| Businesslpa Limited | Professional & scientific | 2016 |
| Buzi Management Services Limited | Professional & scientific | 2023 |
| Buzzbees Pest Control Ltd | Professional & scientific | 2023 |
| Byam Limited | Wholesale & retail | 2020 |
| Byethief Limited | Administrative & support | 2023 |
| Byrne Surveys Ltd | Construction | 2018 |
| Byspiritualdaz Limited | Wholesale & retail | 2025 |
| Byteal Ltd | Information & communication | 2015 |
| Bzzbee Ltd | Wholesale & retail | 2022 |
| Bzzbeeuk Limited | Wholesale & retail | 2026 |
| C & C Acquisitions Ltd | Real estate | 2020 |
| C & C Property & Management Services Ltd | Construction | 2021 |
| C & C Services (Essex) Limited | Construction | 2018 |
| C & L Contractors Limited | Construction | 2020 |
| C & M Trade Supplies Ltd | Wholesale & retail | 2018 |
| C and B Capital Ltd | Real estate | 2016 |
| C B K Property Investments Limited | Other services | 2010 |
| C E Strategy Ltd | Professional & scientific | 2024 |
| C George Estates Limited | Real estate | 2024 |
| C J Construction South East Limited | Construction | 2021 |
| C Johnson and SON Ltd | Wholesale & retail | 2009 |
| C&C Willats Ltd | Hospitality | 2025 |
| C&D Accounts Limited | Professional & scientific | 2019 |
| C&G Maintenance Ltd | Construction | 2023 |
| C&J Environmental Services Ltd | Water & waste | 2025 |
| C&L Ductwork Ltd | Professional & scientific | 2026 |
| C. & S. Instrument Services Limited | Manufacturing | 1973 |
| C.I. Silochi Ltd | Extraterritorial | 2020 |
| C.P. Holdings (UK) Limited | Professional & scientific | 1998 |
| C.P. Property Investments Limited | Real estate | 2001 |
| C.Taylors Coaches Ltd | Transport & logistics | 2021 |
| C002 Services Ltd | Administrative & support | 2025 |
| C7 Joshi Ltd | Health & social care | 2025 |
| Caber Digital Limited | Information & communication | 2021 |
| Cabin Interiors Ltd | Manufacturing | 2019 |
| Cachia Family Properties Limited | Financial services | 2020 |
| Cachia Holding Company Limited | Real estate | 1973 |
| Cafe MAX (Benfleet) Limited | Hospitality | 2016 |
| Caka Limited | Hospitality | 2015 |
| Calibre Publishing Limited | Information & communication | 2012 |
| Call Centre Facilities LLP | | 2017 |
| Callow Sinclair Design Limited | Administrative & support | 2003 |
| Calmrule Limited | Real estate | 1984 |
| CAM Developments Limited | Construction | 1998 |
| Cama Property Solutions Limited | Real estate | 2025 |
| Cambria Investments Limited | Administrative & support | 1998 |
| Cambridge Access Solutions Ltd | Construction | 2025 |
| Camelot Day Nursery Limited | Education | 2011 |
| Camo Airsoft Arena Ltd | Arts & recreation | 2024 |
| Camo Airsoft Store Ltd | Wholesale & retail | 2024 |
| Camoraids Ltd | Wholesale & retail | 2023 |
| Candlelight Court Romford Road Stratford Management Limited | Households | 2003 |
| Canetic Services Ltd | Health & social care | 2024 |
| Cannon Property Renovations Limited | Construction | 2016 |
| Canvey Building Supplies Limited | Extraterritorial | 2014 |
| Canvey Castles Limited | Arts & recreation | 2022 |
| Canvey Island Autos & Accessories Limited | Wholesale & retail | 2002 |
| Canvey TAN Ltd | Other services | 2024 |
| CAP Site Services Ltd | Professional & scientific | 2017 |
| Capital City Asset Management Limited | Real estate | 2006 |
| Capital Resins Ltd | Construction | 2024 |
| Capon & Capon Limited | Wholesale & retail | 1964 |
| Capps Van Sales UK Limited | Wholesale & retail | 2024 |
| Car Hideaway Ltd | Transport & logistics | 2025 |
| Car Key MAN Ltd | Wholesale & retail | 2025 |
| Care SPV Ltd | Financial services | 2025 |
| Carers Choices | Health & social care | 2001 |
| Carman Bathworld Ltd | Construction | 2021 |
| Carman Heating Supplies Limited | Construction | 2006 |
| Carnaby Production and Management Services Limited | Information & communication | 2006 |
| Caroline Jones Mortgage Services Ltd | Financial services | 2018 |
| Carpentry & Construction Essex Limited | Construction | 2022 |
| Carshop Essex Limited | Wholesale & retail | 2024 |
| Carvosso Curtains & Blinds Ltd | Wholesale & retail | 2014 |
| Casiold Limited | Wholesale & retail | 2025 |
| Castle Point Accountancy Ltd | Professional & scientific | 2010 |
| Castle Point Association of Voluntary Services Limited | Administrative & support | 2003 |
| Castle Point Building Supplies Ltd | Extraterritorial | 2017 |
| Castle Point GAS & Heating Co. Limited | Other services | 1983 |
| Castle Point Plastics Limited | Construction | 2013 |
| Castle Point Reclaim Ltd | Extraterritorial | 2017 |
| Castle Point Security Solutions Ltd | Construction | 2026 |
| Castle Point Skips Limited | Extraterritorial | 2012 |
| Castle Point Social Car Scheme Limited | Transport & logistics | 1999 |
| Castle Point Timber Supplies Ltd | Extraterritorial | 2017 |
| Catherine Watkins Ltd | Financial services | 2026 |
| Cathmart Advisors Limited | Real estate | 2015 |
| Caulfield Property Services Ltd | Construction | 2022 |
| Cavalier Services Ltd | Administrative & support | 2020 |
| CAW Air Conditioning Ltd | Construction | 2026 |
| CB Developments (Essex) Limited | Real estate | 2017 |
| CBK Community Boxing Ltd | Arts & recreation | 2026 |
| CC Education & Training Ltd | Education | 2026 |
| Cc's Cafe Ltd | Wholesale & retail | 2019 |
| CDL Scaffolding Supplies Ltd | Construction | 2020 |
| Cdon Investment Ltd | Real estate | 2025 |
| Cedes Music Ltd | Information & communication | 2020 |
| Certified by JAY Ltd | Administrative & support | 2026 |
| CG Rail Solutions Limited | Administrative & support | 2007 |
| Cgreavesbuildingandlandscapes Limited | Construction | 2026 |