale & retail | 1987 |
| Billy’S Burger Bar Ltd | Hospitality | 2024 |
| Binks Bespoke Carpentry & Building Limited | Construction | 2025 |
| Birdsong Accountancy Ltd | Professional & scientific | 2023 |
| BJB Properties Limited | Real estate | 2025 |
| BKD Performers Ltd | Arts & recreation | 2017 |
| BKG Electrical Ltd | Construction | 2025 |
| Black Hotels Ltd | Hospitality | 2021 |
| Black Sabbath Limited | Professional & scientific | 2002 |
| Blackened Sun Productions Ltd | Manufacturing | 2023 |
| Blacklystudios Ltd | Arts & recreation | 2026 |
| Blackout Media Ltd | Professional & scientific | 2025 |
| Blackrock Steakhouse Ltd | Hospitality | 2023 |
| Blakes Woodburners Ltd | Construction | 2021 |
| Blandford Consultancy Limited | Other services | 2011 |
| Blessed Builder Ltd | Construction | 2025 |
| Blkuzz Ltd | Information & communication | 2025 |
| Bloomsbury Home Care Limited | Health & social care | 2008 |
| Bloomsbury KG Limited | Health & social care | 2008 |
| Blossom Healthcare North Ltd | Health & social care | 2025 |
| Blue House Manor Developments Ltd | Households | 2018 |
| Blue Skyz Ltd | Wholesale & retail | 2025 |
| Blueprint Contractors Limited | Construction | 2016 |
| Blueridge Services Ltd | Professional & scientific | 2025 |
| Bluerock Resources Ltd | Administrative & support | 2024 |
| Blush Films Limited | Information & communication | 2023 |
| BM Original Ltd | Hospitality | 2021 |
| BM Rail Solutions Ltd | Manufacturing | 2026 |
| BMY IT Services Ltd | Information & communication | 2024 |
| Bodyclock Fitness Limited | Arts & recreation | 2018 |
| Bondotrans Ltd | Transport & logistics | 2025 |
| Bookfully Ltd | Information & communication | 2026 |
| Booth's Education Services and Tutoring Ltd | Education | 2022 |
| Bootleggers Convenience Store Limited | Wholesale & retail | 2020 |