| Barlwuk Ltd | Information & communication | 2019 |
| Barrington Real Estate Limited | Real estate | 2012 |
| Barringtons Property Consultants Ltd | Real estate | 2012 |
| Barton-Wells Limited | Information & communication | 2014 |
| BAT Projects Limited | Construction | 2026 |
| Bear & Co Equine LLP | | 2021 |
| Bear Builds Limited | Construction | 2018 |
| Beaumont Global Healthcare Ltd | Administrative & support | 2025 |
| Belles Weddings and Events Ltd | Administrative & support | 2026 |
| Bellhouse Aesthetics Ltd | Health & social care | 2023 |
| Bellstar Properties Limited | Construction | 1993 |
| Belsquare Limited | Construction | 2026 |
| BEN Russell Holdings Ltd | Financial services | 2023 |
| Bennetts Farm Shooting Ground Limited | Arts & recreation | 2025 |
| Best Pizza and Chicken Ltd | Hospitality | 2025 |
| Betty Snowboarding Limited | Arts & recreation | 2024 |
| Big Swim Little Swim Limited | Education | 2023 |
| Bigwood`S Tachograph Services Limited | Manufacturing | 2008 |
| Biodiversity and Carbon Network Ltd | Agriculture & fishing | 2023 |
| Birdies Beauty Ltd | Other services | 2021 |
| Black Manta Group Ltd | Professional & scientific | 2021 |
| Blackmore Four Limited | Professional & scientific | 2017 |
| Blackmore Swim School Limited | Education | 2024 |
| Blackmore Workshops Ltd | Wholesale & retail | 2010 |
| Blacksquare Solutions Limited | Administrative & support | 2013 |
| Blagper Holdings Limited | Financial services | 2026 |
| Blake Swimwear Limited | Wholesale & retail | 2024 |
| Blakes Leisure Limited | Arts & recreation | 2012 |
| Bloomfield Trading Ltd | Financial services | 2019 |
| Blue Train Consulting Ltd | Professional & scientific | 2025 |
| Bluebells Brickwork Ltd | Construction | 2024 |
| Bookkeeping Essex Limited | Professional & scientific | 2009 |
| Boswell Builders Ltd | Construction | 2011 |
| Brandler Galleries (Brentwood) Limited | Arts & recreation | 1959 |
| Braysum Property Ltd | Real estate | 2018 |
| Breckland Mobile Mechanic Limited | Wholesale & retail | 2026 |
| Brentwood Half Marathon C.I.C. | Health & social care | 2026 |
| Brentwood Hard Court Tennis Club Ltd | Arts & recreation | 2025 |
| Brian Allen PHC Ltd | Construction | 2013 |
| Bridge Office Interiors Limited | Wholesale & retail | 2007 |
| Brittania Properties Limited | Construction | 1992 |
| Brookmans Farm Dairy Limited | Agriculture & fishing | 1963 |
| Brownbread Bakery Limited | Manufacturing | 2019 |
| Bryanton Property Investments Ltd | Hospitality | 2026 |
| BTL Galaxy Homes Ltd | Real estate | 2025 |
| Building Success Ltd | Real estate | 2015 |
| Buildlaw Ltd. | Professional & scientific | 2025 |
| Business Management Specialists Ltd | Other services | 2017 |
| Butterfly Care Group Ltd | Health & social care | 2024 |
| Butterfly Hold Co Ltd | Health & social care | 2025 |
| Butterfly House Dementia Care Ltd | Health & social care | 2024 |
| Butterfly House OP Co Ltd | Health & social care | 2025 |
| Butterfly House Prop Co Ltd | Health & social care | 2025 |
| C & G Utilities Ltd | Construction | 2023 |
| C & G Works Division Limited | Construction | 2012 |
| C R Dulake Consulting Limited | Professional & scientific | 2025 |
| C R Swift Landscapes Ltd | Administrative & support | 2022 |
| C S Tubes Limited | Wholesale & retail | 2023 |
| C&C Quality Meats Limited | Wholesale & retail | 2026 |
| C&F Construction Services Limited | Construction | 2025 |
| C.A.P. Carpentry and Joinery Ltd | Manufacturing | 2017 |
| C.G.P.L Ltd | Construction | 2018 |
| Cadena Limited | Real estate | 2022 |
| Cadena Property Co Ltd | Real estate | 2023 |
| Cadl Consultancy Ltd | Professional & scientific | 2022 |
| Cam-Ri Limited | Administrative & support | 1981 |
| Camway Facilities Maintenance Limited | Other services | 1997 |
| Camway Resources Limited | Other services | 2011 |
| Candover Consultants Limited | Professional & scientific | 2010 |
| Cannon Street (Preston) Management Co Limited | Households | 2026 |
| Canonbury Roofing Ltd | Construction | 2011 |
| Canthy Ltd | Real estate | 2019 |
| Capital Holdings (Standford-Le-Hope) Ltd | Construction | 2019 |
| Capital Holdings Group Ltd | Real estate | 2019 |
| Care Consortium Limited | Financial services | 2025 |
| Care Support Services Limited | Health & social care | 2025 |
| Caring Solutions LLP | | 2024 |
| Carter 2000 Ltd | Information & communication | 2023 |
| Cashman Access Ltd | Construction | 2021 |
| Caviepiu Limited | Wholesale & retail | 2025 |
| CB & BB Services Ltd | Construction | 2022 |
| CEB Group (Holdings) Ltd | Financial services | 2019 |
| CEB Property Ltd | Real estate | 2018 |
| Cement and Concrete Research Centre Ltd | Professional & scientific | 2024 |
| Center Stage Ltd | Professional & scientific | 2025 |
| Cerevet Limited | Professional & scientific | 2014 |
| Chain Bridge Meadow Residents Limited | Households | 2019 |
| Chalmers Agency Limited | Real estate | 2022 |
| Chalmers Limited | Real estate | 2022 |
| Chase Farm Ltd | Real estate | 2014 |
| CHB Residents Association Limited | Households | 2011 |
| Chelmer Consultants Limited | Professional & scientific | 2009 |
| Chestergate Estates Limited | Construction | 1991 |
| Cirencester Physiotherapy Centre Ltd | Other services | 2020 |
| Cjsm Holdings Limited | Real estate | 2025 |
| Claire Gallagher Ltd | Professional & scientific | 2022 |
| Classic Roofing and Building Services Ltd | Construction | 2021 |
| Clifford Developments Limited | Real estate | 2024 |
| Cloudline Media Ltd | Professional & scientific | 2024 |
| Cloudscaler Limited | Information & communication | 2018 |