| C D Landscapes (Essex) Limited | Administrative & support | 2015 |
| C Hoult IT Solutions Ltd | Information & communication | 2011 |
| C J Ashby Limited | Agriculture & fishing | 2023 |
| C Jones Property Ltd | Real estate | 2023 |
| C M Accountancy Ltd | Professional & scientific | 2002 |
| C M Cost Consultancy Limited | Professional & scientific | 2008 |
| C N KOI Ltd | Agriculture & fishing | 2026 |
| C P Whybrow Ltd | Wholesale & retail | 2010 |
| C Thorpe Plastering Contractor Ltd | Construction | 2025 |
| C.A.R.S. UK Holdings Limited | Financial services | 2015 |
| C.J.Ashby Forestry Limited | Agriculture & fishing | 2011 |
| C.J.Ashby Timber Haulage Limited | Agriculture & fishing | 2017 |
| Cabizz Ltd | Transport & logistics | 2022 |
| CAD Consortium Ltd | Construction | 2026 |
| CAD Windows Ltd | Construction | 2026 |
| Cafe in the Park & Leisure Colchester Limited | Hospitality | 2018 |
| Cahillbrand Ltd | Information & communication | 2016 |
| Cake Boxes Direct Limited | Wholesale & retail | 2009 |
| Calibr Holdings Ltd | Wholesale & retail | 2022 |
| Callala Ltd | Professional & scientific | 2021 |
| Callamae Limited | Real estate | 2020 |
| CAM Assets Limited | Real estate | 2019 |
| CAM Holdingco Limited | Financial services | 2026 |
| CAM Investco Limited | Construction | 2026 |
| Camelot Productions Limited | Wholesale & retail | 2002 |
| Campbell Path Ltd | Public administration | 2022 |
| Cannon Motorsport Ltd | Wholesale & retail | 2017 |
| Canonbury Lane Management Limited | Households | 1989 |
| Canonsleigh Ventures Limited | Professional & scientific | 1991 |
| Canute Investments Limited | Administrative & support | 2001 |
| Caon Limited | Real estate | 2022 |
| Capital Land Developments Ltd | Real estate | 2020 |
| Caprice Atelier Ltd | Manufacturing | 2023 |
| Caramarine (SW) Limited | Wholesale & retail | 2015 |
| Card Universe Ltd | Wholesale & retail | 2021 |
| Care Expert Services Ltd | Health & social care | 2023 |
| Care With Purpose Group Ltd | Professional & scientific | 2026 |
| Carlton House Asset Management Limited | Real estate | 2002 |
| Carnage Cards TCG Ltd | Wholesale & retail | 2025 |
| Carneiro-Hart Properties Ltd | Real estate | 2024 |
| Carritrans (UK) Limited | Transport & logistics | 2003 |
| Carrowe Logistics Limited | Transport & logistics | 2024 |
| Cascai Projects Limited | Construction | 2026 |
| Cashmere Moon Ltd | Extraterritorial | 2022 |
| Catalyst Group Limited | Wholesale & retail | 2019 |
| Catchburn Farm Limited | Professional & scientific | 2021 |
| Catchburn Limited | Professional & scientific | 2021 |
| Caterelle Limited | Other services | 1979 |
| Caulkett Professional Construction Services Ltd | Professional & scientific | 2022 |
| CC Insulation Ltd | Construction | 2025 |
| Ccal Group Ltd | Information & communication | 2026 |
| CCC Pathology Limited | Health & social care | 2024 |
| CCS Air Conditioning Limited | Construction | 2005 |
| CDE Associates Limited | Construction | 2016 |
| Cdmp Holdings Limited | Construction | 2014 |
| CE Tax Limited | Professional & scientific | 2017 |
| Cedar Land Management Limited | Professional & scientific | 2008 |
| Ceebsworld Ltd | Wholesale & retail | 2024 |
| Cemetery Ground Services Limited | Other services | 2024 |
| Central Business Park Management (Kent) Limited | Real estate | 1988 |
| Central Line Engineering Limited | Manufacturing | 2007 |
| Centurion Cleaning Limited | Construction | 2015 |
| Ceramic Services Limited | Construction | 1993 |
| CES Financial Limited | Financial services | 2021 |
| CES Maldon Limited | Construction | 2017 |
| CGH Investments Ltd | Information & communication | 2020 |
| Cghealey Consulting Ltd | Administrative & support | 2017 |
| Chadron Investments Limited | Administrative & support | 1988 |
| Chadwick Square Freehold Limited | Households | 2017 |
| Chadwick Square Management Limited | Households | 2000 |
| Chalkwell Hall Estates Limited | Real estate | 2016 |
| Challenger Designs Limited | Professional & scientific | 2016 |
| Chambers Financial Services Limited | Financial services | 2012 |
| Champion Motors Limited | Wholesale & retail | 2004 |
| Chandlers Freehold Limited | Real estate | 2016 |
| Changing Elements CIC | Arts & recreation | 2024 |
| Chapman Place Management Company Limited | Households | 2000 |
| Chard Garden Centre Limited | Wholesale & retail | 2019 |
| Charterhouse Safety Ltd | Professional & scientific | 2026 |
| Chartwell Suffolk Ltd. | Wholesale & retail | 2010 |
| Chathaus Ltd | Information & communication | 2025 |
| Chauffeur ME Travel Ltd | Transport & logistics | 2026 |
| CHB Rigging Ltd | Information & communication | 2024 |
| Chelmech Services Limited | Construction | 2024 |
| Chelmer Heritage Limited | Construction | 2005 |
| Chelmer Media Ltd | Professional & scientific | 2025 |
| Chelmer Medical Services Ltd | Health & social care | 2014 |
| Chelmsford City Motorcycles Ltd | Wholesale & retail | 2014 |
| Chelmsford Digger Hire Ltd | Administrative & support | 2017 |
| Chelmsford Garden Machinery Ltd | Administrative & support | 2022 |
| Chelmsford Glass Limited | Extraterritorial | 2009 |
| Chelsea Interiors Ltd | Construction | 2024 |
| Chenglihang Trusted Trading Limited | Administrative & support | 2022 |
| Cherry Grove Investments Limited | Real estate | 2014 |
| Chichester Tools Ltd | Wholesale & retail | 2015 |
| Chigborough Carp Syndicate Limited | Agriculture & fishing | 2012 |
| Chigborough Events Limited | Arts & recreation | 2025 |
| Chigborough Farms Ltd | Hospitality | 2014 |
| Chois Marketing and Trading Ltd | Wholesale & retail | 2022 |
| Chris's Fish Bar Ltd | Hospitality | 2022 |